# My own Amplifier Sound Quality Shootout



## JCsAudio (Jun 16, 2014)

This has been posted many times and debated to death here. Is there a sound quality difference between amplifiers given that they are of good quality and at a reasonable price point? I was of the camp that believed that in a blind test no one could tell a difference so long as gains where set exactly equal and power range was within the amplifiers specified range (no clipping or under clipping). 

So the Amplifier shootout by Matt Hall posted here gave me the idea to try and test this theory for myself as best I could in my garage with a blind listening test using my ears and my wife’s ears to be the judge, and by my modest means. My wife who is very much into music can recall any lyric to any song you can think of without stopping to think about it. She has become accustomed to good sounding systems thanks to me. I would consider her ears the best trained I have and also her hearing is better than mine. I’ve outfitting all of her vehicles over the years with some pretty nice sounding systems, including the full active system in her Toyota Sienna now. 

The Test equipment consisted of some Kef C45 bookshelf speakers and a Parts Express Mean Well power supply to power the amplifiers at 14 volts. The benchmark amplifier I used to compare all my others in this test to is an Alpine 3548 2 channel 60 wpc Class AB amplifier made in Japan from the early 90’s, when Alpine made some top shelf awesome sounding stuff. I describe this amplifiers sound as dynamic, open, airy, and natural sounding, plus it’s the best one I have. Playing music through this amplifier makes the music come alive. I picked this amplifier up new back in the early nineties and it was one of the first amplifiers I owned.

The test consisted of swapping the speaker leads at the speakers to the amplifiers with quick connect banana plugs so I could swap amplifiers in less than 30 seconds. I did this by hooking up both amplifier’s to the power supply and using a banana plug for the remote turn on wire to only power one amplifier at a time so I didn’t overwhelm the power supply. So I just had to swap the speaker banana plugs to the speakers, remote turn on banana plug to power up one amp at a time, and swap the input RCA to the amplifier for the input source. I used my IPod gen 7, and played some lossless files consisting of Imagine Dragons songs with a phono to RCA adapter to feed directly into the amplifier. I used my Unik microphone and REW to set the gains on the amplifiers by matching their db output exactly to within 1/10 of each other so having one play louder than the other wouldn’t skew the result’s. 

First test was against my Alpine MRP F240, which is a 4 channel 40 wpc amplifier. It served me well and I regarded it as a good sounding amplifier. This amplifier was recently swapped out for my Pioneer D8604 in my truck. The Alpine MRP F240 is a Chinese made Alpine and of class AB design. Let’s just say this one was the easiest to tell the difference. I was actually surprised that I could tell a difference at first. The 3548 by comparison sounded more open, had a wider stage, and more realistic sounding bass. Thinking it was because the MRP F240 has less power, I then bridged it for 100 wpc, and performed the test again and it didn’t seem to make a difference. Remember I set the gain to match the output of the 3548 so only dynamics should change.

Second test was against an NVX MVPA4, which is a Chinese made micro class D amplifier that many people buy for motorcycles or for tight spaces. This amplifier originally served as the main amp for the front stage in my wife’s Sienna because I had to hide it under the dash, and space was extremely tight. It is rated at 50 wpc, although Sonic Electronix's likes to claim it makes way more power, but I do not believe it makes much more power than 50 wpc, and this is based on my experience with it compared to more powerful amplifiers. There was a noticeable difference in sound quality when I swapped this amplifier for a Pioneer D9500F in my wife’s Toyota Sienna, and I’m not sure why I noticed that then but not now. Initially I did the test on this one first and had a harder time telling a difference. I had to run a few more tests for myself, and eventually I noticed that the songs seemed a little more hard edged in the upper frequencies and that the detail from the Alpine seemed to be a little better in the upper high end frequencies. I ran a couple of blind listening tests with my wife and she easily picked out the Alpine 3548 as the better sounding amplifier. Now I owe Sonic and NVX an apology because I kind of bashed this amplifier as sounding much worse than it actually does. It sounds better than the Alpine MRP F240 (class AB) and so did better in this test than I thought it would. 

Third test was against my best class D I have, which is a pioneer PRSD4200 with ICE power design, for whatever that means. Holding this amplifier in my hands shows it’s made to a higher standard. The pots look and feel nice and the switches look and feel like they are of higher quality than typical for this class. When the amplifier turns on, it has a separate relay inside it that makes an audible click. This amplifier is kind of large and heavy too for a 75 wpc class D amplifier. Its specifications are some of the best I’ve seen for the price point and class D design. This amplifier was the one I swapped with that Alpine 3548 in my CX5 over three years ago, and I do not remember noticing a difference in SQ after the swap. The Pioneer is a 4 channel design rated for 75 wpc into 4 ohms and 150 wpc into 2 ohms, so this tells me it has a robust power supply. I did the first listening test and really could not tell a difference, but I also knew which one was playing so my thoughts were biased and I wanted it to win. When my wife did the test (not knowing which one was playing), she asked me to swap them back and forth one more time, but in the end she once again chose the Alpine 3548, stating that this test was the hardest for her to decipher. She said the crispness of the vocals was slightly better when listening to the Alpine 3548, but that this was the hardest for her to tell a difference. For me it’s not enough of a difference that I want to change my amplifiers for something better, but it’s an eye opening test that proves to me that there are small audible differences in sound between different amplifiers. 

Lastly I ran a few pink noise tests and sweeps using my microphone and REW to see if I could measure any differences between all amplifiers. The pink noise testing revealed no real differences nor did the sweeps except for maybe the NVX in a small area. I then just played Imagine Dragons Believer (lossless ripped from a CD) and measured the song in Rew up to 100 averages. This revealed some slight differences of 1 db or less in the upper ranges and I also graphically it looked like there were softer edges to the peaks and valleys in the graph for the Alpine 3548 vs the others. I need to re-measure these though just to make sure that what I’m looking at is accurate.


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## Holmz (Jul 12, 2017)

Where and why they are different would be a different test to answer the same general question of are "they different".


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## 04quadcab (Dec 31, 2017)

Thanks for doing the test and thank you for sharing the results.



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## preston (Dec 10, 2007)

Yeah thanks for posting. Interesting to read. 
I've often wondered if I'm giving up something running the Pioneer DRSP800 mini-amps. They also feel very high quality and are probably fairly well related to the newer 4 channel amp you tested. I'm installing a new system now and planning to use an older RF 4 channel A/B amplifier for the front stage, and I'll have to do compare to using 3 of the mini pioneer amps (1 for midrange/high, and 1 each bridged for the woofers).


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## JCsAudio (Jun 16, 2014)

I’m tempted to pull out my Pioneer D8604 from my truck and do the same test. I’d pull the D9500F from the van too, but that one requires taking apart the Toyota dash to get to it so it’s kind of too much work and the wife won’t like it either. 

If anyone in the area has a 2 or 4 channel amplifier they’ed like to try in this listening test, than just let me know and maybe we can set up a test. I would love to test something higher end to judge just how much of a difference there may or may not be.


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## Holmz (Jul 12, 2017)

I am not sure it is worth te bother.

I put a special set of test tones used for distortion into the tubes amps and out the nice speakers.
Then I took the Mrs old transistor unit and the bookshelf speakers, which sound a bit dry.

And their distortion was lower that the system that sounded better and 10x the money.

Feelings are better than truth, so subjective and non repeatable tests in my view are problematic. But they are interesting to read.


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## JCsAudio (Jun 16, 2014)

It’s all totally subjective Holmz, measuring with test tones and measuring distortion plots is great and helpful in understanding what might sound good but in the end we use this equipment for recreating music and so using our ears in subjective testing is in my opinion the best test. The more people who listen and agree for any given blind test, the better and more believable the results. Because it’s all subjective, there will always be those who do not agree with the group/majority but we all have to start some place, especially those of us like me with modest means who cannot go out and buy $1000 amplifiers like it’s just another cable bill, lol.


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## Holmz (Jul 12, 2017)

Good luck. They are good reads and some truth comes out.
All the best!


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## Mullings (Jan 31, 2016)

It’s funny but this morning I went in my garage to look for a ring for a 556u “only alarm guys knows what this is” and walked pass 6 new kenwood reference amplifiers, 2 arc xdiv2 a Zed leviathan, not sure how many jl hd amps at least 6 about the same amount of Rockford fosgate plus more before I got to the alarm section and I said to myself “ how stupid can u be to think that all amps sounds the same?” I’m using McIntosh amps and had a really hard time finding something more transparent till I heard bill’s fj cruiser and Josh’s versa. don’t tell me that they would’ve sounded the same with any other amp cuz I’ve worked with jl, amps all my car audio career and in any blind fold test with any speaker and radio you use, I will tell you exactly what series of jl amp is being used 100% of the time.


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## SkizeR (Apr 19, 2011)

That versa is something else for sure

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## Rainstar (May 22, 2017)

i know someone with a giant table of amps to shootout too, but that guys busy....


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## SkizeR (Apr 19, 2011)

Rainstar said:


> i know someone with a giant table of amps to shootout too, but that guys busy....


he may have been messing with some of them in his spare time


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## JCsAudio (Jun 16, 2014)

Rainstar said:


> i know someone with a giant table of amps to shootout too, but that guys busy....


I’m guessing he is a young guy who lives 3 hours from me and has a cat for an avatar. . Since he is so young, I’m betting he has no kids and tons of free time as a result.


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## SkizeR (Apr 19, 2011)

V8toilet said:


> I’m guessing he is a young guy who lives 3 hours from me and has a cat for an avatar. . Since he is so young, I’m betting he has no kids and tons of free time as a result.


hes probably a kid trying to figure out life while balance starting a business, expanding said business, hiring an employee who may or may not be active in this very thread and generate work for said employee, getting jobs done, and make time for a nagging girlfriend. There will have to be a full on man hunt to find free time


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## DavidRam (Nov 2, 2014)

SkizeR said:


> hes probably a kid trying to figure out life while balance starting a business, expanding said business, hiring an employee who may or may not be active in this very thread and generate work for said employee, getting jobs done, and make time for a nagging girlfriend. There will have to be a full on man hunt to find free time


Not to mention chatting on diyma...


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## SkizeR (Apr 19, 2011)

DavidRam said:


> Not to mention chatting on diyma...


shush. im trying to get work done lol


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## DavidRam (Nov 2, 2014)

Lol... Me too


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## Mullings (Jan 31, 2016)

?, I wonder who’s that person.


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## Rainstar (May 22, 2017)

SkizeR said:


> and make time for a nagging girlfriend.

















Mullings said:


> ?, I wonder who’s that person.


that person has access to a 100A powersupply, one of the best 3-way speakers, 
and some high end amps that even Matt Hall did not test. His only downfall was to ever have to deal with a lunatic like me


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## SkizeR (Apr 19, 2011)

Rainstar said:


> His only downfall was to ever have to deal with a lunatic like me


quote of the ****ing century :laugh:


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## JCsAudio (Jun 16, 2014)

:speechless::snore::disappointed:


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## JCsAudio (Jun 16, 2014)

Ran some more tests today with a DLS CCi44 amplifier. The less powerful CC44 brother to this amplifier was one of the top performing amplifiers in the high value shootout, so I grabbed one from ANS so I could test it for myself. I set up the test bench in the same manner as before, only this time I rigged everything so I could switch them back and forth even faster than before. I also summoned my 12 year old daughter along with my former judge, my wife, to be the judges in a blind A vs B test. My daughter may not have experienced ears but she has sensitive new ears that can hear things we older folk have lost. The DLS went up against my former champion, the Alpine 3448 from above in a blind A vs B test where the judges could ask me to switch them back and forth as many times as they needed. They also each went alone at first so that none could influence the others opinion and it was interesting that they both came up with basically the same conclusions and notes. 

Here are some of the notes my 12 year old daughter took for amplifier #1 DLS and Amplifier #2 Alpine: 

DLS, sound travels to my ears different. Echo and voice stronger than background music. Bass and voice sound good and firm. Voice and echo much stronger. Better vocals and stronger sound separation and can travel better. background music clear and more balanced sound.

Alpine, Background music stronger. Echo and voice strong still. Echo is more pronounced. Bass is stronger and is stronger than background or voice.

My wifes notes were:

DLS, stronger vocals. sound separation better. Background more clear. More balanced sound.

Alpine, More detail in vabrado of voice. Bass is stronger. Bass muddy's up the vocals. Vocals where not as strong or prominent as the DLS (amplifier #1). 

I was standing behind the speakers but I also noticed stronger bass from the Alpine but also the DLS seemed to have a smoother more balanced sound. I measured them with my microphone and pink noise in REW and the Alpine did show a stronger bass with the DLS having a stronger top end. I leveled match the gains using my microphone as best I could so they both played the same level at 500 Hz to within .1 db. I lost those screen shots because my computer crashed so I will try and remeasure them and post that here. When asked which amplifier they preferred they both said the DLS sounded better overall. Up until this point the Alpine has won in every blind test but this time it lost by a slim margin to both judges. 

Next up will be my Rockford Fosgate Power t600-4. I already had the RF hooked up and did some listening against the Alpine and DLS myself and its going to be close, but we shall see. Once that one is done, I will be testing my Pioneer D8604. It will be interesting to see how the Pioneer D8604 does because its a modern budget class D amplifier. I also have a Zapco ST 2xSQ on the way to go up against the Alpine 3548 and DLS. 

More to come so stay tuned!


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## preston (Dec 10, 2007)

Thanks for posting. Always interesting to read these kinds of comparisons.


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## JCsAudio (Jun 16, 2014)

Ok, so I asked my 8 year old son to do the test. He stated the following about the differences between amplifiers when I asked him after listening to each amplifier about three times:

Amplifier #1 (DLS) more high pitched and better bass. Bass is louder.

Amplifier #2 Has a lower and higher pitch.

When I asked him which one he thought sounded better he said amplifier #1 (DLS). Remember, he's only 8 but he is brutally honest and has no clue why I'm even doing this so his response I would say is even less biased. 

I then did the listening test myself to see if I could hear a difference and I really could not. I thought maybe the Alpine sounded a little less natural but I also knew which one was playing so the psychological factor may have been skewing my thoughts. 

I then measured the responses with my microphone and REW between the two and found that the DLS was playing 3/10's of a db louder so I have to throw all these results out and do the test all over again. I also see that they play exactly the same across the board from low to high whereas before I saw different responses in the lows and highs. This time though I measured the responses so that I was standing behind the speakers and completely still so that any reflected sounds would not skew the response. Last time I was standing next to the microphone and off to the side of the speakers so if I moved even a little I could have changed the reflected sounds and thus the response. 

The first graph is as they were tested and red is the DLS and green the Alpine. The second graph is after I re-adjusted the gain on the DLS down some so they are exactly matched now and blue is the DLS and green the Alpine. I will redo the test and post the results later.


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## JCsAudio (Jun 16, 2014)

Ok, I redid the tests again with the correctly level matched gains the same way as before with my wife first and then my daughter second. Amplifier #1 was the DLS and Amplifier #2 was the Alpine and they didn't know which one was which. 

My wife stated for amplifier #1 vocals sound clearer and sounds like vocals are more separate and distinguishable. Hits the vocals better.

My wife said amplifier #2 Bass is stronger, vocals fine but feel like when all the instruments come in they are bumping into each other and there is less separation. 

Wife said #1 sounds better so DLS wins again.

My daughter stated amplifier #1 sounded a lot like the person was in front of you and perfect amount of bass and background music and voice. Voices were very clear and could hear every little detail.

My daughter stated amplifier #2 voices clear but sounded more staticy and wasnt as clear. There was less detail and not as balanced.

Winner - DLS.

So now I'd like to know if I should compare the RF to the Alpine or put it up against the DLS since the DLS clearly keeps winning the comparison?


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## compuwiz1937 (Jun 5, 2017)

I’m interested to see how the Zapco stacks up.


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## JCsAudio (Jun 16, 2014)

compuwiz1937 said:


> I’m interested to see how the Zapco stacks up.


Me too! 

Do you guys want me to put the Zapco up against the Alpine first or the DLS and should I put the Rockford Fosgate Power t600-4 up against the DLS first or the Alpine? 

I'm leaning towards keeping it all the same with each new contender against the Alpine 3548 at first and then run up the winners from that group against each other after that. Its just going to take much longer if I do that because I have limited time. 

If anyone nearby has an amplifier that they want to put up against any of these amplifiers I have in this test and also be a judge than feel free to ask.


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## miniSQ (Aug 4, 2009)

While i am sure your small children and wife can discuss what they hear.

I wonder what would happen if you were to set it up so you played Amp A, and then Amp B, and then added in an X factor...either amp A or B or even C. With one of the amps being the DSL.

Do you think they could reliably choose which one was the DSL repeatably?


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## Hillbilly SQ (Jan 26, 2007)

I just now figured out who you used to be. Why the name change? lol. 

Good read btw.


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## JCsAudio (Jun 16, 2014)

miniSQ said:


> While i am sure your small children and wife can discuss what they hear.
> 
> I wonder what would happen if you were to set it up so you played Amp A, and then Amp B, and then added in an X factor...either amp A or B or even C. With one of the amps being the DSL.
> 
> Do you think they could reliably choose which one was the DSL repeatably?


If I did an A vs B but didn't tell them there was a C and switched it up I would say they would not reliably pic the DLS but I'm not completely sure about that either. They don't know which amplifier is playing and I know they both do not care which amplifier is playing because they just do not care about this stuff like I do. I believe the results are reliable for that reason. I could take any combination of amplifier and play A vs B and they wouldn't know any different except for what their ears tell them.

The other factor is that these amplifiers are so close that I think in the end anyone would be happy with either one of these in the noisy environment of a vehicle. Its not like you hear one and then the other and immediately say to yourself there is a big difference. Sometimes my wife and daughter have to go back and forth several times before they make a choice and comment on #1 vs #2 and so far they have picked the DLS every time. Sometimes the DLS is #1 and Sometimes the DLS is #2 also so they cant assume that either. After I level matched and redid the test with three different people in three completely different tests they all picked the DLS as the winner and they all made similar comments about the sound. I was struck by the comments from all of them being so similar about the characteristics of the sound, which tells me they are being honest and they are hearing things that are attributable to the amplifiers themselves. 

I think this answers my earlier question and so I will put the DLS up against the next contender and keep doing that until it loses.


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## JCsAudio (Jun 16, 2014)

Hillbilly SQ said:


> I just now figured out who you used to be.
> 
> Good read btw.


Shush, you no nothing my friend. 

BTW, I enjoyed your comparison between the 2-1/2” Morel midrange and AF GB25. That was a good read. 

Next contender going up against the DLS shown below. A Zapco ST SQ should be here before the weekend to take on the winner of that challenge.


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## WinWiz (Sep 25, 2013)

Thank you for spending time doing and posting these test ?
Are you also going to test the Pioneer D8604?
I have purchased two of these. My decision to purchase was only based on price, listed specs and a single rms power test I found on YouTube. Because of my final exams I don't have time to install the new amps right now so I'm really interested in any info about these amps.
Do you believe the D8604 outputs 2x500 rms watts bridged at 2 ohms?


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## WinWiz (Sep 25, 2013)

Maybe this is stupid but I'm thinking maybe tests done using a phone as source isn't really representative of these amps typically usage? I Know the music is lossless but the phones DAC probably isn't as high quality as a good headunit?
I know almost nothing about the electronics used in amps but I am guessing some designs might work better with the weak signal from a phone? I believe digital amps converts the analog input to a digital signal. If the phones dacs converts from digital to analog at a certain frequency (like 44khz) this might favor amps doing the reverse conversion at the same frequency? Because I don't know what's really inside a class D amp I could be be totally wrong about this, just seems logic to me that digital conversions from 44 to 44khz might sound better than conversions from 44 to 48 khz? If so it's giving the amps operating 44khz, or other frequencies that's matches or multiplies the inputs dac frequency an unfair advantage.
This is just a thought I got, and in no way meant as criticism of you great work ?


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## JCsAudio (Jun 16, 2014)

WinWiz said:


> Thank you for spending time doing and posting these test ?
> Are you also going to test the Pioneer D8604?
> I have purchased two of these. My decision to purchase was only based on price, listed specs and a single rms power test I found on YouTube. Because of my final exams I don't have time to install the new amps right now so I'm really interested in any info about these amps.
> Do you believe the D8604 outputs 2x500 rms watts bridged at 2 ohms?


That is the plan hopefully this weekend if time allows and I think there is enough interest in it from other members? Ryan from Budget Gem or bust and I think it was Big D wiz got some impressive numbers on thier dyno’s from the D8604 and D8605 amplifiers. It’s definitely good for at least 100 wpc in my opinion. 



WinWiz said:


> Maybe this is stupid but I'm thinking maybe tests done using a phone as source isn't really representative of these amps typically usage? I Know the music is lossless but the phones DAC probably isn't as high quality as a good headunit?
> I know almost nothing about the electronics used in amps but I am guessing some designs might work better with the weak signal from a phone? I believe digital amps converts the analog input to a digital signal. If the phones dacs converts from digital to analog at a certain frequency (like 44khz) this might favor amps doing the reverse conversion at the same frequency? Because I don't know what's really inside a class D amp I could be be totally wrong about this, just seems logic to me that digital conversions from 44 to 44khz might sound better than conversions from 44 to 48 khz? If so it's giving the amps operating 44khz, or other frequencies that's matches or multiplies the inputs dac frequency an unfair advantage.
> This is just a thought I got, and in no way meant as criticism of you great work ?


Class D amplifiers are still analog amplifiers, just with faster switching transistors than Class A/B and they use a series of filters to remove the switching noise that results from that faster switching. It’s more complicated that that but to keep the explanation simple, that is the major difference. Class D designs are also more difficult to get right but I believe Pioneer corporation has the experience to get them right. I have three of their amplifier designs and love them. Given that the input source is the same for both amplifiers I believe the quality of the DAC in my iPod (generation 7) is fine. I can barely hear the difference between a 250 bit rate MP3 and lossless so I highly doubt you’ll hear the difference in the DAC. Too keep this on topic I do not want to get into any debates about DAC’s.

It’s weird that I’m not getting email notifications for these threads.


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## JCsAudio (Jun 16, 2014)

I've had the Rockford Fosgate Power t600-4 set up for a few days now, just waiting for some judges to become available. I measured the response in REW to verify a few things such as playing on an even level and noticed that the Rockford Fosgate has a different response compared to all the rest. It measures with a higher level in the treble and bass octaves but is matched in the middle octaves. I measured it several times just to verify and it measures the same every time. This is what I was seeing when I measured the RF against the DLS, and the Alpine before I lost those graphs due to my computer crashing.

I’ve been doing my own listening sessions against these two and I think the DLS sounds better still but my listening impressions are not reliable because I know which amplifier is playing so I’m curious what the blind test will come up with. I will start with the RF in the test just to switch things up but again the judges do not know what is play or even which two amplifiers are playing. The RF is shown in red.


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## JCsAudio (Jun 16, 2014)

Did an initial blind test with my wife and she closed her eyes while listening. I played the song Natural by Imagine Dragons and she said to me "I cant tell which one is the Alpine". I asked her to tell me just which one she thought sounded better and why and she said "I cannot tell right now". "I will have to try again later". I started out with the Rockford Fosgate t600-4 and then the DLS. I also pulled the Pioneer D8604 from my truck and have a new Zapco ST SQ standing by as well for the next few tests. 

So far the RF seems to be closer than I initially thought even though it measures the most different in the RTA. More testing to come tomorrow.


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## WinWiz (Sep 25, 2013)

Is the amp connected to iPhone through apples lightning audio connector?


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## JCsAudio (Jun 16, 2014)

Ok, ran the test with the Rockford Fosgate against the DLS CCi-44. First of all the RF has almost twice the real RMS power as compared to the DLS so please keep this in mind when you read the notes presented by my wife, daughter, and son. I think my daughter may have been picking up on this in terms of headroom with the Rockford Fosgate, maybe. 

In this test the RF was amplifier #1 and the DLS amplifier #2 and I started out the test with Amplifier #1 for all the judges. All of the judges had a harder time this time deciphering which amplifier was the better sounding amplifier and all of them had to switch back and forth more often this time compared to the other tests. These amplifiers are very close in sound.

Yesterday I tried the test with my wife but she gave up after the first audition and said I can’t really tell right now. She was also tired so her patience wasn’t all there either. I tried the test myself and also had a hard time telling but thought the DLS was just a tad smoother and more realistic but my thoughts were also clouded by the fact that I knew which amplifier was playing so my thoughts are not reliable. Also keep in mind this is a blind comparison test so when one judge says one is not as clear as the other, it’s in reference to the other in that test only. Just because they say it’s not clear doesn’t mean it’s not actually clear but that there is a perceived difference in reference to the other in that test. 

*Amplifier #1* is the Rockford Fosgate t600-4 rated 4x100 wpc but often puts out 50% more.
*Amplifier #2* is the DLS CCi-44 rated 4x85 wpc and likely does about rated. 

_*Wife’s notes/comments:*_

*Amplifier #1* “vocals not as crisp or clear. Bass seems stronger. Volume in vocals seemed louder but not as clear. When everything in the song came in the song it was as if it was an assault of sound but I didn’t get that feeling with amplifier #2”. 

*Amplifier #2* “I think it has better individual sound quality to it and better separation of sound. It has an overall more balanced sound. The difference is noticeable but small and hard to tell at first. 
I asked her which one she preferred and she said amplifier#2.

_*Daughter’s notes/comments:*_

*Amplifier #1*, “at first both sounded the same. After listening more I think amplifier #1 is clearer when the singer started yelling in the song. The vocals were clearer and they have better balance overall”.

*Amplifier #2* “It sounds less clear when the singer started yelling in the song compared to #1. I don’t think it’s as balanced as #1”. 
I asked her which one she preferred and she said amplifier#1

_*Son’s Comments:*_

*Amplifier #1* “It has more static in the sound but I think it has better overall sound. It sounds better with the background parts of the music when all playing at once”.

*Amplifier #2* “It has less background sound but both are really close but it’s hard to tell”. 
I asked him which one he preferred and he said amplifier#1

So there you have it. The DLS wasn’t a clear winner this time. The Rockford has an advantage in the treble and bass as measured with the microphone which might be perceived as better by younger people compared to my wife’s more experienced ears. My wife still prefers the natural sound of the DLS. One thing is for sure is that these are so close that there isn’t really a clear winner here. I’m going to call this one a tie for now.

Next up, the DLS is going up against the Pioneer D8604. This is going to be interesting. Will it do as well as my older designed ICE Power Class D Pioneer PRS D4200F or better? Will this budget class D do well against a good class A/B design? Stay tuned to find out.


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## JCsAudio (Jun 16, 2014)

WinWiz said:


> Is the amp connected to iPhone through apples lightning audio connector?


No, it is connected through the headphone jack into a phono to RCA adapter and directly fed into each amplifier. The lightening cable would have to go into a pre amplifier to work that way as that is a pure digital signal and would use the DAC in the head unit vs the one inside the apple iPod. I'm using the same input for each amplifier with the same exact cables so there is no difference there.


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## SlvrDragon50 (Apr 10, 2017)

JCsAudio said:


> Ok, ran the test with the Rockford Fosgate against the DLS CCi-44. First of all the RF has almost twice the real RMS power as compared to the DLS so please keep this in mind when you read the notes presented by my wife, daughter, and son. I think my daughter may have been picking up on this in terms of headroom with the Rockford Fosgate, maybe.
> 
> In this test the RF was amplifier #1 and the DLS amplifier #2 and I started out the test with Amplifier #1 for all the judges. All of the judges had a harder time this time deciphering which amplifier was the better sounding amplifier and all of them had to switch back and forth more often this time compared to the other tests. These amplifiers are very close in sound.
> 
> ...


Looking forward to it. I thought my complaints with my system were due to the speakers, but I think it might actually be due to my D8604. Still really love the amp for how cheap it is. I won't say any of my thoughts until after you post your review though!


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## JCsAudio (Jun 16, 2014)

Got the Pioneer D8604 hooked up and level matched to the DLS. Looking at the REW measurements they track slightly different but closer than the Rockford Fosgate did to the DLS. DLS is green and Pioneer is blue. 









I did some listening tests on my own but I'm not going to say right now what I think I can hear. Should be able to get this done tomorrow hopefully.


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## JCsAudio (Jun 16, 2014)

Just realized that there isn't enough contrast between green and blue so I changed the colors.

DLS is blue and Pioneer D8604 is purple.


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## SlvrDragon50 (Apr 10, 2017)

JCsAudio said:


> Just realized that there isn't enough contrast between green and blue so I changed the colors.
> 
> DLS is blue and Pioneer D8604 is purple.
> 
> View attachment 242999


Do these graphs reveal anything about the amplifiers themselves? Not too sure how to interpret them. Or is it just to show the two amps are matched against each other.


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## JCsAudio (Jun 16, 2014)

SlvrDragon50 said:


> Do these graphs reveal anything about the amplifiers themselves? Not too sure how to interpret them. Or is it just to show the two amps are matched against each other.


Initially I did them to show that they are level matched but if you look at them on a larger screen there are small differences at different frequencies with the RF having the biggest differences. Are these perceptible, IDK for sure but they are picked up by the microphone. When I measure them I keep everything the same and I measure them within minutes of each other in a controlled environment and I stand behind the speakers in the same spot and stand still during the measuring so not to influence the reflected sounds in the room.

In my opinion the differences between the DLS and Pioneer shown should not be perceptible.


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## SlvrDragon50 (Apr 10, 2017)

Cool! Looking forward to hearing your thoughts. I've been looking at possibly replacing my Pioneer, but I don't think I'm really going to see much improvement other than going to a 6 channel and making my tweeters active.


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## WinWiz (Sep 25, 2013)

The D8604 is so cheap, I guess pioneer had to cut some corners. In Denmark retails for 195 USD including tax and shipping, so that's as cheap as the overrated nobrand "Walmart" amps.
I only use my D8604 below 1600Hz. High frequencies is challenging for class D amp, so I hope the 8604 perform ok below 1600Hz.
Looking forward to your test results.


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## JCsAudio (Jun 16, 2014)

SlvrDragon50 said:


> Cool! Looking forward to hearing your thoughts. I've been looking at possibly replacing my Pioneer, but I don't think I'm really going to see much improvement other than going to a 6 channel and making my tweeters active.


I’m going to agree with that conclusion 



WinWiz said:


> High frequencies is challenging for class D amp, so I hope the 8604 perform ok below 1600Hz.
> Looking forward to your test results.


I’ve tested a bunch of class D amplifiers now and I’m going to say that is a misnomer at least for today’s modern class D amplifiers. My Pioneer PRS D4200F did really well in my tests and it’s a 10 year old design class D . One of the worst performers in my tests so far is a Class A/B. There are some really good class D designs out there with companies like MMATS leading the way. Keep in mind the DLS is roughly a $500 Class A/B design and if I had a roughly $500 class D design to pit it against than we might have a real match.


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## Holmz (Jul 12, 2017)

JCsAudio said:


> Just realized that there isn't enough contrast between green and blue so I changed the colors.
> 
> DLS is blue and Pioneer D8604 is purple.
> 
> View attachment 242999


If the "clear sound" is a description of lower distortion, then is doubtful that much would show in REW.
One pretty much needs to measure the output against the input to see what is being added, or what is not coming through.

Then once the distortion gets below the speaker distortion, then noticing the amplifier, even using digital (math based) metrics, becomes a bit hard to accomplish. Basically the amplifier is cascaded with speakers distortion, reflections, etc...

On the other hand, the fact that they noticed it was clearer starts to gain relevance with more people liking it... even if one cannot quantify what it is that the amplifier is doing (or not doing)... it just is hard to tell the mechanism of what makes it better.

I am not even sure if know if either amp was clipping.


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## JCsAudio (Jun 16, 2014)

Holmz said:


> If the "clear sound" is a description of lower distortion, then is doubtful that much would show in REW.
> One pretty much needs to measure the output against the input to see what is being added, or what is not coming through.
> 
> Then once the distortion gets below the speaker distortion, then noticing the amplifier, even using digital (math based) metrics, becomes a bit hard to accomplish. Basically the amplifier is cascaded with speakers distortion, reflections, etc...


 Agreed Holmz, we are mostly just doing this for fun and using our ears as we would for music in this test. 



Holmz said:


> On the other hand, the fact that they noticed it was clearer starts to gain relevance with more people liking it... even if one cannot quantify what it is that the amplifier is doing (or not doing)... it just is hard to tell the mechanism of what makes it better.
> 
> I am not even sure if know if either amp was clipping.


Agreed, the level I'm playing the music at I'm guessing is around 80-85 DB so I'm going to guess that this level should be within clipping of each amplifier or even the rising distortion before clipping. I should measure the SPL level with my SPL meter though and post it so you guys can know. My Daughter especially does not like the music loud. Good Points you brought here!

If clipping or rising distortion as I approach clipping is a factor than by that logic every amplifier that is 85 wpc or more powerful should do as good or better than the DLS. So far the Rockford Fosgate is almost twice as powerful and the rest have been less but also remember when I bridged that Alpine F240 that it didnt make any difference and still sounded the same. Also by this logic the Pioneer D8604 with over 100 wpc should avoid this distortion before the DLS and have more clear sound so we shall see. 

On that Rockford Fosgate (changing topic from this post) I realized last night that the increased treble and bass in the REW graph could be from the always on Punch EQ so I will have to check that to make sure.


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## Holmz (Jul 12, 2017)

JCsAudio said:


> Agreed Holmz, we are mostly just doing this for fun and using our ears as we would for music in this test.
> 
> 
> 
> ...


Seems like it is fun from here, and good for the kids too.


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## JCsAudio (Jun 16, 2014)

Ok, finally got my wife, daughter, and son to be the judges in the next test with the Pioneer D8604 and wrote down their comments after each listening test. I also asked them each the same question after they gave me their comments and that question was: Do you think #1 sounds better, #2 sounds better, or do you think it is a tie?

Amplifier #1 was the Pioneer D8604
Amplifier #2 was the DLC CCi-44.

*Son*
#1 has more bass than #2. #2 is more high pitched. 
Answer to question: Think it’s a tie.

*Wife*
#1 It’s very close! I like #1 but I can’t explain why. More bass but I do not always like that. 
#2 ending vocals seemed to not be as clear in song. 

Answer to question: I Likes both. They are very close. I say it’s a tie. #1 when everything is playing at once in certain things but sound can be overpowering at times. Vocals in the beginning are very clear with a quality sound to #1. With #2 there is slightly less depth to the vocals. #1 has a very clear sound when just the vocals are playing. 

*Daughter*
#1 sounded same/similar as #2 in last round (DLS was #2 in last round). Voice sounds like he is singing through a digital device and not direct to me. 
#2 Prefer echoing in the background and voice in #2. His voice sounds like it’s in front of me and the echo is around me. Sounds like he is singing into a good microphone. Has good sound. 

Question: close to being a tie but #2 slight advantage but also like #1. 

Looks like the Pioneer did better than everyone might have expected. Don't pay attention to my daughters comment about the digital sound as she has no clue about that stuff and she thought the Pioneer was the DLS in this round. I had to play each amplifier twice for each judge and could tell they were having a hard time making out any differences. The Pioneer D8604 is also the second most powerful amplifier in this test only to the Rockford Fosgate t600-4 so I’m starting to think that the amount of power and therefore headroom is having an effect on the dynamics of the song. The most powerful amplifiers are also the top three winners so far. I think I'll be putting the D8604 back into my truck as I've said before I like this amplifier very much. I think Pioneer's engineers did a good job designing this Class FD (class D) amplifier. I'm also convinced that class D is just as good as Class A/B for reproducing quality sound but with less heat and in a smaller footprint. The DLS heats up some during the twenty minutes or so of testing whereas the class D amplifiers do not even get warm.


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## JCsAudio (Jun 16, 2014)

I've got the Zapco ST-2X SQ strapped up, level matched, and ready to go. See how it compares in the attached REW graph playing pink noise. I also measured the DB level while I was performing the listening tests with the judges and the DB level was only around 78 db at about six feet from the speakers.

Zapco ST-2X SQ is green and DLS CCi-44 is red


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## WinWiz (Sep 25, 2013)

So the D8604 actually managed to compete with some of the more expensive amps. That's very impressive!
Yesterday I installed another D8604 in my car. It powers my dvc 12" sub (4+4 ohm) in bridged mode. It replaced an old Rockford Series 1 4600 amp. The old amp did run a little hot when I played bass heavy music. I mainly changed amp to lighten the stress on my cars electrical system. I think 3 amps is stretching the cabability of my Honda Civics stock generator and tiny battery.
So I'm pleased to read that my decision to purchase 2 pioneer d8604 amps wasn't stupid.
Once again thanks for doing these blind tests.


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## JCsAudio (Jun 16, 2014)

WinWiz said:


> So the D8604 actually managed to compete with some of the more expensive amps. That's very impressive!
> Yesterday I installed another D8604 in my car. It powers my dvc 12" sub (4+4 ohm) in bridged mode. It replaced an old Rockford Series 1 4600 amp. The old amp did run a little hot when I played bass heavy music. I mainly changed amp to lighten the stress on my cars electrical system. I think 3 amps is stretching the cabability of my Honda Civics stock generator and tiny battery.
> So I'm pleased to read that my decision to purchase 2 pioneer d8604 amps wasn't stupid.
> Once again thanks for doing these blind tests.


Not getting email notifications again for some reason. Don’t be afraid to use this amplifier for highs as well. It makes my AudioFrog GB10’s sound great. The average power consumption on music and running with a 4 ohm load is only 10 amps so you should be ok. You can always upgrade the battery to the biggest AGM (all glass Matt technology) battery you can fit. I buy my AGM battery’s from Advance Auto and they seem better or as good as the yellow top Optima I have in my CX5. The advantage to an AGM battery, which is still a lead acid battery but with tightly packed plates in a gel electrolyte, is they charge up faster, take vibration better, and take deep discharges better, and recover better over a regular traditional lead acid battery. They can help out in vehicles with high electrical loads for these reasons.


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## ckirocz28 (Nov 29, 2017)

JCsAudio said:


> AGM (all glass Matt technology)


Absorbent Glass Mat
But everything else you said was correct. I've never had an issue with Optima batteries, however, I'm using one XS Power D4900 (audio only) with plans to replace my Yellow Top (under hood) with a XS Power D3400. XS Power makes some damn good batteries.


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## WinWiz (Sep 25, 2013)

Only Battery's with a Max width of 5" (Japanese industry standard) fit my Honda Civic. So the only optima yellow top that would fit is the 38Ah. The OEM battery is 46Ah, so a yellow top wouldn't be an upgrade. Besides I have read about quality issues with yellow top batteries, and they are very expensive in Denmark.
I know it will require extensive repairs to make my Civic pass the next wot expection in December, so sadly I will have to scrap my civic. Therefore I don't want to invest a lot of time or money in my car.


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## LBaudio (Jan 9, 2009)

compare RF to both other amps - DLS and Alpine


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## JCsAudio (Jun 16, 2014)

ckirocz28 said:


> Absorbent Glass Mat
> But everything else you said was correct. I've never had an issue with Optima batteries, however, I'm using one XS Power D4900 (audio only) with plans to replace my Yellow Top (under hood) with a XS Power D3400. XS Power makes some damn good batteries.


Whoops, you are correct. I knew I was somewhat in the ballpark but I was winging it. :laugh:



WinWiz said:


> Only Battery's with a Max width of 5" (Japanese industry standard) fit my Honda Civic. So the only optima yellow top that would fit is the 38Ah. The OEM battery is 46Ah, so a yellow top wouldn't be an upgrade. Besides I have read about quality issues with yellow top batteries, and they are very expensive in Denmark.
> I know it will require extensive repairs to make my Civic pass the next wot expection in December, so sadly I will have to scrap my civic. Therefore I don't want to invest a lot of time or money in my car.


I hear very good things about XS Power batteries. Looks like you're on the right track. 



LBaudio said:


> compare RF to both other amps - DLS and Alpine


Please look back at post # 31 and 35 where I compared that RF to the DLS.


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## JCsAudio (Jun 16, 2014)

Okay, I was able to get my daughter to do the judging but I seem to have lost the notes I took from her on Saturday. I'm not having much luck with time and the wife isn't very receptive to doing one more test so it might be a little longer, plus my son has three games this week. My daughter auditioned the Zapco ST 2X SQ three times with one song and then two times with another song before making a decision. She liked both for slightly different reasons but in the end chose the DLS over the Zapco mainly because of the very slight increased clarity in vocals during demanding levels within the song, which I'm attributing to the DLS for having more power. It was really close and there is no clear winner here so far. Remember this test is blind and she did not know which amplifier she was listening to; only that there are two and one is #1 and the other is #2. 

Some of the things I’m starting to think are that within the distortion and clipping limits of the amplifiers they basically sound the same. Some differences could be attributed to phase differences as well although I don’t fully understand how yet. With these contenders in this price group it doesn’t seem to matter whether they are class A/B or Class D and the Pioneer D8604 Class D surprised me. Some of the things you do get with more expensive amplifiers are higher quality components and features and less noise floor. With the DLS for example, the switches and pots seem to be of higher quality and on the RF Power, the terminal clamps are nice. The winners in this group seem to be attributed to just having more power vs anything else I can attribute it to, although without objective testing I’m only guessing. Still the subjective blind listening tests show there isn’t much difference in sound among these amplifiers and it certainly wouldn’t be a factor in the noisy environment of a vehicle in my opinion. 

In the first shootout I used a power supply that was barely adequate for the amplifiers I was testing. Still the power hungry Alpine Class A/B 3548 sounded noticeably better than the others, especially over the Alpine MRP F240, and even I could hear that difference. In this group of testing I’m using the equivalent of 110 amps of power supply (two APS 55 ganged together) at 14.2 volts so I’d like to strap up that Alpine MRP F240 to these power supplies and test it against the DLS to see if I can again clearly hear a difference. If I can’t repeat those results than I’m going to attribute the MRP F240 losing to the lesser power supply not supplying enough power in the first test.


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## SlvrDragon50 (Apr 10, 2017)

Just saw the reviews on the Pioneer. Don't feel as obligated to upgrade my Pioneer anymore! That Mosconi Pico in the classifieds is calling my name though to add 2 more channels and make my tweeters go active.


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## JCsAudio (Jun 16, 2014)

SlvrDragon50 said:


> Just saw the reviews on the Pioneer. Don't feel as obligated to upgrade my Pioneer anymore! That Mosconi Pico in the classifieds is calling my name though to add 2 more channels and make my tweeters go active.


To bad you are not close because we could put that thing to the test.


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## SlvrDragon50 (Apr 10, 2017)

JCsAudio said:


> To bad you are not close because we could put that thing to the test.


Hah, well luckily someone else snatched it up before I could impulse buy it! I am thinking of making a move to a simple 6 channel amp and then giving my dad my Pioneer.


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## JCsAudio (Jun 16, 2014)

Well, finally got my wife to finish the listening test between the Zapco ST 2X SQ and the DLS CCI-44 and she pretty much easily picked out the DLS over the Zapco after going back and forth three times as the better sounding amplifier. 

For the Zapco (amplifier #1) she said the vocals seemed brighter but not as crisp. She said things got a little muddy when the singer was singing and all the instruments were playing all at once. The song was Believer by Imagine Dragons in lossless file format.

She said about the DLS (amplifier #2) that she liked the separation of sound when everything was playing at once. She said everything in the song is very definite and well defined and that there is more detail in the small differences when everything is playing together. She explained it in many different ways but basically kept saying how well the music was well defined, that she could hear all the little tiny details especially when everything was playing together during demanding passages within the song.

Honestly I thought the Zapco would have been closer but she pretty much zeroed in on it pretty quickly. I think the Pioneer D8604 class D was more of a challenge than anything else in this testing. 

I also noticed how much hotter than DLS gets than the Zapco or any other class A/B in this test. I think its more class A biased maybe. It was 99 degrees within 20 minutes of standing by when the Zapco was 79 degrees and the air temperature was 69 degrees. 

I will hook up the Alpine MRP F240, which was the class A/B that had the worst sound in the first test and see how well that does this time. If it loses horribly like it did before than I'll know the tests are repeatable. If it becomes a situation where its hard to tell than I have some explaining to do.


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## JCsAudio (Jun 16, 2014)

MRP F240 vs DLS level matched to within .2 db in favor of the Alpine. We shall see what happens soon.


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## JCsAudio (Jun 16, 2014)

This test consisted of an Alpine MRP F240 bridged for 100 wpc (amplifier #1) vs DLS CCi-44 (amplifier #2) using two channels at 85 wpc. 

Well, the Alpine MRP lost big time to the DLS so much so that I even noticed it from standing behind the speakers. It was a noticeable difference. I even bridged the MRP F240 so that it was giving 100 watts per channel so that the power would be in the Alpines favor but that obviously didn’t help and the Alpine is a class A/B so no blaming class D on this test. My wife told me to turn it off after just one play on each one and said amplifier #1 was garbage, which was again the Alpine MRP F240. She stuck her tongue out and said she didn’t even want to listen to it again, it was so bad by comparison to the DLS (amplifier # 2).

So that concludes this testing. I’m out of amplifiers and money that I want to spend on this testing. Is there a difference in sound between amplifiers, yes but with newer modern amplifiers the differences are very small when played within their limits. Does class A/B sound noticeably better than class D; I don’t think so at this price point. All my class D amplifiers actually did very well in this testing. What makes one amplifier sound better than another; too many things to say. Differences in sound could be attributable to phase differences, power differences, or the quality of the power supply within the amplifier itself. I think today’s amplifier technology, whether class A/B or class D, is very good and it really depends on the design of the amplifier more than the class itself. I also am starting to think the Zapco SQ series is a bit over rated myself. It must be that SQ marketing thing they played up bid time. It’s not bad by any means but it’s not up there with the less known DLS as far as I’m concerned.


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## tyroneshoes (Mar 21, 2006)

Nice interesting post. Im doing something very similar and Ive been through about 25 amps or so comparisons, except for using the on axis bookshelves full range, I also try each amp on a sub. 

I will say that I also grabbed the Zapco Studio 2x SQ from world wide for $65 as well. I was also somewhat underwhelmed by this amp as well. The amp I was comparing to a/b was a zapco studio 100 from 93 so it was very similar power. It was fine, but no where as clear and detailed as the older zapco, or the new full range class d amps from zapco. It was very easy to swap my into my car playing tweeters from 2.5 up and it was not as nice as the old zapco studio 100 so I am not using it and put the old studio back in. 

The 4 channel st-402 sq class d sounds as good as my favorite amps and superior to the a/b sq amplifier to me and the others Ive tried. However, its not a bad amp, just not outstanding.

I will eventually get back to posting and write down all the notes on the various amps Ive tried. I will briefly share my favorite amps I have a/b tested on full range high end booksheves and the JL cp108 micro sub which is my testing sub I also listen to in tests. So typically 2.1 but if the amp is a 2 channel, I run it full range for a few work days, then move it to the sub and put another 2 channel on the full range bookshelves. 

Overall the amps that have impressed us most are:

Zapco studio 100 and 300x from 92-94
Current Zapco ST-204 SQ class d(in car now)
Mosconi Zero series
Sony ES 2100g (90s)
Alpine PDR v75 (5 channel)
Kenwood xr400-4 class d 
Kenwood KAC-X4r class d (dsp turned off)
Audio Art 200.2
Rockford P400-2
Audio Designs 60.4
Sony xm-gs4
MTE Audio MGS2500.4 micro class d (malaysian brand)



The amplifiers that no one really liked were 
Kenwood Ps200t (90s)
Soundstream TN4.900D (first version with fuses)
Soundmangus sk600.4 (both the above are Epsilon) 
Arc Audio Mini 4.150 class g/h
Phoenix Gold rx400.4

All the above had noise floor issues. 

The pioneer d8604 was a fine amplifier as well and great deals. Most amps dont sound significantly different and if theres nothing remarkable, I didnt mention it. I have lots of amps around and tried many over the past 3 years I have been testing these while working. 

I think now the Full range class d's from Both Kenwood and Pioneer are great budget choices and sound very similar to amps costing lots more. The pioneer, kenwood, and polk audio PA20002 all got the same score on full range. Same score as the Arc XDI. 

I prefer Kenwood to pioneer regarding full range class D (treble response) but I would say they are very similar in "SQ" to the Zapco Studio SQ a/b series. Just 60 watts can run ut of steam fast if not on mid/tweeters. Zapcos F/R class d's sound much more enjoyable to me than the less expensive a/b SQs. 

My personal preference is class a/b on the tweeters as I get an "airy" type feeling with good ones. 

On the sub, the highest rated amps was the 

Rockford p300-1 and p400-2
Alpine MRD-M500
Alpine PDR-m65
Zapco Studio 300x
Zapco st 204d sq

In general, sub cone control and overall sound was tested mainly subjectively. On a sub, the ones that didnt sound good full range (ex. epsilon) worked fine on subs but not standouts. However, Im listening indoors with vifa ring radiators on axis so home vs car may be different, but thats more power related.

Overall, Id say all amps do sound different but it is very small differences between them. I agree with major differences are the pots used, rcas used and cosmetics when dealing with respectable companies. 

But to me the biggest differences is the on board dsp on the RFs, Kenwood and alpines that make the biggest difference. With an external DSP, the differences are much smaller. Brand preference comes into play mostly. The Current excelon and pioneer full range class Ds are excellent values. 

Id love to see what you think about comparing the current Kenwoods class d f/r to the Pioneer. 

The fact that you can get 1000+ watts 5 channels from both companies under 200 now is unreal.


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## jimmyjames16 (Dec 12, 2006)

tyroneshoes said:


> I think now the Full range class d's from Both Kenwood and Pioneer are great budget choices and sound very similar to amps costing lots more.
> 
> The Current excelon and pioneer full range class Ds are excellent values.


Hey Tyrone.. I have to agree with you with the Kenwood Excelon class D's .. they sound incredible and if not better than the JL HD or Arc XDi amps I had prior. 

I actually took your advice on these a few years back and didn't expect them to sound so good because they were first off a "Kenwood" .. and their lower price mark just seemed like another low grade amp that would either blow or sound crappy overall . That wasn't the case at all. The XR400-4 sounded a bit sharper and stronger than it's predecessor - the XR-4S .. it was a bit more cleaner and ballz-ier. 

I would have stayed with that setup but Gordon was building my Compact Four Class A at the time and I could't wait to install and hear it. My JL HD just never sounded right and was very frustrating trying to dial it in correctly. The Arc Xdi did sound better .. but lacked some depth and instrumentals that I know were there but seemed to fade out in the distance. 

The Excelon was right up there though.. I was even contemplating getting the XR401-4 just for ****z & giggles to check out the new Hi-Res features and compare it ot my Genesis sytem setup and see if it was all worth it by upgrading my alternator, batteries, etc.

Do you believe that the Zapco ST-204D SQ would be the best Class D F/R on the market today.. given your listening experience?


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## WinWiz (Sep 25, 2013)

I recently replaced 2 vintage Rockford amps with 2 pioneer 8604 amps. The new pioneer amps seem very sensitive to elctronic noise from my mobile phone. If I don't enable flight mode my speakers plays weird unpleasant sounds whenever my phone's connection changes from one mast to another.
Am I the only one noticing this?


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## SlvrDragon50 (Apr 10, 2017)

WinWiz said:


> I recently replaced 2 vintage Rockford amps with 2 pioneer 8604 amps. The new pioneer amps seem very sensitive to elctronic noise from my mobile phone. If I don't enable flight mode my speakers plays weird unpleasant sounds whenever my phone's connection changes from one mast to another.
> Am I the only one noticing this?


Uhhh. That shouldn't happen. I'd think something is up with the installs. Probably the grounds.


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## WinWiz (Sep 25, 2013)

Maybe I should try grounding my phone...


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## JCsAudio (Jun 16, 2014)

WinWiz said:


> I recently replaced 2 vintage Rockford amps with 2 pioneer 8604 amps. The new pioneer amps seem very sensitive to elctronic noise from my mobile phone. If I don't enable flight mode my speakers plays weird unpleasant sounds whenever my phone's connection changes from one mast to another.
> Am I the only one noticing this?


Win,

Amplifiers only amplify what they are given for an input signal, whether it is noise or music, the amplifier cannot tell the difference. If the amplifier is being fed a weak signal and the gain on the amplifier is turned up to compensate for that than the amplifier will have a higher noise floor and amplify any small interference or background noise that otherwise might not be noticed. Best thing is to have the signal set as a strong signal and the gain on the amplifier set lower to meet the demand of the speaker in relation to the other speaker it is crossed with. This will be especially noticeable on drivers like the tweeter. I see the industry plagued with misinformed people who are setting amplifier gains for speakers in active systems such as for tweeters to max power before distortion sets in with a DD1 or O-scope and then have to turn down the gain within the DSP to -10 db to compensate for that massive gain in power. All that does is put your tweeter at risk of blowing up if you get a speaker pop (without cap), raise the noise floor of the amplified signal, and overall raise the chance of amplifying interference in the signal path. A DD1 is great for setting the gain for a subwoofer but not for amplifying the signal for tweeters or even midbass drivers. Most automotive amplifiers are designed to accept a signal from an aftermarket HU which typically puts out ~ 4 volts. The less you give it for an input, the more you have to turn up the amplifier gain to match that input, and the more low level noise it will also amplify if present in an analog signal. 

I’m not saying you are doing this but trying to make a point that setting the amplifier gains (setting up the tune) is very important for noise rejection and that it should be carefully looked at when having noise issues with a very powerful amplifier pushing a speaker that may only need 5 watts to keep up with a 1000 watt subwoofer. It could also be a whole host of other things like ground loops, a bad amplifier itself (it is a budget amp) or crappy input cables or loose connection.


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## Lanson (Jan 9, 2007)

WinWiz said:


> I recently replaced 2 vintage Rockford amps with 2 pioneer 8604 amps. The new pioneer amps seem very sensitive to elctronic noise from my mobile phone. If I don't enable flight mode my speakers plays weird unpleasant sounds whenever my phone's connection changes from one mast to another.
> Am I the only one noticing this?



The Pioneers are Full-range Class D with a high frequency switch rate, so they could very well be picking up the same noises you can get when you put a phone near some early-release bluetooth headsets, like some of the older ones used in call centers.



Distance from the phone seems to be the solution for those headsets, not sure how you're going to get around that in a car though.


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## WinWiz (Sep 25, 2013)

Guess I could wrap my amps in tin foil, but that might cause some cooling issues...


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## rton20s (Feb 14, 2011)

There have also been quite a few reports of that generation of Pioneer GM-Ds having noise issues. I'm not sure how common it is. It seems the amps either work great, or they don't. I don't recall seeing anyone who had a noise issue successfully trouble shoot and eliminate the problem.


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## WinWiz (Sep 25, 2013)

Sorry for highjacking this thread...
I also have noise from my midwoofers (powered by one of my Pio 8604) It sounds kind of like faint pink noise. I generally only hear it when playback is paused and my engine is off. It started when I installed my Dayton dsp so I think the dsp is causing it. It irritates me, so tried new rca cables, rerouting the cables and grounding dsp and headunit, relocating the dsp -but it didn't help ?
The Dayton dsp is known to cause noise when the bass remote is connected, but I don't have the remote. Maybe I should check if the pio amp powering my midwoofers is the one making the mobile phone noises...


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## JCsAudio (Jun 16, 2014)

tyroneshoes said:


> Nice interesting post. Im doing something very similar and Ive been through about 25 amps or so comparisons, except for using the on axis bookshelves full range, I also try each amp on a sub.
> 
> I will say that I also grabbed the Zapco Studio 2x SQ from world wide for $65 as well. I was also somewhat underwhelmed by this amp as well. The amp I was comparing to a/b was a zapco studio 100 from 93 so it was very similar power. It was fine, but no where as clear and detailed as the older zapco, or the new full range class d amps from zapco. It was very easy to swap my into my car playing tweeters from 2.5 up and it was not as nice as the old zapco studio 100 so I am not using it and put the old studio back in.
> 
> ...


tyroneshoes,

I’m sorry I did read your post and then completely forgot to reply. :huh2: Thank you for sharing your commentary and it’s interesting to read about your findings on those Zapco and Kenwood amplifiers. I remember I had a real cheap 2 channel Kenwood back in the day and swapped it for that Alpine 3548 I used in my tests and was struck by the improvement in sound running a two way front stage. I then tried the same test but this time bridged driving a JL Audio microsub and the Alpine was noticeably more powerful sounding. I guess Kenwood has come a long way since those days.

I kind of want to do this again but this time get some DIYMA members involved and post their commentary. That might be interesting and of course it would have to be a blind test.


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## SlvrDragon50 (Apr 10, 2017)

WinWiz said:


> Sorry for highjacking this thread...
> I also have noise from my midwoofers (powered by one of my Pio 8604) It sounds kind of like faint pink noise. I generally only hear it when playback is paused and my engine is off. It started when I installed my Dayton dsp so I think the dsp is causing it. It irritates me, so tried new rca cables, rerouting the cables and grounding dsp and headunit, relocating the dsp -but it didn't help ?
> The Dayton dsp is known to cause noise when the bass remote is connected, but I don't have the remote. Maybe I should check if the pio amp powering my midwoofers is the one making the mobile phone noises...


Are you talking about the bluetooth noise floor? Does that pink noise remain when you aren't connected via bluetooth?


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## tyroneshoes (Mar 21, 2006)

JCsAudio said:


> tyroneshoes,
> 
> I’m sorry I did read your post and then completely forgot to reply. :huh2: Thank you for sharing your commentary and it’s interesting to read about your findings on those Zapco and Kenwood amplifiers. I remember I had a real cheap 2 channel Kenwood back in the day and swapped it for that Alpine 3548 I used in my tests and was struck by the improvement in sound running a two way front stage. I then tried the same test but this time bridged driving a JL Audio microsub and the Alpine was noticeably more powerful sounding. I guess Kenwood has come a long way since those days.
> 
> I kind of want to do this again but this time get some DIYMA members involved and post their commentary. That might be interesting and of course it would have to be a blind test.


Yes, the current excelon full range class d amps are a far reach from the inexpensive kenwoods with the "1000" watts on it. Kenwood made in japan amps were amazing, then they fell off with the PS line. I swapped alpine pdx gen1 amps for the kenwood kac-x4r and x1r and it was like my a/b amps were back but with built in dsp. That x4r I will never sell. Still works perfect 10 years later. 

Since then, Kenwood seems to be some of the best sounding class d's, on par with my zapco st-204d sq, Matts digital fr, Focal/Zed class ds, malaysian and Indonesian high end amps. and they managed to lessen the size and efficiency while using Nichon caps in some. And these amps are super under rated. The 5 channel kenwood prior to the "high res" snake oil was rated at 50x4 and 300x1 and give a constant 100x4 and 500x1. They also have an interesting dual sigma negative feedback circuit that seems to just make everything sound better. And you can get these amps for under $250. Well worth the extra 30 or so or less than the pioneer. The design shows lots of thought and fantastic build quality. Like you would expect from an Italian manufacturer or a very high end esoteric name. 

I suggest giving an excelon a try from the past 5 years. You will be impressed. The xr801-5 and the xr901-5 are fantastic 5 channel amps. Unfortunately, they did not add a bass knob untill recently but I always just use an inline rca potentiator. And the Marine version of xr801-5 is going for 225 new. Id take them over the pioneers any day. Theres a big d wiz comparing the kenwood and pioneers on the dyno. Its the full range channels that are actually more powerful than the pioneers on the kenwood and what make them superior, to me. The 4 channels are fantastic too but the 5 channels are some of the best high end class d 5 channels and incorporated the exact same 4 channels with a mono in same 11" chassis. 

Two of these kenwood 5 channels can be bridged to a 3 channel for mid bass/midwoofers and a sub, and the second 5 channel can power tweeters /midrange or rear fill and a second sub, if needed (100x4+300x2+500x2) That is the best deal out now if you ask me. Plus they look slick.


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## tyroneshoes (Mar 21, 2006)

jimmyjames16 said:


> Hey Tyrone.. I have to agree with you with the Kenwood Excelon class D's .. they sound incredible and if not better than the JL HD or Arc XDi amps I had prior.
> 
> I actually took your advice on these a few years back and didn't expect them to sound so good because they were first off a "Kenwood" .. and their lower price mark just seemed like another low grade amp that would either blow or sound crappy overall . That wasn't the case at all. The XR400-4 sounded a bit sharper and stronger than it's predecessor - the XR-4S .. it was a bit more cleaner and ballz-ier.
> 
> ...


Glad to hear. Also dont like JL HD or the pdxs (PDR>PDX) and have had issues with arc since the class g/h and xdi (first gen). I think the jl xds are better personally but no better the excelons. I am a big fan of the JL slash amps however. Didnt try the rd yet.

The zapco st204d sq is a very nice amp, but I bypassed my typical listening process and put it right in my car. It sounds great but since I assess using full range bookshelves with tweeters, I couldnt give a fair assessment in my listening room/office. I do know they have TONS of clean power and power my 7" woofers and 10" without breaking a sweat with minimal gain, so I recommend them. 

However, I bought it from WWS for 250 new as they listed it as a 2 channel. Now its $500. So you can get 100x8 + 500x2 using the excelons for the same price. So, I dont know if Id say its worth 500, but I dont think any car amp is unless your compete and have sponsors or it has built in dsp. 

I did not try the other zapco micro digital line, this amp is 13" long but 1200 watts rms. Low ESR caps, and hardly any difference on my mids from my old studio 300x. Overall, 105 amps of fusing and 90% efficiency and audio caps..Its the most powerful reasonably sized zapco 4 channel ever and I have no complaints. Its mounted under seats so the only issue with the kenwoods in same location under seats was fan noise. No fan on the zapco. Great build quality and heavy. I put a gut pic of it in the hot deals WWS post.

I def recommend them. The only one I would swap for is the Focal Zed made 5 channel as I am very impressed by them too, love the cosmetics and pwer rating is perfect for my setup and see them going for under 300 on ebay at times. However, zeds have some reliability issues and both my previous zapcos were purchased by me and used for 25 years and my zapco studio 100 is still powering my tweeters. So I just have a brand preference for zapco. Im even using zapco/esb speakers.


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## Patriot83 (May 10, 2017)

tyroneshoes said:


> Glad to hear. Also dont like JL HD or the pdxs (PDR>PDX) and have had issues with arc since the class g/h and xdi (first gen). I think the jl xds are better personally but no better the excelons. I am a big fan of the JL slash amps however. Didnt try the rd yet.
> 
> The zapco st204d sq is a very nice amp, but I bypassed my typical listening process and put it right in my car. It sounds great but since I assess using full range bookshelves with tweeters, I couldnt give a fair assessment in my listening room/office. I do know they have TONS of clean power and power my 7" woofers and 10" without breaking a sweat with minimal gain, so I recommend them.
> 
> ...


Which sub/amp combo do you like better; your Subaru or jeep setup?


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## tyroneshoes (Mar 21, 2006)

As far as sub, the jeep by far. The Boston g5 10" is in a vented enclosure getting 600+watts while the sundown sd3 10 sealed in .7 cuft getting the 550 from the zapco. The boston is also more efficient. Id be running the g5 10 if it would fit in the slim enclosure I have, but a SI BMV III 12 just showed up today that I plan to install in the sd3 10"s location as it will fit and Im all for more cone area.

I took a long drive today and while the SD3 10 is a fine sub, one 10 doesnt have the output I like (not far off though) and has a hard time keeping up with my front stage when louder. It just seems to plateau due to the underhung design but is a good sounding sub. If I had 2 of them, or even a 12" no problem. But the boston g5 is one of my favorite all time car subs and in 1.3cuft @32hz sounds amazing.

I didnt try to hook up the vented g5 to the zapco but Im sure the difference between the PDR mono and bridged zapco amps would be very small. It really needs no more that 450-500 watts.

So Im replacing the sd3 10. first going to try the SI 12" that showed up today and I also have a BNIB Nakamichi 12 about 25 years old that is an amazing sounding sub as well that fits in the same enclosure as well. Just half the excursion of the SI, and 300 watts rms but buttery smooth subs those Naks. Also have an Alumapro RX SQ 12". So moving to a single 12. Off the zapco. All the above fit the enclosure and amp power 

The Jeep is more of a work car that I swap stuff I have and try new things in. Has more room and Im less picky about perfection. Subaru is my SQ focused car.

If nothing provides the output I seek in the subaru, Ill just do some glassing and put the g5 and matching pr @ 30hz in the .5 they require and I would have more than I need. But effort


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## JCsAudio (Jun 16, 2014)

Thanks tyroneshoes, I will keep my eyes pealed for any of those Excelons, although I don't really need anymore amplifiers. In fact I think I need to sell some of these off as I have too many. As for monoblock amplifiers, the most impressive I have experienced so far would be a Rockford Fosgate Power 1500 class BD. I swapped that with an Infinity K1000 and noticed a difference right away with an SA12 subwoofer. It was probably attributable to the constant power design or maybe just more power overall but it impressed me. I wish you were closer as I'd love to hear some of those amps you have. 

Thanks


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## WinWiz (Sep 25, 2013)

SlvrDragon50 said:


> Are you talking about the bluetooth noise floor? Does that pink noise remain when you aren't connected via bluetooth?


I don't have the BT stick.


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## JCsAudio (Jun 16, 2014)

Update: the Pioneer D8604 seems to have an issue with channels 1 & 2. My tweeter levels were all over the place, sometimes cutting in and out and I thought it was a loose connection. I changed the RCA and all was good for a while but today after a long tuning session the tweeters started doing this again. Just before they were noticeably losing power (by ear) I was having trouble level matching them to the door woofers. First they were good, then they were too low, then I readjusted them and they were too high again. Seems to be related to how hot the amplifier was getting and the hotter it got, the worse it got. Measured 112 degrees on the amplifier with 95 degrees in the truck (hot day). I swapped it out for the DLS for now and finished the tuning and the tweeters are holding their levels now. 

So we’ll see what happens as it could be the DSP but I think not. If the problem doesn’t come back than I’m going to blame the D8604 for what I call, you get what you pay for qaulity. Great sounding amplifier but the the qaulity of the components inside seem suspect to me. Could also just be a random case where I got unlucky. I’ll give it a few weeks and see what happens.


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## EricP72 (Mar 23, 2008)

I wish I never sold my Kenwood x4r. So I have a question, do you guys believe the Kenwood excelon amps are better than the new pioneer gm-dx975 5 channel?
And I have a pioneer gm-x924 class A that I. Curious as to how it would stack up against the other amps you tested.


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## JCsAudio (Jun 16, 2014)

Funny, my brain must be playing tricks on me because I like the way my GB10 tweeters sounded with the Pioneer over the DLS. Just went through some songs on my 1 hour commute to work to come up with this opinion. Will have to play with the tune some more to make sure it’s not that.


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## soundstreamer (Jun 2, 2015)

I have the Kenwood XR900-5 and I really like it as well. I have it on my midranges, tweeters, and sub and it provides plenty of power and to my ears sounds very good. I had my mids and tweeters on a Alpine PDX F4 and I cant say I noticed hardly any difference in the sound. The only complaint I have with this model is the horrible screw heads for the speaker and power terminals. It is very easy to strip the heads so you have to be extremely careful with them. I had to send my first one back to Crutchfield because of this problem.


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## tyroneshoes (Mar 21, 2006)

manish said:


> I wish I never sold my Kenwood x4r. So I have a question, do you guys believe the Kenwood excelon amps are better than the new pioneer gm-dx975 5 channel?
> And I have a pioneer gm-x924 class A that I. Curious as to how it would stack up against the other amps you tested.


Yes I prefer the Excelon to the pioneers. I know theres a limited pioneer version with updated caps but its $150 more and I have not heard it. Kenwood still uses Nichion.

That Pioneer gm-x924 is a class a/b but with class a bias...Great amp.


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## drop1 (Jul 26, 2015)

I've been arguing that Amps sound different for forever now. Most budget amps have an edginess that I find cant be tuned out. I mean yes you can tune it out but it will cost you clarity to do so. 
I really loved my old Focal amps. They had a lush smooth sound and could be tuned bright without ever being harsh or brittle. I lost those to a flood and wound up with jl hd's. The hd's arent bad amps but they cannot deliver that ultra smooth top end I like . I've never owned anything of a higher tier than these 2 amps and that makes me curious just how good can amps get ? I liked the jl slash amps but had super limited dsp at the time. A p80 head unit with left and right 15 band was. I hated the Xd amps even with full dsp.


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## tyroneshoes (Mar 21, 2006)

Yeah. I used to think it was all psycho-acoustics until I had the chance to a/b them indoors with high end speakers so its the exact environment and drivers on axis and no ambient noise. The tweeters on my ref speakers are vifa xt rings so they extend far past my audible range. Its very clear amps sound different, but the difference may not be significant for most to acknowledge or value.

there is a point of diminishing returns but if I can fit it, Im always going to prefer a/b on my full range speakers. Even the current Sony GS 4 channel is a small class a/b that sounds excellent. The Audio Designs ADS60.4 I have is very impressive. 

Class D can sound as good as A/B,but not better than a well designed a/b amp...On this site the mosconi zeros are a good example of an a/b amp that will sound better than 90% of any amplifiers and all class d amps. But for me, old school zapcos. The zapco set below were my all time fav amps. Like someone else said...Oz Audio and zapco were magical together as was the focal Utopia and zapco studio 300x and 150s or the Z/Comp Zaps amp seen below .I went to an old school Directed pre sellout 5 channel to have an all in one chassis amp and the focals became brittle. Back in the zapcos. Story of my Car audio history. Aways chasing the Oz Audio/Zapco VW Scirroco system I had in the 90s.

I have a Malaysian Clarion/Addzest Pro Audio amp on the way to test.

Some pics of it. Also a/b with class a bias.


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## EricP72 (Mar 23, 2008)

Ok I have a question, I recognize that Kenwood amps seems to have more cone control over woofers. I attribute that to damping factor and the sigma drive circuit. So my question is...what Kenwood amp or any amp is tour preferred amp of choice for powering a sub in a sq setup. Sub would be in a sealed enclosure. Basically past or present amp. I'm curious to what you guys think esp with Kenwood amps


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## JCsAudio (Jun 16, 2014)

Manish, there is no proof that certain Kenwood amplifiers have better cone control over others. Everything in this thread including most of my information has mostly been subjective and anecdotal information. All we know is that not all amplifiers sound the same but we have no good data to back this up and show why that is. Furthermore the debate about damping factor has been beaten to death and if you really did through all the misinformation you should find that damping factor isn’t really a factor with today’s amplifiers when you look at everything else that affects the speaker’s cone control such as the actual mechanical suspension of the speaker itself. 

Also, in my testing with the amplifiers in this price range I could not see class A/B having any advantage over Class D amplifiers. There is no measurable hard evidence that shows any of the class A/B amplifiers doing anything better than the class D amplifiers. It’s all anecdotal information here so it’s not worth much other than we know not all amplifiers sound the same. I have to tell myself this all the time because my brain wants to believe all the anecdotal information on the internet is all true.


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## EricP72 (Mar 23, 2008)

Yeah I have read the same post here as well. But my in a few amps there seems to be a difference. I know I can definitely tell a difference between my Kenwood kac-1023 vs pretty much any other amp I have run including my old pg ms2.125 amps. Now between most class D amps, I agree ?. But there is something to be said for a amp with a stout power supply. I guess I was too wordy but I was basically looking for what they felt was the best performing mono amp that didn't lose steam with extended low note passages.


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## JCsAudio (Jun 16, 2014)

manish said:


> Yeah I have read the same post here as well. But my in a few amps there seems to be a difference. I know I can definitely tell a difference between my Kenwood kac-1023 vs pretty much any other amp I have run including my old pg ms2.125 amps. Now between most class D amps, I agree ?. But there is something to be said for a amp with a stout power supply. I guess I was too wordy but I was basically looking for what they felt was the best performing mono amp that didn't lose steam with extended low note passages.


Didn't realize you were talking monoblocks so in that case I 100% agree that a stout power supply definitely makes a difference. I can tell a difference too with my Rockford Fosgate Power bd1500 vs cheaper conventional amps.


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## tyroneshoes (Mar 21, 2006)

I agree with both the above posts. Except, I am pretty convinced that certain class ab amps will sound better on full range.

Now the Kenwood KAC-x1r Im selling is a very nice sounding mono amp that has dual power supplies. As far as the control aspect, kenwood has a dual sigma negative feedback circuit that seems to help, but not a major difference. And most quality amps do have a neg feedback circuit built in. The japanese OS Kenwood kac-1023 you have is just a fantastic amp overall. And Id be using it if you could. 

In your sig, I see you have a Pioneer PRS-X720. Thats a fantastic amp. is that currently powering your subs? If so, I dont think youll get much of an improvement from swapping that, unless the current draw is too much.

Like JCSAudio I also am very fond of RF amplifiers on subs and I would run one of them if I was was given the option between the punch or power RF vs current kenwood excelon amps. I have never had an issue with the kenwood amps, but RF just makes very solid sub amps and they are tanks. So both of the subjective listeners agree there. 

The current kenwoods excelons are solid, but not like the old Japanese versions. Those are some of my all time favorite amps


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## EricP72 (Mar 23, 2008)

So currently, I have a prs720, mtx2300x, Kenwood 1023, and a pair of pioneer gm-x922 amps. I have the amps and speakers listed in my signature but nothing Installed. As a matter of fact I sold one of the 15" subs. I haven't decided on which sub to run as I have a pair of pioneer ts-w12prs, infinity kappa 120.90, and that 1 rf T1 15". But I'm waiting on the new SI SQL-15 to drop unless I come across a JBL W15GTI. So yeah the 1023 is a option and so is the prs amp. Just unclear what I want to run for subs. And the RF 1500 is now on my radar if you guys think that is a superior amp to the ones I have already


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## tRidiot (Jun 29, 2006)

So if it's so obvious, how come no one ever claimed Richard Clark's $10k prize? Wasn't he the one who laid out the challenge to try to identify differences? Or was it cables and not amps? Been a few years... I might be misremembering.


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## ajt976 (Feb 27, 2019)

tRidiot said:


> So if it's so obvious, how come no one ever claimed Richard Clark's $10k prize? Wasn't he the one who laid out the challenge to try to identify differences? Or was it cables and not amps? Been a few years... I might be misremembering.


Funny because I just listened to the podcast with him on there yesterday, super interesting. It WAS amps by the way.


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## JH1973 (Apr 21, 2017)

At the Bloomington SQ event last September Benny Z had everybody in suspense and never came through with the answer.

He said Richard Clarke has an ongoing proposition where if the listener can tell or guess which amplifier is playing he'll give that person $10,000 cash.

This intrigued me and I pushed Ben to tell us more but he told us we'd need to listen to the upcoming SQology podcast for further explanation.........well he never brought it up on the podcasts since that I know of......


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## ajt976 (Feb 27, 2019)

JH1973 said:


> At the Bloomington SQ event last September Benny Z had everybody in suspense and never came through with the answer.
> 
> He said Richard Clarke has an ongoing proposition where if the listener can tell or guess which amplifier is playing he'll give that person $10,000 cash.
> 
> This intrigued me and I pushed Ben to tell us more but he told us we'd need to listen to the upcoming SQology podcast for further explanation.........well he never brought it up on the podcasts since that I know of......


Here you go:
SQOLOGY Car Audio Podcast
feat. Richard Clark - Autosound 2000


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## JH1973 (Apr 21, 2017)

ajt976 said:


> JH1973 said:
> 
> 
> > At the Bloomington SQ event last September Benny Z had everybody in suspense and never came through with the answer.
> ...


Awesome,thank you!!


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## tyroneshoes (Mar 21, 2006)

Get yourself a power supply and listen to it indoors and decide for yourself. 

I used to be like oh Richard Clark challenge as well, but then I actually sat indoors and listened to various amps.

Just like when building passive crossovers, all the components the sound travels through does create a sonic signature. And changing caps and coils does alter the sound even if same values. Same goes with amps

Nice link on the topic (though focused on home audio)

https://forum.audiogon.com/discussi...plifier-challenge-why-couldn-t-anyone-pass-th

https://benchmarkmedia.com/blogs/application_notes/power-amplifiers-the-importance-of-the-first-watt

A high end amplifier designer chimes in "This explains why my amps are designed as Class A to 2/3 power. The switching distortion at high output is insignificant compared to everything else. However at very low levels switching distortion is audible (at least on test signals) - so it is preferable to be in Class A at low levels (of less than 1/10 of a watt)

The article confirms to me that only carefully designed listening tests at very low levels will lead to audible differences between well designed high quality power amplifiers. Alternatively, stressful loads or extreme power requirements would audibly differentiate the amplifier with better performance."


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## tyroneshoes (Mar 21, 2006)

manish said:


> So currently, I have a prs720, mtx2300x, Kenwood 1023, and a pair of pioneer gm-x922 amps. I have the amps and speakers listed in my signature but nothing Installed. As a matter of fact I sold one of the 15" subs. I haven't decided on which sub to run as I have a pair of pioneer ts-w12prs, infinity kappa 120.90, and that 1 rf T1 15". But I'm waiting on the new SI SQL-15 to drop unless I come across a JBL W15GTI. So yeah the 1023 is a option and so is the prs amp. Just unclear what I want to run for subs. And the RF 1500 is now on my radar if you guys think that is a superior amp to the ones I have already


I think the amps you have in your collection are excellent as is and the only benefit you would get from swapping is efficiency and a smaller size. As far as sound, youre fine as is. I also liked those Bright yellow PRS 12s. Accurate sub. We have similar taste.

Heres a 15" gti

https://www.ebay.com/itm/NEW-IN-THE...988562&hash=item3fc79c99e2:g:U8UAAOSwe8ldLmO6


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## JCsAudio (Jun 16, 2014)

I’ve been doing some research while I sit in a car for hours and hours traveling to Florida and listened to Richard Clark’s interview on the SQOLOGY podcast. This has me seriously thinking why I was able to hear differences between amplifiers. If Richard Clark is right than what we’re the differences I was hearing. Was it just level differences of less than 1 db or was it something else? Might have to perfect and revisit this test later on.


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## drop1 (Jul 26, 2015)

JCsAudio said:


> I’ve been doing some research while I sit in a car for hours and hours traveling to Florida and listened to Richard Clark’s interview on the SQOLOGY podcast. This has me seriously thinking why I was able to hear differences between amplifiers. If Richard Clark is right than what we’re the differences I was hearing. Was it just level differences of less than 1 db or was it something else? Might have to perfect and revisit this test later on.


The differences I've heard have little to do with frequncy response and more to do with texture and and dynamics.

I always found this a really interesting subjust as lots of audio enthusiasts say they all sound the same and musicians like me, who happens to be a bassist, search out amplification with certain qualities to play our instruments through Ask any real musician if amps sound the same and they will look at you like you are stupid lol. On that side of the industry amps are intentionally made to sound different. On this side they are made to sound as neutral as possible.
Some Amps sound really open and dynamic where others may sound more closed and compressed. 

Something ive noticed is that these subtitles are better noted over time. Tine to intimently get to know the amps. Subtle characteristics that may not be readily heard in a short demo or comparison. 
I know jack about the inner workings of amplification but I know what I hear. That's all I need to know.


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## JCsAudio (Jun 16, 2014)

I know I hear a difference but I don’t know why and that is what I want to know. Is If phase differences or something else. Wish I had the tools to measure it.


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## cmusic (Nov 16, 2006)

JCsAudio said:


> I’ve been doing some research while I sit in a car for hours and hours traveling to Florida and listened to Richard Clark’s interview on the SQOLOGY podcast. This has me seriously thinking why I was able to hear differences between amplifiers. If Richard Clark is right than what we’re the differences I was hearing. Was it just level differences of less than 1 db or was it something else? Might have to perfect and revisit this test later on.


RC has a history of taking true and solid information and saying it in a way that makes it seem controversial but if you slow down and realize what he is saying (and not saying) it makes perfect sense. RC said "no one can hear the differences between amps in my test." Everyone took it as he meant "all amps sound equal".

RC's test is a simple scientific test where all variables are eliminated except for the one being tested for. In RC's case what is being tested is _"can the listener *HEAR* the differences in amplifiers?"_. This means his test is testing the listener's hearing, NOT the amplifiers. In accordance to the scientific testing method, all variables in the amplifiers must be eliminated for the test to be valid. This is why RC must test each amp used before the test, and then use eq or other adjustments to eliminate any differences between the amps that might allow one to hear differences. 

Then RC requires the people taking the test to go through several (I've heard between 10-20 tests) qualifying rounds of listening before they must get 10 out of 10 tests correct to to win his $10,000. By this time most listeners will have listening fatigue and will not be able to hear critically as well as they did at the beginning of the test. 

I know of one person that did beat the test. RC then demanded he re-test each amp and found one amp to be less than 1 dB louder than the other one. He then voided that test, claiming the amps were not adjusted to produce the same exact output. 

RC used this test to give him great notoriety in the car audio world in the late '80s through the early '00s. RC is 100% correct in that in his test, with its extremely strict parameters, one cannot hear a difference between amplifiers. However amplifiers are not used in the manner used in the test in the real world. 

It's like saying a since both a Toyota Prius can drive on a road at 55 MPH and a Ferrari 812 Superfast can also drive on the same road at 55 MPH, then both cars are equal. They are equal if the only thing you are testing for is if the cars can do 55 MPH on the same road. In real life they are no where near equal.


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## drop1 (Jul 26, 2015)

cmusic said:


> JCsAudio said:
> 
> 
> > I’ve been doing some research while I sit in a car for hours and hours traveling to Florida and listened to Richard Clark’s interview on the SQOLOGY podcast. This has me seriously thinking why I was able to hear differences between amplifiers. If Richard Clark is right than what we’re the differences I was hearing. Was it just level differences of less than 1 db or was it something else? Might have to perfect and revisit this test later on.
> ...


Beautiful.


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## ckirocz28 (Nov 29, 2017)

drop1 said:


> ..... search out amplification with certain qualities to play our instruments through Ask any real musician if amps sound the same and they will look at you like you are stupid lol......


Seems a bit like comparing apples to oranges, in the musician world "amplifiers" usually come with a speaker and some sort of effects (distortion) built in. Rack mount amplifiers are usually chosen to reproduce a signal faithfully, same as car audio amps.
While I agree that car audio amplifiers can sound different from one another, I think that most are so close that only someone with a "golden ear" would hear the difference.


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## drop1 (Jul 26, 2015)

ckirocz28 said:


> drop1 said:
> 
> 
> > ..... search out amplification with certain qualities to play our instruments through Ask any real musician if amps sound the same and they will look at you like you are stupid lol......
> ...


I wasnt really trying to make a direct comparison. I even stated that playback amplification tries to remain as neutral as possible .


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## JCsAudio (Jun 16, 2014)

JCsAudio said:


> Update: the Pioneer D8604 seems to have an issue with channels 1 & 2. My tweeter levels were all over the place, sometimes cutting in and out and I thought it was a loose connection. I changed the RCA and all was good for a while but today after a long tuning session the tweeters started doing this again. Just before they were noticeably losing power (by ear) I was having trouble level matching them to the door woofers. First they were good, then they were too low, then I readjusted them and they were too high again. Seems to be related to how hot the amplifier was getting and the hotter it got, the worse it got. Measured 112 degrees on the amplifier with 95 degrees in the truck (hot day). I swapped it out for the DLS for now and finished the tuning and the tweeters are holding their levels now.
> 
> So we’ll see what happens as it could be the DSP but I think not. If the problem doesn’t come back than I’m going to blame the D8604 for what I call, you get what you pay for qaulity. Great sounding amplifier but the the qaulity of the components inside seem suspect to me. Could also just be a random case where I got unlucky. I’ll give it a few weeks and see what happens.


Update: I was still having an issue with the tweeters fading in and out and the levels going up and down even with the DLS amplifier running the show. I tapped on the tweeters and they came alive again so I removed the A pillars and I think the AudioFrog sets screws for the GB10 tweeters needed a little more tightening. Needless to say I’m not a fan of those set screw wire connections right now. Looks like the Pioneer D8604 is actually not faulty at all as I originally assumed.


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## tyroneshoes (Mar 21, 2006)

Im listening on speakers with passive crossovers professionally designed and phase corrected so theres no variability. Im now using the current Zapco studio a/b SQ series and I have to say, Its impressive and I think I didnt give them enough credit. The zapco class d in my car have more power and sound a little better louder (3x the power) but I think the two or 4 channel a/b studio sq are nice but Id suggest bridging them if in a car on anything but tweeters or small mids. I tried a stetson mini amp and that had noisefloor that was clearly audible at min gain.

These speakers are my testers and the JL cp108 sub


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## EricP72 (Mar 23, 2008)

tyroneshoes said:


> I think the amps you have in your collection are excellent as is and the only benefit you would get from swapping is efficiency and a smaller size. As far as sound, youre fine as is. I also liked those Bright yellow PRS 12s. Accurate sub. We have similar taste.
> 
> Heres a 15" gti
> 
> https://www.ebay.com/itm/NEW-IN-THE...988562&hash=item3fc79c99e2:g:U8UAAOSwe8ldLmO6


So question for you, between the two Kennwod Exceleon amps, which series do you considered superior? XR900-5 vs x801-5? I'm asking because since I'm thinking of trying out stealth set up and using 3 five channels ( i have 3 4dvc subs and rear fill). I'm curious to which model you prefer.


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## JCsAudio (Jun 16, 2014)

Ok this time around I have the above mentioned Kenwood XR 400-4 to put up against the still on top DLS cci44. This is Kenwood‘s attempt at an amplifier marketed as a SQ oriented class D amplifier with audiophile grade components. It’s also a very small but good looking amplifier. I got my wife and daughter to be the judges but my son wants no part of this anymore so he is out I guess. I also asked them each the same question after they gave me their comments like before and that question was: Do you think #1 sounds better, #2 sounds better, or do you think it is a tie? I also switched up which one they started with first so #1 could be either one and they would have no clue. 

Amplifier #1 was the DLS CCi-44.
Amplifier #2 was the Kenwood XR 400-4 Class D

Wife
#1 (DLS) Vocals louder and stood out more from the background music. Nuances of sound blended well. 

#2 (Kenwood) I could hear every separate part, was very crisp and clean. Vocals didn’t seem to stand out as much compared to #1. 

Answer to question: Both sounded very good and very similar. I say it’s a tie. 

Amplifier #1 was the Kenwood XR 400-4 Class D this time
Amplifier #2 was the DLC CCi-44.

Daughter
#1 (Kenwood) background music more pronounced. Bass didn’t have as much reverberation or echo. Bass sound stopped more abruptly, bass was more concise. More echo/reverberation in voices.

#2 (DLS) background music not as loud. Bass less concise (bass not as much of a complete stop) better balance of sound.

Question: These were easier to tell apart. Both sound very good but I liked the balance of #2 better. 

So I think these are very close. I copied their notes basically word for word even though they may not make as much sense this time. I think I will run this test again later on. I have a Masconi amplifier and a Kicker amplifier that I will be putting to the test next so stay tuned.


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## DavidRam (Nov 2, 2014)

JCsAudio said:


> I have a Mosconi amplifier and a Kicker amplifier that I will be putting to the test next so stay tuned.


I look forward to the tiny amp test! With it's price tag, that Pico 2 better do well...


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## JCsAudio (Jun 16, 2014)

I think it will David. I’ve been using it in my truck and already think it sounds great although it does have a higher noise floor than my DLS has.


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## JCsAudio (Jun 16, 2014)

Well, You guys will have to go to that other site to find out the results. I ran three separate amplifier tests. 





__





My own Amplifier Sound Quality Shootout - Page 2


Posting this from another forum where I started this for any CAJ members who might benefit. This has been posted many times and debated to death here. Is there a sound quality difference between amplifiers given that they are of good quality and at a reasonable price point? I was of the camp...



www.caraudiojunkies.com


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## DavidRam (Nov 2, 2014)

JCsAudio said:


> I think it will David. I’ve been using it in my truck and already think it sounds great although it does have a higher noise floor than my DLS has.


I hope you get your hands on some Mmats soon... I would love to see some comparisons done with them.


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## EricP72 (Mar 23, 2008)

Interesting test. I can think of a sleeper amp, the pioneer PRS-D800. I'd like to see that go up against any of the amps you test already.


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## JCsAudio (Jun 16, 2014)

EricP72 said:


> Interesting test. I can think of a sleeper amp, the pioneer PRS-D800. I'd like to see that go up against any of the amps you test already.


I do have a Pioneer PRS D4200F that I ran in the test that did well. I guess I could run it against the DLS even though the Alpine 3548 won against the Pioneer PRS D4200F in the last test and the DLS won against the Alpine 3548 after that.


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## EricP72 (Mar 23, 2008)

I have the PRS-4200f as well, but my PRS-D800 is superior to my ears.


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## JCsAudio (Jun 16, 2014)

Superior is a strong word to use in this company and if it’s truly superior to the d4200f then you do have a sleeper amplifier there. Unfortunately I do not have access to that amplifier so unless someone was willing to lend me one then I cannot put it to the test.


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## preston (Dec 10, 2007)

I love those little Pioneers. I use them all over the place, often as 300W rms mono blocks for my woofers or as a small (and overkill) solution for rear fill. Their so tiny and elegant looking .II don't build visual systems but I've always thought an amp display rack with 5 or 6 of those little black beauties with all the wiring tucked down neat and nice and barely visible would look really cool. 

Would love to know if they compare SQ wise (I'm of the camp that good amplifiers don't sound significantly different, but I've never really sat down and done comparisons either). But I'm just paranoid enough that I keep big, old school class A/B amps on the mids and tweets.


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## compuwiz1937 (Jun 5, 2017)

Where did you get the DLS amplifier from?


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## JCsAudio (Jun 16, 2014)

Member ANS, he was a DLS distributor and owns his own shop. I think he stoppped carrying them (maybe) and I haven’t heard from him since the forum went through the change.


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## EricP72 (Mar 23, 2008)

JCsAudio said:


> Superior is a strong word to use in this company and if it’s truly superior to the d4200f then you do have a sleeper amplifier there. Unfortunately I do not have access to that amplifier so unless someone was willing to lend me one then I cannot put it to the test.


If you pay for shipping to and from I'm willing to send in one to you for a review, I won't be using it for a few months. When I had the 4200 installed it was nice, but those d800 are special. I'm going to grab a few more when I get chance, I had worked out a deal here for some but new fridge and furnace plus Xmas put a hold on that.


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## EricP72 (Mar 23, 2008)

preston said:


> I love those little Pioneers. I use them all over the place, often as 300W rms mono blocks for my woofers or as a small (and overkill) solution for rear fill. Their so tiny and elegant looking .II don't build visual systems but I've always thought an amp display rack with 5 or 6 of those little black beauties with all the wiring tucked down neat and nice and barely visible would look really cool.
> 
> Would love to know if they compare SQ wise (I'm of the camp that good amplifiers don't sound significantly different, but I've never really sat down and done comparisons either). But I'm just paranoid enough that I keep big, old school class A/B amps on the mids and tweets.


I got 3 of them, I really wanna grab 3 more and run them. Im really trying to figure out a nice design for a amp rack display. Had the idea though of using some all black ring terminals and black wires. Or brass ring terminals with silver ground and clear power wire.


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## JCsAudio (Jun 16, 2014)

That’s generous of you Eric but I just broke down my bench setup and put it away for now. I also have a hard time getting judges to perform the test and my wife is tough to get in the right mood, although she has been great about the whole thing so I can’t complain. 

What I think I’d like to do, if there were ever enough interest, is to perform this test with a bunch of DIYMA and CAJ members as the judges and have these members bring their own amplifiers for the test just for the fun of it. We usually have a great get together here in the Northeast in the early spring. If there is a quiet place where I could set up the Kef speakers and power supplies for the blind testing, then it might be fun to try out, especially if we get an assortment of low, medium, and high end amplifiers, and the judges are consistent with their picks. The testing would of course be non scientific (no data measured) but if the results of the blind testing are as consistent as they have been so far then we could have something that points to say a certain technology or personal preference that makes the testing interesting and we might learn more about amplifier sound signatures compared to amplifier cost or technology type like class A/B vs D or GH. I think anyone without this type of experience might be shocked at the results and this could bust some myths about cost or amplifier technology, even though we won’t have empirical data to back up the testing.


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## EricP72 (Mar 23, 2008)

I think that is great idea. I was privy to a very basic version of that type of amplifier comparison with a couple of Diyma member way back. There was a review I did on the then new audible Physics 3" widebands vs a tang band driver. The test was done first with a Clarion class g/h amp, and then I decided to retrieve my Hertz 4 channel amp to try on the drivers and while the tone remain the same, we all notice a definite wider sound stage, it was definitely noticeable and that's when I realized a really good class D amp can do the job, the amp just had to use a dual mono setup. So now If I run class D, I would use one amp for left channels and one for right channels.


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## JCsAudio (Jun 16, 2014)

EricP72 said:


> I think that is great idea. I was privy to a very basic version of that type of amplifier comparison with a couple of Diyma member way back. There was a review I did on the then new audible Physics 3" widebands vs a tang band driver. The test was done first with a Clarion class g/h amp, and then I decided to retrieve my Hertz 4 channel amp to try on the drivers and while the tone remain the same, we all notice a definite wider sound stage, it was definitely noticeable and that's when I realized a really good class D amp can do the job, the amp just had to use a dual mono setup. So now If I run class D, I would use one amp for left channels and one for right channels.


Interesting, so you are implying that using two separate full range mono amplifiers enables the widest possible sound stage because the channel separation is the greatest? Never thought about that being a possibility. 

Funny, I randomly met Mike in Cabela’s today who hosted the great get together on the cape one year and we talked about the idea. He said he was going to reach out to Jerry about it.


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## EricP72 (Mar 23, 2008)

Now that is cool, please if possible record the sessions so the rest of us can watch it. 

And as far as the channel separation, you can try it yourself. If you have a class A/B amp like a 4 channel or 2, listen to some well recorded music your familiar with. Sit dead center and get the image just right. Then grab your four channel class D. Listen to it, notice the difference between the imaging? The a/b amps if they are decent will have a wider stage than the class D. Now if you got 2 identical 4 channel class D amps, bridge them, them run one for left and one for right, now you should be right or even better than the class a/b amp. There are few people who I see run their class D amps this way.


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## Bchester6 (Jan 15, 2020)

This was an epic read. Thank you for the time and effort you've put in covering a somewhat "sensitive" topic.


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## ckirocz28 (Nov 29, 2017)

EricP72 said:


> ......And as far as the channel separation, you can try it yourself. If you have a class A/B amp like a 4 channel or 2, listen to some well recorded music your familiar with. Sit dead center and get the image just right. Then grab your four channel class D. Listen to it, notice the difference between the imaging? The a/b amps if they are decent will have a wider stage than the class D. Now if you got 2 identical 4 channel class D amps, bridge them, them run one for left and one for right, now you should be right or even better than the class a/b amp. There are few people who I see run their class D amps this way.


I just switched to right and left amplifiers, JL Audio XD400/4's. I had an RD400/4, because the shop didn't have a second XD, I wanted identical amps for this exact reason. Haven't noticed a difference, yet, but my install isn't done, yet.


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## EricP72 (Mar 23, 2008)

ckirocz28 said:


> I just switched to right and left amplifiers, JL Audio XD400/4's. I had an RD400/4, because the shop didn't have a second XD, I wanted identical amps for this exact reason. Haven't noticed a difference, yet, but my install isn't done, yet.


Keep us posted on your findings.


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## High Resolution Audio (Sep 12, 2014)

JCsAudio said:


> I’ve been doing some research while I sit in a car for hours and hours traveling to Florida and listened to Richard Clark’s interview on the SQOLOGY podcast. This has me seriously thinking why I was able to hear differences between amplifiers. If Richard Clark is right than what we’re the differences I was hearing. Was it just level differences of less than 1 db or was it something else? Might have to perfect and revisit this test later on.


Richard Clark's test is inaccurate and rigged because the signal of each amp is put through a "filter". An audio system is a cumulation of the sum of it's parts. Because the the filter is the same and consistent with every amp swap, the "filtered" sound is going to sound the same.


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## High Resolution Audio (Sep 12, 2014)

JCsAudio said:


> Interesting, so you are implying that using two separate full range mono amplifiers enables the widest possible sound stage because the channel separation is the greatest? Never thought about that being a possibility.
> 
> Funny, I randomly met Mike in Cabela’s today who hosted the great get together on the cape one year and we talked about the idea. He said he was going to reach out to Jerry about it.


I'm glad that you did this test, and thank you for sharing the experience with us. Your findings are interesting for sure. I just wished that you had chosen better recorded music to do the comparison.

Imagine Dragons - Believer is very poorly recorded and has a lot of distortion. It was digitally recorded and mastered. Perhaps the results of the testing favored some of the class D amplification because the Master was recorded digitally. It sounds very "Crunchy" is the word I would use to describe that recording similar to when MP3s first arrived on scene. 

Perhaps the Alpine Class AB amp didn't sound as "clear" because it was bringing out the flaws in the recording. 

It would be interesting to repeat this test using the highest quality Analog recording or at least a AAD recording that was done with the highest quality microphones and recording equipment like Steely Dan or Boz Scaggs or the like.

A more revealing and/or accurate a system in general will bring about the flaws in the recording material thus actually make something sound worse.

There are too many variables that come into play here which may alter the results. 

With regards to our spring meet up, I'll reach out to Igor and see when he would like to get together, this time it may be on the North Shore of Boston as we haven't had one there for some time, now. The first one he put together in the Lynn area had 15 vehicles turn up. I'll run this idea by him and see what he thinks.


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## JCsAudio (Jun 16, 2014)

High Resolution Audio said:


> I'm glad that you did this test, and thank you for sharing the experience with us. Your findings are interesting for sure. I just wished that you had chosen better recorded music to do the comparison.
> 
> Imagine Dragons - Believer is very poorly recorded and has a lot of distortion. It was digitally recorded and mastered. Perhaps the results of the testing favored some of the class D amplification because the Master was recorded digitally. It sounds very "Crunchy" is the word I would use to describe that recording similar to when MP3s first arrived on scene.
> 
> ...


Sounds good Jerry, I’m certainly open to using any source provided it’s the same for all amps. Keep in mind the amplifier most preferred in the testing is a mid priced class class A/B amplifier. Amplifiers should only amplify the signal and nothing else, so whatever they are fed is spit out exactly same, only stronger. If anything is lost during the conversion or added then you might get a noticeable difference in sound. Input impedance of the amplifier can also affect the midrange of the signal, but it doesnt show up on an RTA and I can’t measure phase change. All my tests prove is that not all amps sound the same but because I can’t do proper scientific measurements I can’t say why. Like you, all I can do is theorize.

Running the tests again with more amplifiers and a better source is only going to strengthen that not all amps sound the same but still won’t help us understand why without theorizing why. We might find a pattern or preference for a particular class or brand too if we have enough samples. In the end it’s all just for the fun of it and makes for interesting conversation.


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## ckirocz28 (Nov 29, 2017)

EricP72 said:


> Keep us posted on your findings.


I can't really tell a difference in having right and left amplifiers because I had to retune at the same time. My best guess would be that there is minimal improvement, but I'm gonna leave it that way anyway.


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## Sam Spade (Mar 16, 2020)

SkizeR said:


> hes probably a kid trying to figure out life while balance starting a business, expanding said business, hiring an employee who may or may not be active in this very thread and generate work for said employee, getting jobs done, and make time for a nagging girlfriend. There will have to be a full on man hunt to find free time


Lotsa people grow up when they have kids. If you dont have kids turning 30 shocked me into it.


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## Sam Spade (Mar 16, 2020)

WinWiz said:


> Maybe this is stupid but I'm thinking maybe tests done using a phone as source isn't really representative of these amps typically usage? I Know the music is lossless but the phones DAC probably isn't as high quality as a good headunit?
> I know almost nothing about the electronics used in amps but I am guessing some designs might work better with the weak signal from a phone? I believe digital amps converts the analog input to a digital signal. If the phones dacs converts from digital to analog at a certain frequency (like 44khz) this might favor amps doing the reverse conversion at the same frequency? Because I don't know what's really inside a class D amp I could be be totally wrong about this, just seems logic to me that digital conversions from 44 to 44khz might sound better than conversions from 44 to 48 khz? If so it's giving the amps operating 44khz, or other frequencies that's matches or multiplies the inputs dac frequency an unfair advantage.
> This is just a thought I got, and in no way meant as criticism of you great work ?


Class D does not mean digital. But some amps do have a/d and or d/a convertors.


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## JCsAudio (Jun 16, 2014)

Sam Spade said:


> Lotsa people grow up when they have kids. If you dont have kids turning 30 shocked me into it.


Why did you quote such an old post? Really wish you didn’t do that. I have a lotta respect for Nick and I know what I said that was stupid. Let’s move on now.


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## Sam Spade (Mar 16, 2020)

JCsAudio said:


> Why did you quote such an old post? Really wish you didn’t do that. I have a lotta respect for Nick and I know what I said that was stupid. Let’s move on now.


Sorry no ill will intended. Just a casual comment about age and growing up. I thought what you said was fine and gently funny. But in OZ we can say stuff that we think is fine but americans are horrified by. Like the C word. In return there are things that horrify us about the US.


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## SkizeR (Apr 19, 2011)

Sam Spade said:


> Lotsa people grow up when they have kids. If you dont have kids turning 30 shocked me into it.


If i don't have a vasectomy by then, euthanize me 

Sent from my SM-G975U using Tapatalk


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## Rainstar (May 22, 2017)

SkizeR said:


> If i don't have a vasectomy by then, euthanize me
> 
> Sent from my SM-G975U using Tapatalk


Three kids and no money or three money and no kids ....🤯


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## Sam Spade (Mar 16, 2020)

SkizeR said:


> If i don't have a vasectomy by then, euthanize me
> 
> Sent from my SM-G975U using Tapatalk


Kids are great. As long as yo can hand them back. Preferably fired up and full of sugar. And you say yes to all the things parents say no to.


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## dumdum (Feb 27, 2007)

I had the snip at thirty after an accidental child, that sucked ass! I have never wanted kids... I asked my doc for the snip at 21 and they refused... I’d be 40k better off now if they had of done it then!


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## Holmz (Jul 12, 2017)

SkizeR said:


> If i don't have a vasectomy by then, euthanize me


Maybe we can make it a pay per view and have Kountz lobotomise you with sharp wit?
(Sadly we can no longer even hope)


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## rxh0272 (Jul 26, 2020)

Holmz said:


> I am not sure it is worth te bother.
> 
> I put a special set of test tones used for distortion into the tubes amps and out the nice speakers.
> Then I took the Mrs old transistor unit and the bookshelf speakers, which sound a bit dry.
> ...


Hi:
This seems to relate to the discussion I created in which we have been discussing A/B vs D for a subwoofer design. "Feelings are better than truth" says a lot. But, also seem to relate to what I was saying that when I listened to multiple systems using D on mids/highs that they sound fake, computer generated kind of, flat, not dynamic and the subs move and sound lie too controlled I guess, like the sub starts and stops, not dynamic like class A/B with overlap occuring passing the zero mark by the inherent nature of the AB circuitry. The sub should, in my opinion, function and sound dynamic. The vibration from the sub created from the sub moving unaltered through compression and rarefaction. Not compression, stop, rarefaction, stop at zero, rarefaction to Xmax, compression, stop at zero, compression to Xmax. Something like that. I can hear the sub stop at zero. as for the mids/highs, I'm not completely conscious of why I dislike the sound, but it also gives me a headache, no matter what volume. D also tends to sound poor at low volume, and at high volume is just indescribable.


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## JCsAudio (Jun 16, 2014)

rxh0272 said:


> Hi:
> This seems to relate to the discussion I created in which we have been discussing A/B vs D for a subwoofer design. "Feelings are better than truth" says a lot. But, also seem to relate to what I was saying that when I listened to multiple systems using D on mids/highs that they sound fake, computer generated kind of, flat, not dynamic and the subs move and sound lie too controlled I guess, like the sub starts and stops, not dynamic like class A/B with overlap occuring passing the zero mark by the inherent nature of the AB circuitry. The sub should, in my opinion, function and sound dynamic. The vibration from the sub created from the sub moving unaltered through compression and rarefaction. Not compression, stop, rarefaction, stop at zero, rarefaction to Xmax, compression, stop at zero, compression to Xmax. Something like that. I can hear the sub stop at zero. as for the mids/highs, I'm not completely conscious of why I dislike the sound, but it also gives me a headache, no matter what volume. D also tends to sound poor at low volume, and at high volume is just indescribable.


With all due respect, please start another thread on this topic so this one doesn’t get cluttered with the old Class A/B vs D debate. There are literally hundreds of threads here on the class A/B vs D debate. There is also the Richard clark tests and Andy Wehmeyer commentary as well. If you look back into the tests in this thread, you will see that both a class D and class A/B amplifier were the two best sounding amplifiers (subjectively) in the blind A vs B testing. Monoblock type bass amplifiers were not tested here though. With class D though there is more variation in good vs bad designs because that design is more difficult to implement well because it is more complex. If done right though it can sound just as good as class A/B and that has been proven time and time again. There are of course bad class A/B designs as well.

Currently I’m running some more tests. More to come.


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## JCsAudio (Jun 16, 2014)

Small update:

I was able to make a device that allows me to switch amplifiers with the press of a button without even interrupting the music so I can switch amplifier A with amplifier B at my will as many times as I want while playing through my Kef speakers and directly compare the amplifiers to each other without knowing which one is actually playing and without stopping the music. I used a few high qaulity high amperage relays, an on/off push button switch that I hold in my hand, and a lot of wiring. 

I just did the test on myself with the two Alpines I have to try it out. The Chinese made Alpine MRP F240 vs the old school Alpine 3648. After some listening tests at first I could not tell a difference but then I noticed I liked the midrange a little bit better with the 3548. I didn’t know which one was playing because the equipment is housed behind wood boards and there are no visual cues. I had to keep track of the button presses but when I looked behind the board it was the 3548 that I preferred. This device is awesome and is a game changer with my amplifier shootout now. 

I will be putting a JL Audio Vxi800/8i to the test. 

Hmm, I could bring this device to the next meet. That would be fun to watch you guys put your amplifiers to the test. Some may have some hurt feelings though when they find out their expensive amplifier loses to something considered less great, lol. 

More to come!


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## seafish (Aug 1, 2012)

JCsAudio said:


> This device is awesome and is a game changer with my amplifier shootout now.


Yes it is ... actually it is the ONLY way an equipment shoot out should be set up to get accurate results !!!
GREAT job getting it done !!!


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## JCsAudio (Jun 16, 2014)

seafish said:


> Yes it is ... actually it is the ONLY way an equipment shoot out should be set up to get accurate results !!!
> GREAT job getting it done !!!


Agreed, I wanted to do it like this before but wasn’t sure how to pull it off or wire it correctly and safely. If you do it incorrectly you can ruin your amplifiers within seconds if they connect outputs by accident. That’s tough to do when you have two amplifiers sharing the same speakers and you need to switch them as quickly as possible without letting them touch each other. With this new device though that can not happen and it switches amplifiers in fractions of a second so the music never even gets interrupted.

Still the previous tests are valid because I was able to devise a way to switch them within about 3 seconds and the results were very consistent amount different listeners but this new device will take any doubt away now.


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## seafish (Aug 1, 2012)

JCsAudio said:


> Still the previous tests are valid because I was able to devise a way to switch them within about 3 seconds and the results were very consistent amount different listeners but this new device will take any doubt away now.


LOL...Sorry...didnt mean to sound so harsh about the previous tests....I realize that you put alot of effort and time into making them valuable and, like you say, they still are.

That said, I MUCH prefer the format you are now able to do and it and it adds more validity to the value of what you are giving the community by doing this!!!

Just my .02


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## Bchester6 (Jan 15, 2020)




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## Alain93 (Mar 6, 2017)

Hi JC,
why did you said "I had to keep track of the button presses"?


Sent from my SM-T530NU using Tapatalk


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## Niebur3 (Jul 11, 2008)

^^^mot likely so he could keep track if Amp A or if Amp B was playing.


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## JCsAudio (Jun 16, 2014)

Alain93 said:


> Hi JC,
> why did you said "I had to keep track of the button presses"?
> 
> 
> Sent from my SM-T530NU using Tapatalk


Because the whole setup sits behind some wooden boards and all you see are the speakers. I hold a button in my hand and press it which switches amplifier A with amplifier B seamlessly. When I switch the amplifiers with the press of a button I can’t tell if they actually switched unless there’s an audible difference. During the switching of amplifiers the music is not interrupted. If I don’t keep track in my head the number of switches/button presses then I will lose track of which one is actually playing. At the end of the test I had to look behind the boards to verify I had kept track correctly. The relays do have LEDs on them that indicate which side is actually connected but they are hidden behind the wooden boards. I think I’m going to devise a way to install some separate LEDs that signify amplifier A or amplifier B is playing.


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## jtrosky (Jul 19, 2019)

Obviously, unless you have someone else connect the amps (if doing the listening test yourself) or have someone else doing the listening tests, then it's still not a true "blind" test though - and confirmation bias can still play a part - because if testing it yourself, you still know which is amp "A" and which is amp "B", right? Your mind will still know when the "cheap chinese" amp is active, which may skew the results.

This setup will be great for true "blind" testing if you have another subject do the listening while you do the switching - or someone else to connect them amps so that you don't know which amp is amp "A" and which is amp "B".

Unless I'm misunderstanding something...

I think that is why @Alain93 was asking why you were keeping track of which amp was active - as it "spoils" the "blind" part of blind testing. 

Sounds like a great way to do true "blind" testing though - if you have another participant!


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## JCsAudio (Jun 16, 2014)

jtrosky said:


> Obviously, unless you have someone else connect the amps (if doing the listening test yourself) or have someone else doing the listening tests, then it's still not a true "blind" test though - and confirmation bias can still play a part - because if testing it yourself, you still know which is amp "A" and which is amp "B", right? Your mind will still know when the "cheap chinese" amp is active, which may skew the results.
> 
> This setup will be great for true "blind" testing if you have another subject do the listening while you do the switching - or someone else to connect them amps so that you don't know which amp is amp "A" and which is amp "B".
> 
> ...


Sigh 😔 I did not know which one was playing when I started the test and just made an arbitrary guess and started keeping track. All I knew was which two amplifiers were behind the board but not which one was actually playing when I started the test. I wasn’t even sure the A/B switcher was actually working because there was no interruption in the music when I pushed the button. It is a very tough test for sure. You will be a believer if you try it, lol. 

Tough crowd here! No matter, I will use separate test subjects and they will have no idea what amplifier or amplifiers are connected behind the board. All they will see are two speakers, and two LEDs with the letters A or B under under each LED. When they push the button, one lit LED under A will switch to the other LED under B indicating that the amplifiers have switched from A to B. I can even disable the LED’s at first so they have no idea at all which one is actually playing and they would have to leave the speakers playing on the amplifier they prefer, assuming they can even decipher a dinference. The test subjects will not know which amplifier is A or B. Preferably, they will have no idea which amplifiers are even behind the board. All they will have is their ears, a push button in their hand, and two LEDs under the letters A or B indicating they have switched. 

I may bring the setup to the next meet and put those people to the test. Anyone want to bring their own amplifier and try it out? Anyone in New England want to try the test?


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## Alain93 (Mar 6, 2017)

jtrosky said:


> I think that is why @Alain93 was asking why you were keeping track of which amp was active - as it "spoils" the "blind" part of blind testing.


Exactly, , I was going to say to add a LED to know which one was selected but you said the relays have one. So it's easy to know the one you like most, just stop on it. 

Sent from my SM-T530NU using Tapatalk


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## JCsAudio (Jun 16, 2014)

Alain93 said:


> Exactly, , I was going to say to add a LED to know which one was selected but you said the relays have one. So it's easy to know the one you like most, just stop on it.
> 
> Sent from my SM-T530NU using Tapatalk


The relays are hidden behind the wood panel so you cannot see them when doing a demo and they only turn on when the relay‘s turn on so they do not indicate which amplifier is playing. I added LED’s that will indicate which amplifier is playing now.


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## Alain93 (Mar 6, 2017)

Would you do or be able to test DACs, drivers, mp3/flac, and more in the future? 

Sent from my SM-T530NU using Tapatalk


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## JCsAudio (Jun 16, 2014)

Alain93 said:


> Would you do or be able to test DACs, drivers, mp3/flac, and more in the future?
> 
> Sent from my SM-T530NU using Tapatalk


I’m sure I could devise a way to do a comparison but I would have to start a new thread for that. I did compare MP3 formats to each other a while back like 128k, 256k, and 320k to lossless and except for the lowest formats I couldn’t tell a difference so I abandoned it.


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## mrexcitement (Jan 23, 2019)

If they are the same quality class amp then the amp part should all sound the same , I believe the differences we hear between amps is differences in the internal preamp section that drives the amps main transistors.
In all my years of playing with home/car audio the differences I have heard have always been due to differences in the internal low voltage preamp section that drives the power amp section.

Wow , I am very surprised you can't hear the difference between 320k and lossless , to me it's very noticeable , with mp3 the bass is muddy , stereo imaging is not as good and the clarity is just not the same as the lossless version , the louder you go the easier it is to hear this difference.


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## Alain93 (Mar 6, 2017)

@mrexcitement These 2 files were the same song and made from the same source? Did you make them yourself?


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## Sam Spade (Mar 16, 2020)

Can you post the AB switch design for dummies build sheet?

Congrats BTW real commitment and if you press the button randomly and lose track of which amp is which it's definitely blind. 

Especially if you are over 50 🤣🤣🤣


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## JCsAudio (Jun 16, 2014)

mrexcitement said:


> If they are the same quality class amp then the amp part should all sound the same , I believe the differences we hear between amps is differences in the internal preamp section that drives the amps main transistors.
> In all my years of playing with home/car audio the differences I have heard have always been due to differences in the internal low voltage preamp section that drives the power amp section.
> 
> Wow , I am very surprised you can't hear the difference between 320k and lossless , to me it's very noticeable , with mp3 the bass is muddy , stereo imaging is not as good and the clarity is just not the same as the lossless version , the louder you go the easier it is to hear this difference.





Alain93 said:


> @mrexcitement These 2 files were the same song and made from the same source? Did you make them yourself?



Guys,

Please leave the MP3 file format debate for another thread.

Thanks


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## Picassotheimpaler (Sep 21, 2014)

JCsAudio said:


> Sigh 😔 I did not know which one was playing when I started the test and just made an arbitrary guess and started keeping track. All I knew was which two amplifiers were behind the board but not which one was actually playing when I started the test. I wasn’t even sure the A/B switcher was actually working because there was no interruption in the music when I pushed the button. It is a very tough test for sure. You will be a believer if you try it, lol.
> 
> Tough crowd here! No matter, I will use separate test subjects and they will have no idea what amplifier or amplifiers are connected behind the board. All they will see are two speakers, and two LEDs with the letters A or B under under each LED. When they push the button, one lit LED under A will switch to the other LED under B indicating that the amplifiers have switched from A to B. I can even disable the LED’s at first so they have no idea at all which one is actually playing and they would have to leave the speakers playing on the amplifier they prefer, assuming they can even decipher a dinference. The test subjects will not know which amplifier is A or B. Preferably, they will have no idea which amplifiers are even behind the board. All they will have is their ears, a push button in their hand, and two LEDs under the letters A or B indicating they have switched.
> 
> I may bring the setup to the next meet and put those people to the test. Anyone want to bring their own amplifier and try it out? Anyone in New England want to try the test?


Where are you in NE? I would actually love to check out this setup and just test it out first hand!


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## mrexcitement (Jan 23, 2019)

Alain93 said:


> @mrexcitement These 2 files were the same song and made from the same source? Did you make them yourself?


Sorry , I have no idea what you are referring to , I just commented on my own personal experience to what I believe is the difference between the sound from amps.


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## Holmz (Jul 12, 2017)

Sam Spade said:


> Can you post the AB switch design for dummies build sheet?
> 
> ...


Some of these should do it?


https://www.electroschematics.com/dpdt-switch-relay/



One would need some power resistors thrown in as well.


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## JCsAudio (Jun 16, 2014)

Worcester MA area, look for the next Northeast GTG meet in the spring where I may try this out with the group.


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## JCsAudio (Jun 16, 2014)

Ok, I have run the first test batch of amplifiers. I used the two previous contenders, the old school and good sounding Alpine 3548 and the Alpine MRP F-240. The 3548 is rated for 60W x 2 and the MRP F-240 40W x 4. This time the MRP F-240 sounds much better so I am wondering if I did something wrong in the previous tests where it didn’t fair so well. I ran these two baseline amplifiers because I still have them, and I needed some amplifiers to use with the new amplifier switching device to test it out. I created a video that illustrates and shows you my home made (I know its crude) amplifier switching device that allows me to seamlessly switch between amplifiers with the press of a button. Like before I level matched the amplifiers and used my very good sounding KEF C45 speakers to perform the test.

Amplifier A = Alpine MRP F-240

Amplifier B = Alpine 3548



*Wife:*

Amplifier A (MRP F-240) Sounds hollow and flat. Symbols do not sound as good.

Amplifier B (3548), voices sound better and fuller with more body. A is a little louder in the crescendo and has a tiny bit more echo.

Winner amplifier B

*Me:*

Amplifier A (MRP F-240), compared to amplifier B, amplifier A has a tab less clarity in the vocal range. I had to switch back and forth often though to decipher a difference.

Amplifier B (3548), has a better and slightly more dynamic bass response and the midrange and male vocal range comes through clearer.

Winner amplifier B



*Daughter:*

Amplifier A (MRP F-240), a bit more dull sounding compared to B. More of an echo, clearer in some songs. Voice more clear and I can hear them better. Couldn’t make out the tiny ticks and smaller sounds as much. Bigger sounds were more separated and detailed so you could make them out better. Sounded like it was more around my ears and not just coming straight at me.

Amplifier B (3548), Every sound you can make out from the others. More of a softer sound to it. Detail is better in this one including the tiny/small sounds.



Winner, amplifier B because she just liked the way the sounds flowed around her.



*Son:*

Amplifier A (MRP F-240), Music sort of clearer or clearer than B. Vocals a bit better than A

Amplifier B (3548), B has more bass than A.

Winner amplifier A

Previous to the test above with the new amplifier switching device, I ran an Mmats 6150D in the older style test where I had to manually switch the amplifiers within a few seconds. Unfortunately, I cannot certify that test as accurate because there was an issue with the amplifier that may have affected the result, making it an unfair and invalid test. Its too bad because I was really looking forward to putting the Mmats to the test. My initial thoughts for what its worth (not a good test) is that the Mmats sounds exceptionally good but does not stand out as the superior choice compared to the top contenders that have gone through in these tests. Please keep in mind I only ran it against the MRP F-240 and nothing else and I had to throw out that test because of the issues I was having. I no longer have the Mmats 6150D now. 

The video is located here: 



Here is the level matched results from REW for this test.


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## JCsAudio (Jun 16, 2014)

Next up is the JL Audio Vxi800/81. Here it is level matched to the old school Class A/B Alpine 3548.


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## JCsAudio (Jun 16, 2014)

I've been running some preliminary testing with just myself while turning off the A and B LED's so I don't know which amplifier is playing. When I know which amplifier is playing I prefer the JL, but when I try to pinpoint which one is playing without knowing it I only choose the JL 50% of the time. I think I notice just the slightest, tiniest improvement in detail for the JL. The weirdest part is when I play the first few seconds of Boomerang by Imagine Dragons Origins, and the tiny small tick in the beginning consistently images from the right with the Alpine, but when playing the JL it images from the left and sounds just a tad more detailed. I've tripled checked that the left and right speakers are not mixed up between amplifiers so this one is a mystery for now. My son just went to bed so no more testing tonight. I'll run some more tests tomorrow. This is a very tough test to do.


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## seafish (Aug 1, 2012)

JCsAudio said:


> When I know which amplifier is playing I prefer the JL, but when I try to pinpoint which one is playing without knowing it I only choose the JL 50% of the time.


I love this statement as it entirely justifies all the efforts you made on your new blind testing procedure and, in fact should probably be written in capital letters. Just my .02.


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## JCsAudio (Jun 16, 2014)

seafish said:


> I love this statement as it entirely justifies all the efforts you made on your new blind testing procedure and, in fact should probably be written in capital letters. Just my .02.


Thanks sea fish. I think the real test will be if I bring this thing to a meet with members from this Forum there and they get to experience the same thing.


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## seafish (Aug 1, 2012)

sent ya a pm


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## Bchester6 (Jan 15, 2020)

Fine job sir.


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## Picassotheimpaler (Sep 21, 2014)

JCsAudio said:


> Worcester MA area, look for the next Northeast GTG meet in the spring where I may try this out with the group.


Please do. I missed the meet this year due to some family issues. Definitely plan to make it out this year. Excited to get the chance to demo this set up.
Down in bristol if you ever want a hand with some testing.


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## JCsAudio (Jun 16, 2014)

Ok, I have on the test bench a JL Audio VXI800/8i pitted up against a HELIX P6 Mk2. Using my amplifier switcher to seamlessly switch between amplifiers without knowing which brand amplifier is playing I have run a test with my daughter and myself for now. I need to get a few more tests in but I can tell you these two DSP amplifiers are very close in a lot of ways and not as close in others. It is getting harder and harder for me to find the time to run these tests due to my kids getting older and having more activities, and my wife now works for the WooSox organization.

Amplifier A = JL Audio VXI 800/8i

Amplifier B = HELIX P6 Mk2

*Wife:*
Not tested yet but coming


*Daughter:*

Amplifier A (JL Audio VXI 800/8i),
The background noise is a tiny bit louder and I can hear it better. I can hear the singing (vocals) better because it separates their singing better than B does.

Amplifier B (HELIX P6 Mk2), This one is quieter with background noise within the recording and you can hear each background noise separately better, it separates it better.

Conclusion: Both are very close, but I prefer amplifier A over amplifier B.


*Me:*
Amplifier A (JL Audio VXI 800/8i), This amplifier has a nice wide full stage with good depth. Some songs I can barely tell a difference while with others the difference jumps out, especially within the vocal range. Vocals seem slightly more present with amplifier A.

Amplifier B (HELIX P6 Mk2), After taking the test I understand what my daughter meant by background noise being more present. The overall stage and depth are less with amplifier B. This is noticeable mostly in perceived midrange frequencies.

Conclusion: Both have very good detail and bass response and both sound very good, but amplifier B seems a little less on point with convincing me I am actually there with the singer. The stage width for the first time in these tests seems noticeably less with amplifier B. After the test I had to double check the left and right speaker levels to make sure everything was playing as it should be and equally. Sometimes when I switch from B to A, depending on the song, I get goosebumps right after the switch. I obviously prefer amplifier A.


*Son:*
Not tested yet.

Here is the unaltered raw REW frequency response with no EQ of any kind applied to either.









To make sure that there was nothing going on between the left and right channels, I measured the responses for the left side and right side separately by just disconnecting one speaker cable, or the other from the back of the speaker. Here is how those look. Here is the right speaker only.








Here is the left speaker only.









Many amplifiers I've run in these test didn't present much difference in terms of stage width unless I screwed something up, but in this test with certain songs and within the midrange and vocal frequencies I could hear the difference. More tests are comeing with these two. If I can get my wife to do the test then that will make this more conclusive as she obviously has experienced ears, but she also loves music too.


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## JCsAudio (Jun 16, 2014)

Some interesting notes about the test. After about 45 minutes of spirited play I checked amplifier temperatures with an infrared temperature gun and the JL was reading 94 degrees while the Helix was at 101 degrees. After sitting idle for about 25 minutes the JL was at 100 degrees (yes hotter) and the Helix cooled down to 86 degrees. So the helix seems to be more efficient when under a light load, or sitting idle, but the JL runs cooler when under a higher load.


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