# Who’s gone from class AB to class D amps and been happy?



## rob3980 (Jun 11, 2010)

Just curious to you SQ guys who has gone from class AB amps to class D amps and been just as happy with the sound quality ? 

I’m about to get rid of both my Escalade and Pacifica and get into a new 19 Ram and there’s not a lot of room behind the seats and I also don’t want to strain the electrical system like I am in my Escalade with 3 Mosconi Zero amp. I also don’t want to do a battery , alternator ect. 

I currently am running Mosconi Zero 4 x2 and a Mosconi Zero 1 in my Escalade and even with a xs battery it needs a alternator and I don’t want to do that in the new car. In my van I’m running a Zapco 150.6lx and 400.2lx and the stock electrical holds up to that ok but the amps are obviously large and eventually I plan to do a center channel when Af finally comes out with their DSP. 


So is there anyone out there that has run Mosconi as or zero and Zapco lx or ap Amps and then switched to class D and been just as happy? 

I’m doubting anyone has but I have to ask


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## JimmyDee (Mar 8, 2014)

*Re: Who’s gone from class AB to class D amps and been happy?*

I went from Zapco Z150.6-LX to MMATS HiFi-6150D. 

I'd say the MMATS sound every bit as good as the Zap did... Not better. Definitely not worse.


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## JimmyDee (Mar 8, 2014)

*Re: Who’s gone from class AB to class D amps and been happy?*

The advatage (for me) was the compact size of the Class D. 
And... they don't get hot.

In answer to your question; Yes, I am happy with the swap.

Although I still drool over the elite Class AB amps (like the new Brax MX4-Pro)


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## rob3980 (Jun 11, 2010)

Space is my issue and the strain that having 3 class ab amps puts on the electrical system. My 15 Escalade has a xs battery and big 3 upgrade and it’s not even close to enough.


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## rob3980 (Jun 11, 2010)

My plan is to run a 3 way active front stage with rear fill and when Audiofrog finally comes out with the dsp that will do a center channel I will add a 2 way active center channel. I’m not sure I could fit 3 class ab amps behind the seats. Which is why I am asking about the class d amps.


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## miniSQ (Aug 4, 2009)

*Re: Who’s gone from class AB to class D amps and been happy?*

Helix P-Six sounds as good as Mosconi.


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## Bayboy (Dec 29, 2010)

Space savings and efficiency trumps any sonic signature I've ever experienced. Perhaps my hearing isn't as sharp as others but I consider that a blessing to be honest. There's a lot of nice small package amps I'd hate to miss out on. 

Sent from my SM-G955U using Tapatalk


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## JCsAudio (Jun 16, 2014)

I bench tested several lesser amplifiers than these against an old school class AB made in Japan and the differences are so small that you really cant tell. The test was done blind with my wife telling me what she preferred and she did pick the class AB 100% but she struggled to do so and I couldn't tell myself. Speakers were Kef C-45 and all amplifiers were level matched to rule that out.


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## SPAZ (Jan 7, 2009)

*Re: Who’s gone from class AB to class D amps and been happy?*

I did a compare between an old school zapco a/b amp, mosconi a/b amp and the jl audio hd600/4. Decided to keep the 600/4 and still going strong in my setup. I just don't think amps make that much of a difference, sound wise as long as it is high quality. I also have been slowly moving over to class D/H products at home now as well.


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## rob3980 (Jun 11, 2010)

One thing I’m noticing is the class D amps I’ve looked at like the Helix P6 , JL Vxi and audio control amps aren’t rated very high rms. Is 120rms going to be enough power on my GB60s? 

I don’t really want to do amps with a built in dsp because as soon as audio frog comes out with the dsp that will do the center channel I’ll be switching to that dsp.


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## I800C0LLECT (Jan 26, 2009)

*Re: Who’s gone from class AB to class D amps and been happy?*

I used a JBL MS-A1004 on my GB60s and a JL hd900/5. C weighted measurements on my radio shack meter said low 120dB's and as high as mid 130s. They were in small sealed boxes

I think 120 is plenty for them

Sent from my ONEPLUS A6013 using Tapatalk


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## PPI_GUY (Dec 20, 2007)

If you don't ever plan on competing I can't imagine why you would run class a/b amps. Any difference is probably never going to be heard driving around in traffic and with road noise. The space savings and efficiency/ease on electrical are also great selling points. 
Having said all of that I have a bunch of old school class a/b amps and the only reason I run them is for nostalgia purposes.


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## rob3980 (Jun 11, 2010)

PPI_GUY said:


> If you don't ever plan on competing I can't imagine why you would run class a/b amps. Any difference is probably never going to be heard driving around in traffic and with road noise. The space savings and efficiency/ease on electrical are also great selling points.
> Having said all of that I have a bunch of old school class a/b amps and the only reason I run them is for nostalgia purposes.


I was always under the impression that class D can’t compare with ab but recently am hearing that the new class d amps are much improved. I just listed all my car audio I have for sale and am starting fresh. I honestly don’t know anything about the class D amps as I wrote them off years ago.


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## ckirocz28 (Nov 29, 2017)

rob3980 said:


> Just curious to you SQ guys who has gone from class AB amps to class D amps and been just as happy with the sound quality ?
> 
> I’m about to get rid of both my Escalade and Pacifica and get into a new 19 Ram and there’s not a lot of room behind the seats and I also don’t want to strain the electrical system like I am in my Escalade with 3 Mosconi Zero amp. I also don’t want to do a battery , alternator ect.
> 
> ...


I just pulled out my last A/B amp and replaced it with a D class, no difference at all. Memphis Audio MCX4.75 to JL Audio XD 400/4. I don't imagine the high end Italian and German equipment could be worse. Go ahead and switch.


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## rob3980 (Jun 11, 2010)

I see there is class d and then class d hd what’s the difference ?


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## GEM592 (Jun 19, 2015)

There are alot of great class D SQ options available, but also AB. No need to throw one out for the other, if space/etc is a serious concern by all means.


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## TomT (May 19, 2005)

*Re: Who’s gone from class AB to class D amps and been happy?*



rob3980 said:


> My plan is to run a 3 way active front stage with rear fill and when Audiofrog finally comes out with the dsp that will do a center channel I will add a 2 way active center channel. I’m not sure I could fit 3 class ab amps behind the seats. Which is why I am asking about the class d amps.


I’ve been running three large class A/B amps (and one class D sub amp) for a few years in my ‘15 Ram Crew Cab. The electrical is stock and I’ve never had any type of issue. System is a Sinfoni 4 channel, a pair of TRU Billets (swapped in a Brax MX2 for a while on midbass) and a Zapco class D sub amp.


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## rob3980 (Jun 11, 2010)

TomT said:


> rob3980 said:
> 
> 
> > My plan is to run a 3 way active front stage with rear fill and when Audiofrog finally comes out with the dsp that will do a center channel I will add a 2 way active center channel. I’m not sure I could fit 3 class ab amps behind the seats. Which is why I am asking about the class d amps.
> ...


I’m 90% positive its the zero1 sucking all my juice lol thing is a monster.


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## quickaudi07 (May 19, 2010)

When you bought the amp from me. I told you before you even bought it . That amp need juice... And you said you got it all day long lol. Looks like the juicer is running out of flavor quiet fast lolz.. either way.. zero1 needs ton of power. Love the amp... But dam ... It's demanding!

Sent from my Pixel 2 XL using Tapatalk


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## rob3980 (Jun 11, 2010)

quickaudi07 said:


> When you bought the amp from me. I told you before you even bought it . That amp need juice... And you said you got it all day long lol. Looks like the juicer is running out of flavor quiet fast lolz.. either way.. zero1 needs ton of power. Love the amp... But dam ... It's demanding!
> 
> Sent from my Pixel 2 XL using Tapatalk


Running out of juice and out of room. Not quite as much room behind the rear seat of a Ram vs a Escalade esv lol


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## rob feature (Nov 15, 2015)

No more A/B for me. I've noticed no downgrade in switching all over to D. Plus with my weak charging system it's the only way I can use the kind of power I like to use. I'd need to upgrade the electrical to use A/B. Then there's space. I need to mount 2 amps & power distro under the seats so they need to be pretty small. I could never do that with A/B. They run cooler too. Win, win, win. In my experience with Class D, A/B holds no advantage between the 2.


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## Holmz (Jul 12, 2017)

*Re: Who’s gone from class AB to class D amps and been happy?*



TomT said:


> I’ve been running three large class A/B amps (and one class D sub amp) for a few years in my ‘15 Ram Crew Cab. The electrical is stock and I’ve never had any type of issue. System is a Sinfoni 4 channel, a pair of TRU Billets (swapped in a Brax MX2 for a while on midbass) and a Zapco class D sub amp.


One can make a cogent argument for 4 or 6 low power channels of Class-AB and a subwoofer channel in Class-D.
(Which Tom has also shown by example)

Other home combos seen in the past have been tetrode to tweeters, pentode to mid range, and class AB to woofers.

...

Running a 2x50 Class-AB to 8 ohm tweeters, and a 4x100 Class AB to MR and woofers myself.


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## rob3980 (Jun 11, 2010)

I could keep some of my Class AB amps for tweets and mids and Run a D on the subs and I’d probably be fine but for whatever reason mixing amps would annoy the heck out of me even though I don’t look at them. Same with mixing speakers.


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## Mullings (Jan 31, 2016)

Well different experience here, I replaced 2 McIntosh mc431’s for 2 hd600/4’s and couldn’t reach home fast enough to switch them back, then my boss at that time gave me 2 focal fdp 600/4 to try and after level matching and a few of my all time favorite demo track I took them right back out. Now that I have the opportunity to work with super high end equipment I’ve found some rivals to the McIntosh and it turns out that none of them are class d, arc se, sinfoni amplitude, brax mx, phass re, just to name a few.


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## rob3980 (Jun 11, 2010)

I also didn’t like my JL HD amps but then again the tuner I had was a great installer and not good at tuning so I’m not sure it it was more him than the amps lol


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## Porsche (Jun 29, 2008)

class a or a/b anyway, the very best will outperform class d anyday IMO if set up and calibrated correctly, of course everything in the system has to be upto par to hear all the dynamics and nuances of a highend class a and a/b amp, i think this is where most miss the boat that claim they cant tell a difference, i would look at the whole system, not just the amp/s


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## JimmyDee (Mar 8, 2014)

These will not disappoint...

https://www.mmatsproaudio.com/site/product-category/amplifiers/hifi/

https://www.mmatsproaudio.com/site/product-category/amplifiers/m/


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## Mullings (Jan 31, 2016)

i Didn’t want anyone to think that I’m taking a jab at their system so I left out what Porsche said about the rest of the system not being up to par, some people just use a piece of equipment because it does what I was designed to do and not what it’s supposed to do, i demo’d a car at last finals and ask the owner if he was using class d amplifiers and he said “yes but you can’t tell the difference “ and thought the amplifier doesn’t tell the whole story, he got beaten by the class ab competitors. I just wrote and deleted a whole paragraph about a speaker that people here says is amazing that is so far off from the True Tone but I won’t do any brand bashing. My point is that people can say anything till you actually get some seat time in their vehicle and found out that it’s far from what the owner described.


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## rob3980 (Jun 11, 2010)

As far as the being up to par please explain?


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## JCsAudio (Jun 16, 2014)

*Re: Who’s gone from class AB to class D amps and been happy?*



Mullings said:


> Well different experience here, I replaced 2 McIntosh mc431’s for 2 hd600/4’s and couldn’t reach home fast enough to switch them back, then my boss at that time gave me 2 focal fdp 600/4 to try and after level matching and a few of my all time favorite demo track I took them right back out. Now that I have the opportunity to work with super high end equipment I’ve found some rivals to the McIntosh and it turns out that none of them are class d, arc se, sinfoni amplitude, brax mx, phass re, just to name a few.


Trick is you have to audition them level matched and not knowing which one is installed. That would be the true test, otherwise the brain plays nasty tricks on you and it will pick what it wants to.


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## Mullings (Jan 31, 2016)

Someone once didn’t believe that I could tell the difference between all of jl line of amplifiers till we did a blind test and I was able to 100% tell what amp was playing a pair of C5 component,anyone that says all amps sounds the same and only amplify the signal is just inexperienced, people with more experience would know that switching an amp affects stage/image differently and wouldn’t pickup on with inexperienced ears, I once put in place a helix a4 amp in place of my beloved slash 300/4 and my stage went from close to the windshield to beyond it and sound from the drivers sounded like it’s coming from behind them all while being less efficient than the jl, the average guy would say this amp isn’t powerful enough and take it out.


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## JCsAudio (Jun 16, 2014)

*Re: Who’s gone from class AB to class D amps and been happy?*

Well this is getting interesting! To Mullings point and Porsche there might be more to this than I have the means to address. I have 220 amps of clean power supply available and the only decent class AB amplifiers I have now are an old school Alpine 3548 (won out in my blind shootout) and hopefully the RF ti600, which I havent tested yet but now I want to. Maybe we should put our resources together and go for another amplifier shootout. I found differences in my amplifiers too, mainly the cheaper older ones lost out but those cant compare to the ones you guys are looking at.


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## Patriot83 (May 10, 2017)

*Re: Who’s gone from class AB to class D amps and been happy?*

Below is an excerpt from audioholics talking about dynamics. Everyone hears different things in different ways. I've heard class D systems that sounded VERY clean but something was just missing. Very hard to explain. Don't know if this could be it. 

"Ultimately, the complexity of Class D has its rewards: efficiency, and as a good consequence, less weight. As relatively little energy is wasted as heat, much less heat sinking is required. Ratcheting that up a notch, many Class D amplifiers are used in conjunction with switch mode power supplies (SMPS). The disadvantage of SMPS power supplies over traditional linear supplies is the former typically don't have much dynamic headroom. Our limited testing of Class D amps with linear supplies vs SMPS supplies have shown this to be true where two comparably rated power amps both delivered rated power, but the one with the linear supply was able to produce higher dynamic power levels". (Audioholics)


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## rob3980 (Jun 11, 2010)

V8toilet said:


> Well this is getting interesting! To Mullings point and Porsche there might be more to this than I have the means to address. I have 220 amps of clean power supply available and the only decent class AB amplifiers I have now are an old school Alpine 3548 (won out in my blind shootout) and hopefully the RF ti600, which I havent tested yet but now I want to. Maybe we should put our resources together and go for another amplifier shootout. I found differences in my amplifiers too, mainly the cheaper older ones lost out but those cant compare to the ones you guys are looking at.


Didn’t Matt Hall do a shootout and the jl class D was in the bottom tier if I remember correctly ???


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## B5I8 (Feb 7, 2009)

*Re: Who’s gone from class AB to class D amps and been happy?*



jimmydee said:


> These will not disappoint...
> 
> https://www.mmatsproaudio.com/site/product-category/amplifiers/hifi/
> 
> https://www.mmatsproaudio.com/site/product-category/amplifiers/m/


I've got (2) HiFi-4250D's and (1) HD4000.1 sitting in my garage waiting to be installed this upcoming weekend. Purchased from David Thompson and fresh off the production line. They are so small for the amount of power they're rated at. More than enough power to run any combination of speakers even for any bass-heads out there.


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## Porsche (Jun 29, 2008)

*Re: Who’s gone from class AB to class D amps and been happy?*



V8toilet said:


> Well this is getting interesting! To Mullings point and Porsche there might be more to this than I have the means to address. I have 220 amps of clean power supply available and the only decent class AB amplifiers I have now are an old school Alpine 3548 (won out in my blind shootout) and hopefully the RF ti600, which I havent tested yet but now I want to. Maybe we should put our resources together and go for another amplifier shootout. I found differences in my amplifiers too, mainly the cheaper older ones lost out but those cant compare to the ones you guys are looking at.


sorry but i do not have to convince myself or anyone for my opinions and differences that i hear both in my home and multiple cars


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## JCsAudio (Jun 16, 2014)

*Re: Who’s gone from class AB to class D amps and been happy?*



Porsche said:


> sorry but i do not have to convince myself or anyone for my opinions and differences that i hear both in my home and multiple cars


Maybe there is a misunderstanding, I wasn't trying to change your mind. :shrug:


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## Porsche (Jun 29, 2008)

*Re: Who’s gone from class AB to class D amps and been happy?*



V8toilet said:


> Maybe there is a misunderstanding, I wasn't trying to change your mind. :shrug:


amplifier shootouts, whats the point, they prove absolutely nothing other than convincing some that all amps sound the same if scientifically controlled, blah blah blah


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## JCsAudio (Jun 16, 2014)

*Re: Who’s gone from class AB to class D amps and been happy?*



Porsche said:


> amplifier shootouts, whats the point, they prove absolutely nothing other than convincing some that all amps sound the same if scientifically controlled, blah blah blah


What about what Mullings said in that there are differences within the JL line of amplifiers to the trained ear. I also found differences in my comparison too but not with high end amps because I don't have access to them. Still the second runner up was the best class D I have so its apples to apples in the class I'm at for what that is worth. 

I do agree with what you originally stated in that the whole system has to be up to par.

Its tough to get straight answers where there is so much subjectivity and emotions involved with it I guess and instruments cant measure what people say is different. For most people buying an amplifier is an investment in their system where they can only buy a few. Its a blind purchase much like a mattress purchase where you cant see whats inside and know what part does what or if its good or not. Most people have to rely on the sales guy or subjective ratings and reviews to help them make their decision. Its the reason why you see these threads come up again and again. Then there is the fact that a high price tag is no guarantee you will get top dog performance from it. Worse thing for some would be to find out that the $2000 amplifier you saved up for and bought sounds no different than the $600 one you bought.

I'd personally like to see more people do some apples to apples comparisons in a controlled environment and share the results on the board for the benefit of all.


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## Rainstar (May 22, 2017)

*Re: Who’s gone from class AB to class D amps and been happy?*

the hell is class D, im the only D in my car.


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## Bayboy (Dec 29, 2010)

*Re: Who’s gone from class AB to class D amps and been happy?*



Porsche said:


> amplifier shootouts, whats the point, they prove absolutely nothing other than convincing some that all amps sound the same if scientifically controlled, blah blah blah


This is absolutely incorrect. The main and infamous challenge with that intention was Richard Clark's. There has been several "shootouts" and comparable reviews including Matt Hall's where the intentions were not to claim that all amps sound the same if tuned to be, rather comparing sonic attributes of amp offerings by tier which helped not only dispel the "sound alike" myth, but also aided in amplifier options for interested consumers. 



Sent from my SM-G955U using Tapatalk


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## Porsche (Jun 29, 2008)

*Re: Who’s gone from class AB to class D amps and been happy?*



Bayboy said:


> This is absolutely incorrect. The main and infamous challenge with that intention was Richard Clark's. There has been several "shootouts" and comparable reviews including Matt Hall's where the intentions were not to claim that all amps sound the same if tuned to be, rather comparing sonic attributes of amp offerings by tier which helped not only dispel the "sound alike" myth, but also aided in amplifier options for interested consumers.
> 
> 
> 
> Sent from my SM-G955U using Tapatalk


i could care less what matt hall does or what he thinks. amplifiers react different to different speakers, cables, source, etc etc etc unless its installed in my car i honestly do not care what matt or anyone else thinks/believes


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## rob3980 (Jun 11, 2010)

Porsche said:


> Bayboy said:
> 
> 
> > This is absolutely incorrect. The main and infamous challenge with that intention was Richard Clark's. There has been several "shootouts" and comparable reviews including Matt Hall's where the intentions were not to claim that all amps sound the same if tuned to be, rather comparing sonic attributes of amp offerings by tier which helped not only dispel the "sound alike" myth, but also aided in amplifier options for interested consumers.
> ...


Have you ever tried the Zero amps? Just curious as how they compare to the Zapco Ap amps? I’m debating sticking w class ap for my speakers and doing a class d for the subs. What are your favorite amps you have used ? 

So far mine are my Mosconi Zeros and LX amps that I currently am using. I would love to do all class d the size of the jl hd amps but im not convinced they can sound as good until I actually hear it in someone’s vehicle.


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## Zippy (Jul 21, 2013)

I actually started with class D amps in my BRZ. I was using 2 Hertz HDP4 amps. They were setup with each channel to a speaker at one point and a pair of channels bridged to my sub. They sounded ok. My RAV4 sounded better to my ears though with it's AB amps. I ended up swapping the HPD4 amps to 6 Bewith A110S II amps and a JL Slash series 600/1 for sub work. I dropped 50 watts a channel to the tweeters, mids, and midbass and I was loving how it sounded after. The biggest difference I noticed was the listed Damping Factor on the amps I went from and to. The HDP4 list 50 at 100Hz and 4 ohms while the Bewith amps listed 450 at 100Hz and 4 ohms. Ever since I have kept a close lookout for Damping factor. Most manufactures will not list it.

Side note: The Bewith amps are really small and light weight. They generate about the same heat as the class D amps I removed.


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## Frijoles24 (Apr 19, 2010)

*Re: Who’s gone from class AB to class D amps and been happy?*



Porsche said:


> i could care less what matt hall does or what he thinks. amplifiers react different to different speakers, cables, source, etc etc etc unless its installed in my car i honestly do not care what matt or anyone else thinks/believes


It is interesting to hear that from you, considering you have quite the gear in your possession. 

If they all sound the same, why do you have such expensive amps?


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## Porsche (Jun 29, 2008)

*Re: Who’s gone from class AB to class D amps and been happy?*



Frijoles24 said:


> It is interesting to hear that from you, considering you have quite the gear in your possession.
> 
> If they all sound the same, why do you have such expensive amps?


how did you read that i think they all sound the same, i said the opposite, they perform differently under different circumstances and conditions in the car


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## Bayboy (Dec 29, 2010)

*Re: Who’s gone from class AB to class D amps and been happy?*



Frijoles24 said:


> It is interesting to hear that from you, considering you have quite the gear in your possession.
> 
> If they all sound the same, why do you have such expensive amps?


He isn't saying all amps sound the same. What he is saying unless it's installed in his vehicle he doesn't give a flying rats ass what anyone thinks. I think that's a good suggestion in return. Why care about anything he thinks about gear unless it's in your vehicle as well??? 

Sent from my SM-G955U using Tapatalk


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## Frijoles24 (Apr 19, 2010)

Hahaha, reading into who said what, i am mixing people up. And just read the last one from Porsche. My apologies.

Thats what i get for skimming.


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## bluesman1 (Mar 2, 2010)

*Re: Who’s gone from class AB to class D amps and been happy?*

This is an interesting discussion because I don't think there were any full range class D amps out yet when I bought my last amp. I'm still running a JL 500/5 from 2002. It's got a class D sub section. I remember that these JL's were panned by some folks shortly after they came out. It replaced my US Amps when I downsized the system. There were definitely some sonic changes but the power level was way down and there were some other system changes made at the same time. Never thought the JL sounded bad though and I can't complain because I haven't had a single issue with the amp. 

Way back when I had been through Kenwood, Orion, Autotek, US AMPS and a couple others for amplification. It's been so long now that I don't have a point of reference aside from that 17 year old JL amp. Last system I put in from scratch was in my son's old Nissan maybe 8 years ago. That was a 4 channel A/B Alpine. I don't think I've even heard a class D amp in a car, other than on subs.


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## rob3980 (Jun 11, 2010)

Back in 2012 I had Jl c5s and. HD 900/5 and hated it with a passion. Then I tried it again in 2015 with my hertz Milles and the 900/5 again and still hated it. Switched to Mosconi as amps and had never been happier until my last 2 set ups which are now for sale


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## truckguy (Sep 2, 2013)

*Re: Who’s gone from class AB to class D amps and been happy?*

Rob, what is your entire plan for your truck? For a 3 way up front plus rear fill and a sub your going to need a lot of channels. The only way I can think of you fitting 2 large class a/b amps is if your sub enclosure is up front. You’d have room under your seat and rear wall for a processor and amps. 

I have a 17 Canyon running a Helix P6 Mk2 with an Arc SE2300 for sub duty. No rear fill. I like it. I’m sure a/b amps would sound slightly better but don’t have the room. Having a truck really limits what you can do. Best thing I ever did was give it to an installer and tuner who knew what they were doing.


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## speakerpimp (Feb 15, 2012)

I've ran several amps on my front stage over the past few years, and auditioned several more for short periods of time. Same head unit and dsp for most of that time as well. A couple were D topology. Most were VERY similar in sound without any discernible differences when graded on a curve for power output. The last "shootout" I did in my car was between a Tru Billet 4100 stage3, an AD 1000.4, and a Brax Matrix MX4. I actually favored the AD over the Tru, and thought to myself here I go to the "D"ark side. That is until I dropped in the Brax... noticeable difference right away. No going back.


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## rob3980 (Jun 11, 2010)

speakerpimp said:


> I've ran several amps on my front stage over the past few years, and auditioned several more for short periods of time. Same head unit and dsp for most of that time as well. A couple were D topology. Most were VERY similar in sound without any discernible differences when graded on a curve for power output. The last "shootout" I did in my car was between a Tru Billet 4100 stage3, an AD 1000.4, and a Brax Matrix MX4. I actually favored the AD over the Tru, and thought to myself here I go to the "D"ark side. That is until I dropped in the Brax... noticeable difference right away. No going back.


I have never heard a Brax but have only heard great things about them.


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## rob3980 (Jun 11, 2010)

truckguy said:


> Rob, what is your entire plan for your truck? For a 3 way up front plus rear fill and a sub your going to need a lot of channels. The only way I can think of you fitting 2 large class a/b amps is if your sub enclosure is up front. You’d have room under your seat and rear wall for a processor and amps.
> 
> I have a 17 Canyon running a Helix P6 Mk2 with an Arc SE2300 for sub duty. No rear fill. I like it. I’m sure a/b amps would sound slightly better but don’t have the room. Having a truck really limits what you can do. Best thing I ever did was give it to an installer and tuner who knew what they were doing.


My plan is to run a active 3 way front stage with active 2 way center channel and maybe rear fill. I have 2 JL Tw5 subs I’ll use. So I’ll need anywhere from 9-12 channels. I’ll be waiting for a dsp that will properly do a center channel to come out. I went to the dealer and checked out the space behind the seats today and i probably could fit the Zapco or Zero amps I have but I’m also interested in the MMATS amps that were mentioned possibly. Another possibility is run ab amps for the speakers and a class d for the sub. I’m about 90% sure I could fit 2 Zapco 150.6ap amps and a small class d for the subs. 

Speakers will be JL c7s or focal utopia M. I can get the c7s for about 35-40% off and from the 3 ppl I talked to that heard them and they have also heard a ton of other speakers they had nothing but great things to say about the c7s

If I don’t run rear fill i will probably run 2 Zapco 150.4 ap amps and a 1200rms class D amp for the tw5s


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## PPI_GUY (Dec 20, 2007)

I have a friend who is a JL Audio authorized dealer and when I say he is a dealer, I mean to say he moves a LOT of JL product. He told me face to face that he prefers the XD series over the HD by a good margin. This was before the RD series came out and although I haven't actually heard a JL RD amp in person, I have read a ton of first person opinions on them. Most all say they prefer the RD amps over the XD amps. 
What does all this tell us about the HD series? IMO it says there is a sizeable portion of interested consumers and at least one dealer who think JL offers better sounding amplifiers than the HD.

Personally, I don't know what to think. The XD and Rd amps both switch at the same 240 kHz. The RD is unregulated while the XD is tightly regulated. The HD amps switch at around 400 kHz and are tightly regulated. So, scientifically the HD amps _should_ sound better. And maybe to some they do? So, I guess we're down to fractions of a single percent making the difference...again, to some people.


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## ckirocz28 (Nov 29, 2017)

PPI_GUY said:


> I have a friend who is a JL Audio authorized dealer and when I say he is a dealer, I mean to say he moves a LOT of JL product. He told me face to face that he prefers the XD series over the HD by a good margin. This was before the RD series came out and although I haven't actually heard a JL RD amp in person, I have read a ton of first person opinions on them. Most all say they prefer the RD amps over the XD amps.
> 
> What does all this tell us about the HD series? IMO it says there is a sizeable portion of interested consumers and at least one dealer who think JL offers better sounding amplifiers than the HD.
> 
> ...


I can't comment on the HD amps, but I own an RD 400/4 and an XD 400/4. They sound exactly the same. The only differences I could make out from JL's specs are upgraded pots and switchable preouts, you may or may not be correct about the power regulation. At 80-100 bucks difference in price between the two, there isn't any real reason to pick the XD over the RD.


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## rob3980 (Jun 11, 2010)

I’ve actually heard that people that have had both prefer the xd over the hd. I ended up saying f it and grabbing another 150.4LX tonight so I’m keeping my 150.6lx and 400.2 lx . If it’s too much of a drain I’ll dump the 400.2 for a class d amp . Guess I’m old school and stuck in my ways lol. Now just gotta get the vehicle and wait for the dsp


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## rob feature (Nov 15, 2015)

*Re: Who’s gone from class AB to class D amps and been happy?*



rob3980 said:


> I’ve actually heard that people that have had both prefer the xd over the hd.


I've heard this too. I use the XDs and love them.


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## Hillbilly SQ (Jan 26, 2007)

Maybe the XD and RD add that little somethin somethin to the sound that a lot of people like? I do know when it comes to class d those two lines of amps are the only amps I feel like are worth having. This is all opinion and knowing that JL has enough integrity not to peddle junk like some companies do *cough* Epsilon *cough*. A few years back I replaced two Mosconi One 120.4's with a single XD800/8. The single 8ch wasn't as loud as the pair of lower end Mosconi amps but it seemed to have way better control of the speakers. And got plenty loud running an Audible Physics 3-way and sealed Arc 10. I've actually thought about going back to an 800/8 and running a ridiculously efficient 12" sub.

Someone stated the differences they could tell on RD vs XD and I'll add one more that I'm not too fond of. The RD crossovers can't be switched to "full". Just high and low. This is an issue for me because I have my RD900/5 bridged to my midbass drivers. Sure I just set the onboard crossover at around 70 (12db Linkwitz Riley slope) and run a 12db LR slope in the processor to combine the two wherever I see fit with no ill effects that I can tell but still bugs the crap out of me. I'd still buy an RD400/4 to go with my RD900/5 today if a nice clean one popped up in the classifiedsThey're great amps that seem to be built like a tank.


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## Bayboy (Dec 29, 2010)

That is one of the main things I like about the XD700/5.. defeatable sub xover which is rare for 5 channel amps. It's a simple amp that's able to do 3-way active on its on as well. A pretty neat package with good sound. Add a 200/2 or bridged 400/4 for midbass and you have a nice flexible package for a separate DSP. 

Sent from my SM-G955U using Tapatalk


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## JCsAudio (Jun 16, 2014)

The DLS did well in this comparison. https://www.dropbox.com/s/ttqllik75sefne2/High Value Amplifier Shootout.pdf?dl=0


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## Hillbilly SQ (Jan 26, 2007)

*Re: Who’s gone from class AB to class D amps and been happy?*



Zippy said:


> I actually started with class D amps in my BRZ. I was using 2 Hertz HDP4 amps. They were setup with each channel to a speaker at one point and a pair of channels bridged to my sub. They sounded ok. My RAV4 sounded better to my ears though with it's AB amps. I ended up swapping the HPD4 amps to 6 Bewith A110S II amps and a JL Slash series 600/1 for sub work. I dropped 50 watts a channel to the tweeters, mids, and midbass and I was loving how it sounded after. The biggest difference I noticed was the listed Damping Factor on the amps I went from and to. The HDP4 list 50 at 100Hz and 4 ohms while the Bewith amps listed 450 at 100Hz and 4 ohms. Ever since I have kept a close lookout for Damping factor. Most manufactures will not list it.
> 
> Side note: The Bewith amps are really small and light weight. They generate about the same heat as the class D amps I removed.


Bo, what kinda scratch do those BeWith amps cost? Being Japanese I'm sure they're built to sound as good as possible and last as long as possible.


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## bluesman1 (Mar 2, 2010)

Anyone have any experience with or opinions about the Alpine PDX-V9 5 channel?

The way that Alpines connections and controls are laid out are about perfect for the under seat install in my old Chevy truck and the power output is perfect for me as well. I don't need an amp but that Alpine layout is almost tailor made so it's tempting ... if it's any good.


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## Hillbilly SQ (Jan 26, 2007)

The new PDX amps are great amps.


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## Bayboy (Dec 29, 2010)

*Re: Who’s gone from class AB to class D amps and been happy?*



bluesman1 said:


> Anyone have any experience with or opinions about the Alpine PDX-V9 5 channel?
> 
> The way that Alpines connections and controls are laid out are about perfect for the under seat install in my old Chevy truck and the power output is perfect for me as well. I don't need an amp but that Alpine layout is almost tailor made so it's tempting ... if it's any good.


Clean, powerful sounding amp in my setup although it's only running small tweets, 2.5" fullrange as midrange, and a HO 10" sealed. A PDX-F4 is under the passenger seat bridged on 8's in the doors. 

Compared to the JBL MS combo it replaced, the bass seems more tightly controlled although I did like the brute low end the MS-A5001 exhibited on the same sub. It's not bad now, just more controlled yet still gets low with authority. Upper range sounds cleaner than the JBL's. I like the combo. 

Sent from my SM-G955U using Tapatalk


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## rob3980 (Jun 11, 2010)

I’m tempted to get some class d amps and try both in the vehicle. If class d sound as good as the zapcos or Mosconi zeros i would ditch the big amps in a heart beat. I’m just not convinced that these small amps that cost a fraction of what my amps cost can sound as good but I would love to try them out and be proven wrong. Would save a lot of headaches trying to fit big amps and upgrade electrical that is for sure.


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## Hillbilly SQ (Jan 26, 2007)

*Re: Who’s gone from class AB to class D amps and been happy?*



rob3980 said:


> I’m tempted to get some class d amps and try both in the vehicle. If class d sound as good as the zapcos or Mosconi zeros i would ditch the big amps in a heart beat. I’m just not convinced that these small amps that cost a fraction of what my amps cost can sound as good but I would love to try them out and be proven wrong. Would save a lot of headaches trying to fit big amps and upgrade electrical that is for sure.


Higher price doesn't guarantee better sound. I've run a lot of amps in my day with varying price points but the best sounding cost me less than $200 new. It's the Zapco ST-4x SQ that's running my midrange and tweeters. And it's hard to go wrong with the JL XD and RD amps. I hear the VXi amps with dsp in them sound more open than the XD and RD. Get you some VXi amps and you won't need any room hardly to fit them.


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## JimmyDee (Mar 8, 2014)

*Re: Who’s gone from class AB to class D amps and been happy?*



rob3980 said:


> I’m just not convinced that these small amps that cost a fraction of what my amps cost can sound as good but I would love to try them out and be proven wrong.


You'll never know until you try one...

The Zapco Z-LX and Z-AP are among the finest AB amps I've ever heard / owned. Definitely the best bang for the buck AB out there. 
If you can fit a pair of them in your new vehicle, and have the power to drive them, then there is no issue. You've got nice amps.

With that said (and I've said it before); 
If you actually tried a MMATS amplifier, which costs the same as a Zapco Z-LX, then you would find out how incredible they really are.
I'm only relaying my own personal experience, as I went from Zapco Z-LX to MMATS.

Don't get me wrong. I am still a huge fan of the Z-LX and Z-AP amps. They are fantastic, and I have no issue recommending them.
But for the reasons you stated (size limitations, power consumption); I'm not sure why you wouldn't have at least auditioned a top-tier Class D.


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## rob3980 (Jun 11, 2010)

jimmydee said:


> rob3980 said:
> 
> 
> > I’m just not convinced that these small amps that cost a fraction of what my amps cost can sound as good but I would love to try them out and be proven wrong.
> ...


The 3 lx amps i wanted to run won’t fit so class d it will have to be. Who’s got the cheap plug on MMATS around here ? I need 10 channels and a sub amp


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## Mic10is (Aug 20, 2007)

Sold my Helix DSP Pro...so I needed music in my car...bought the new Arc Audio PS850.
It's 50x8 which channels 7/8 rca output to an amp w a PS8pro DSP built in.

I am thoroughly impressed.
This replaces 2 modified Arc Se4200 on my front stage.

Besides the amount if tuning flexibility and options the PS8pro offers the amp is sonically really nice. Very detailed and accurate.


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## gijoe (Mar 25, 2008)

I swapped out a Zuki Eleets 4 channel for the new PDX line, and never had a single regret. I miss the Zuki from a nostalgic standpoint, but would never use one again when the same quality can be had in a much smaller, efficient package. The days of using AB amps in the car are over for me. 

Read opinions on the inferiority of class D amps with caution, and skepticism. These days class D can be every bit as good, but even 10 years from now there will be a stubborn group that won't believe they are as good as AB and will refuse to use them.


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## Hillbilly SQ (Jan 26, 2007)

The first run of pdx amps were pretty bad. I ran a first gen pdx5 I bought from an old buddy of mine and sold it back to him it sounded so bad. As far as a/b vs d for me it's all in what fits the install goals the best. More times than not if I run an a/b amp it's because I can, not because I think class d is inferior because it's not. I just feel like it's a lot easier to find a poorly designed and sounding class d. Technology has changed huge over the past 10 years and will probably change for the better 10 fold over the next 10 years.


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## rob3980 (Jun 11, 2010)

I’ve got my eyes set on the Mmats amps going to run 1 hifi 6150d and 2 hifi 4250d’s If I can get a good price on them. The 6150 will run my tweets and 3” for my front stage and center channel. One of the 4250s will run my mid bass and the rear fill and the other 4250 will run 2 Tw5 subs. 

We will see how these stack up to my Zero and LX amps soon enough. I will be sure to leave my opinion on them once I’ve listened to them for a few months .


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## bluesman1 (Mar 2, 2010)

*Re: Who’s gone from class AB to class D amps and been happy?*



rob3980 said:


> I’ve got my eyes set on the Mmats amps going to run 1 hifi 6150d and 2 hifi 4250d’s If I can get a good price on them. The 6150 will run my tweets and 3” for my front stage and center channel. One of the 4250s will run my mid bass and the rear fill and the other 4250 will run 2 Tw5 subs.
> 
> We will see how these stack up to my Zero and LX amps soon enough. I will be sure to leave my opinion on them once I’ve listened to them for a few months .


I noticed that 6150D a little while back. That's another amp that's laid out perfectly to suit my situation. But I spend so little time in the vehicle these days that it would be real hard to justify the price. I'm probably going to end up running my old JL until it dies but I'm intent on trying to figure out and keep up with what's going on with the current stuff. I haven't messed with the system much at all since 2002.


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## bluesman1 (Mar 2, 2010)

*Re: Who’s gone from class AB to class D amps and been happy?*



gijoe said:


> I swapped out a Zuki Eleets 4 channel for the new PDX line, and never had a single regret. I miss the Zuki from a nostalgic standpoint, but would never use one again when the same quality can be had in a much smaller, efficient package. The days of using AB amps in the car are over for me.
> 
> Read opinions on the inferiority of class D amps with caution, and skepticism. These days class D can be every bit as good, but even 10 years from now there will be a stubborn group that won't believe they are as good as AB and will refuse to use them.


I'm old school. Aside from the vehicle and the budget home theater receiver, just about everything I have is tubes. I don't think I've ever heard a full range class D. All I know is that they weren't ready for prime time when I last changed the mobile system. I have nothing against them, I just don't know much about them.


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## rob3980 (Jun 11, 2010)

3 MMATS hifi amps ordered and shipping tomorrow. Let’s see what these things are all about


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## gijoe (Mar 25, 2008)

*Re: Who’s gone from class AB to class D amps and been happy?*



bluesman1 said:


> I'm old school. Aside from the vehicle and the budget home theater receiver, just about everything I have is tubes. I don't think I've ever heard a full range class D. All I know is that they weren't ready for prime time when I last changed the mobile system. I have nothing against them, I just don't know much about them.


Plenty of people don't have anything against them, but they do remember the old days when class D wasn't up to the task of fullrange sound reproduction. This memory of the downfalls of old class D influence people's decisions now, and not matter how good class D gets there will be people who are convinced that they are inferior. I'm certainly not saying you, or anyone else in particular falls into this group, I am simply saying that nostalgia and perceptual bias plays a huge role in this hobby. 

Again, I'm just encouraging people to have a healthy dose of skepticism towards the people who claim class D is still inferior. When people are winning world class championships with class D amps, maybe AB just isn't sonically superior anymore.


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## Redliner99 (Mar 26, 2018)

rob3980 said:


> I’ve got my eyes set on the Mmats amps going to run 1 hifi 6150d and 2 hifi 4250d’s If I can get a good price on them. The 6150 will run my tweets and 3” for my front stage and center channel. One of the 4250s will run my mid bass and the rear fill and the other 4250 will run 2 Tw5 subs.
> 
> We will see how these stack up to my Zero and LX amps soon enough. I will be sure to leave my opinion on them once I’ve listened to them for a few months .




Call mmats directly and talk to them should give you a good price. 


Sent from my iPhone using Tapatalk


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## TaylorMade (Feb 11, 2017)

*Re: Who’s gone from class AB to class D amps and been happy?*

lol looks like he already ordered them. He probably called them anyways.

I'd be curious to know how this turns out. I remember Mmats from way back in the day when all that my friends and I cared about was how hard does it bump. They were well known for that.

But, I've heard nothing but good things about those amps though. Never seen any reviews on them, or read about any of them being in a "shootout" of sorts. Curious if someone could way in on that.


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## rob3980 (Jun 11, 2010)

bluesman1 said:


> gijoe said:
> 
> 
> > I swapped out a Zuki Eleets 4 channel for the new PDX line, and never had a single regret. I miss the Zuki from a nostalgic standpoint, but would never use one again when the same quality can be had in a much smaller, efficient package. The days of using AB amps in the car are over for me.
> ...



From what a lot of people on here are saying that have experience with them class D has come a long way. Like I said I ordered 3 of them so I will find out soon. I’ll be pretty disappointed if they aren’t as good as people say but I won’t be shocked.


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## JCsAudio (Jun 16, 2014)

The amplifier that did the worst in my blind test was an Alpine class AB design.


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## K-pop sucks (May 28, 2018)

I won't go class D anytime soon. Just another way for manufacturers to cut corners and increase profit margins. AB is superior to class D any day of the week.

I'll stay true to class AB in my car and class H or AB at home.


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## JimmyDee (Mar 8, 2014)

*Re: Who’s gone from class AB to class D amps and been happy?*



K-pop sucks said:


> Just another way for manufacturers to cut corners and increase profit margins.


??? This doesn't even make sense.
There are cheap Class AB amps out there, and there are top quality ones.
There are cheap Class D amps out there, and there are top quality ones.
Class D doesn't equal cheap. Lack of build quality equals cheap.



K-pop sucks said:


> I'll stay true to class AB in my car and class H or AB at home.


Nothing wrong with this statement. Everyone has their preferences.


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## Redliner99 (Mar 26, 2018)

K-pop sucks said:


> I won't go class D anytime soon. Just another way for manufacturers to cut corners and increase profit margins. AB is superior to class D any day of the week.
> 
> I'll stay true to class AB in my car and class H or AB at home.




Your an idiot who doesn't believe in time delay anything you say is a wasted post on this fourm


Sent from my iPhone using Tapatalk


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## JCsAudio (Jun 16, 2014)

*Re: Who’s gone from class AB to class D amps and been happy?*

A quick google and read, seems like Class AB can have audible distortion in the lower octaves where human hearing is more sensitive and class AB can be susceptible to the power supply topping out under load. https://electronics.stackexchange.c...ss-ab-or-class-d-for-a-home-theater-amplifier

Read post #2, typical for sure.  https://www.avsforum.com/forum/90-r...4750-class-b-vs-class-d-amplifier-debate.html


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## Bayboy (Dec 29, 2010)

Pick a good designed amp in either or any class with whatever sonic quality you desire. Problem solved 

Sent from my SM-G955U using Tapatalk


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## K-pop sucks (May 28, 2018)

Redliner99 said:


> K-pop sucks said:
> 
> 
> > I won't go class D anytime soon. Just another way for manufacturers to cut corners and increase profit margins. AB is superior to class D any day of the week.
> ...


Believing in something and thinking something isn't necessarily are totally different things. I am using time delay currently and feel like it isn't honestly needed for the improvement. A well EQ'd system is more beneficial.


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## rc10mike (Mar 27, 2008)

When you get into high end audio, you enter this strange area. Some people swear up and down that their $500 or whatever power cable made a noticeable difference in SQ.

For car audio, I have always liked the way A/B sounded over D. Can I prove why in any measurable way? No.


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## preston (Dec 10, 2007)

In mountain biking we had a big debate on the proper wheel size with fierce devotion to 26", 27.5", and 29" wheels. One of the most famous memes came out of an article where it was declared the most important trait to being a mountain biker was to pick a wheel size, and then be a dick about it. 

So.....pick an amplifier topology, and then be a dick about it ha ha. 

(personally I"m in the camp of wondering if I could even tell the difference although I have never auditioned amps. But audio is part superstition sometimes, so I use big overpowered A/B amps for the front stage and big overpowered class D amps for the woofers and subs)


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## GEM592 (Jun 19, 2015)

*Re: Who’s gone from class AB to class D amps and been happy?*



preston said:


> In mountain biking we had a big debate on the proper wheel size with fierce devotion to 26", 27.5", and 29" wheels. One of the most famous memes came out of an article where it was declared the most important trait to being a mountain biker was to pick a wheel size, and then be a dick about it.
> 
> So.....pick an amplifier topology, and then be a dick about it ha ha.
> 
> (personally I"m in the camp of wondering if I could even tell the difference although I have never auditioned amps. But audio is part superstition sometimes, so I use big overpowered A/B amps for the front stage and big overpowered class D amps for the woofers and subs)


I ride a 26" even knowing that a 29" is the only size that makes sense, at least for me. So I am just hopeless.


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## rob feature (Nov 15, 2015)

*Re: Who’s gone from class AB to class D amps and been happy?*

Heh, I ride both but great analogy. Err, I should say I own both. I actually ride the 29ers - the 'new tech' that purists _still_ aren't so sure about. I'm pretty sure about them. Yeah, they're a smidge harder to get rolling & wheelbases tend to be a little longer, but angular momentum is greater. A larger wheel diameter means tackling larger obstacles with the same effort. Seems like the contact patch is larger too. But I know plenty of riders who refuse to ride them because purity. And refusal to believe that the larger wheels make a difference and aren't in some way a step down. I shouldn't complain - more for me right? Now about those electronic shifters


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## cmusic (Nov 16, 2006)

*Re: Who’s gone from class AB to class D amps and been happy?*

Amps have three sections: pre-amp, output, and power supply.

Pre-amp: Where the signal voltage is boosted or cut to match the output section to get the desired wattage. Signal processing like crossovers and eq can also be in the pre-amp section.

Output: This where the audio signal gets boosted with electrical current from the power supply section. 

Power supply: The section that supplies the electrical power to the rest of the amp.

The audio signature (how the amp sounds) comes mostly from the pre-amp first and followed by the output section. The power supply has nothing to do with the sound and yet at the same time a whole lot to do with the sound. If the power supply is built robustly enough to provide all the power the pre-amp and output sections need, then the type of power supply (A, A/B, D, ect..) does not matter. If you have two amps with the same pre-amp and output sections, but different power supplies, as long as the power supply section can provide all the electrical current needed, you will not hear a difference between the two amps. 

Now where people say class D amps sound different is in most class D amps are made to a smaller size. This smaller size limits the amount of electrical reserve the power supply has on tap. Namely the power supply section is made smaller in order to fit into a smaller chassis. 

Where I find small chassis class D amps, like the Alpine PDX, differs in sound to larger class A/B amps, like the Zapco LX amps, is that when the amp is pushed hard the small class Ds sound like they are running out of power while the larger class A/Bs have reserve power to get the sound reproduced correctly at the volume levels requested of it. Give the class D amps a power supply capability equal to the class A or A/B amps and I bet there will be no difference in the sound. 

It’s like taking two cars, say a base Honda Civic with 120 HP and a Ferrari with 800 HP. When driving both cars at 55 mph, both cars have enough power to do that. However if you want to do 175 mph, well we know which one has more than enough power to do that and which one doesn't. Class D amps that have a large enough power supply section in them (like the JL XDs) will be more equal to well-built class A and A/B amps.


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## Hillbilly SQ (Jan 26, 2007)

*Re: Who’s gone from class AB to class D amps and been happy?*



K-pop sucks said:


> Believing in something and thinking something isn't necessarily are totally different things. I am using time delay currently and feel like it isn't honestly needed for the improvement. A well EQ'd system is more beneficial.


You are entitled to your opinion but WOW. Ignorance at its finest.


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## Grinder (Dec 18, 2016)

*Re: Who’s gone from class AB to class D amps and been happy?*



preston said:


> In mountain biking we had a big debate on the proper wheel size with fierce devotion to 26", 27.5", and 29" wheels. One of the most famous memes came out of an article where it was declared the most important trait to being a mountain biker was to pick a wheel size, and then be a dick about it.
> 
> So.....pick an amplifier topology, and then be a dick about it ha ha.
> 
> (personally I"m in the camp of wondering if I could even tell the difference although I have never auditioned amps. But audio is part superstition sometimes, so I use big overpowered A/B amps for the front stage and big overpowered class D amps for the woofers and subs)


^Great analogy^

My '84 Cannondale (which I purchased new in '85) has 26" front and 24" rear. 

OP, sorry for the threadjack.


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## Hillbilly SQ (Jan 26, 2007)

Same analogy could be used for having the same truck but one with the base v6 engine and the other with the larger v8 engine. The v6 will get you around town and down the interstate fine but once you hook a trailer with any weight to it the insufficient v6 will let you know it's back there. The larger v8 will pull the load like it's not even back there more times than not. Then there's passing slowpokes on a 2-lane. My HEMI turning 3.21 gears (highway gears and 3.92 gears are for low end grunt) scared the **** out of me one morning passing a slowpoke on the 2-lane sucking in 22* air. Went from 45mph up to about 80mph in just a couple secondsAnd will try to pull the tongue off a trailer hauling 2000lbs. No way the Pentastar v6 would have been sufficient for my needs even though I considered one with that engine because they were practically giving them away brand new.


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## Truthunter (Jun 15, 2015)

*Re: Who’s gone from class AB to class D amps and been happy?*



cmusic said:


> Amps have three sections: pre-amp, output, and power supply.
> 
> Pre-amp: Where the signal voltage is boosted or cut to match the output section to get the desired wattage. Signal processing like crossovers and eq can also be in the pre-amp section.
> 
> ...


I've noticed watching online amp dynos what seems to be linked to what your talking about above:

Lots of newer smaller class d (and even some very popular around here class A/B) meet or slightly exceed thier rated continous power but clip not much further after that during the burst test - No "headroom". IMO - ok for meeting spec but not so great for music.

Compare this to some of the big old school class A/B which meet or exceed thier rated continuous power but will not clip until like 2x or more the rated power on the burst tests.

I've read on older threads, from around 2007-08 (after CEA-2006 came out), statements have been made that it is required to choose an amp rated at twice the rated power of the speaker for it to perform like the old amps.

And now I see a lot of more recent posts with statements like you need to use a 4ch amp bridged on midbass speakers for "headroom". I believe that's because these newer CEA-2006 amps don't have any built in headroom for those musical transients.


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## Hillbilly SQ (Jan 26, 2007)

*Re: Who’s gone from class AB to class D amps and been happy?*



Truthunter said:


> I've noticed watching online amp dynos what seems to be linked to what your talking about above:
> 
> Lots of newer smaller class d (and even some very popular around here class A/B) meet or slightly exceed thier rated continous power but clip not much further after that during the burst test - No "headroom". IMO - ok for meeting spec but not so great for music.
> 
> ...


Yeah I can see how this is the case. I've had amps that you could really tell the power supply was sagging. Mainly cheaper sub amps. Just like in mine and Chuck's auto analogies you can never have too much headroom.


----------



## Silvercoat (Dec 5, 2013)

*Re: Who’s gone from class AB to class D amps and been happy?*

For me the class D choice is always going to be size and power.

Taking up valuable trunk / interior space is hard for me.

I went with the Helix VEIGHT for my mids/highs and a JBL MS5001 for my sub.

This should sound just fine. I don't really feel like spending 3x as much will get me 3x the performance on sound quality.


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## gijoe (Mar 25, 2008)

*Re: Who’s gone from class AB to class D amps and been happy?*



cmusic said:


> Amps have three sections: pre-amp, output, and power supply.
> 
> Pre-amp: Where the signal voltage is boosted or cut to match the output section to get the desired wattage. Signal processing like crossovers and eq can also be in the pre-amp section.
> 
> ...


I like this post, and agree with most everything, but I'm curious about one thing. 

" when the amp is pushed hard the small class Ds sound like they are running out of power"

What does an amp that's running out of power sound like? 

Would you be able to pick out a well built, low powered class D amp that is being pushed near the limits of it's power supply over a higher powered class D amp that is more comfortably within the limits of it's power supply? Maybe you could tell the difference in a double blind test, but I doubt it. We aren't talking about clipping an amp, which isn't too difficult to hear, we're talking about an amp that is running out of power, and I don't know what that sounds like. 

People often claim to hear a difference, because their research, a product's specs, and anecdotal claims from their peers tell them that there should be a difference. Do all amps sound exactly the same? No. But in a double blind test, could you pick out a good AB amp nearing the limits of it's power supply, compared to a good D amp nearing the limits of it's power supply, compared to an AB amp comfortably within the limits of it's power supply, compared to a D amp comfortably within the limits of it's power supply? I highly doubt it.


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## K-pop sucks (May 28, 2018)

I don't get the argument for space constraints. Just put the amp under your seat or rear cargo cover as usual. Same goes for power, if you're that energy conscious you probably shouldn't be driving a car and take the bus. If you've got a seat or spare tire, you have plenty of space for an amp or amps.


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## Bayboy (Dec 29, 2010)

Sure, screw aesthetics & stealth regardless of the limitations in real estate. Just buy some beefy surfboard amps and throw them ****s in there even if passengers wind up kicking them to death, or groceries melt from sitting on top of a stove top heatsink. Get them ****s in there, yo!

Sent from my SM-G955U using Tapatalk


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## Redliner99 (Mar 26, 2018)

Bayboy said:


> Sure, screw aesthetics & stealth regardless of the limitations in real estate. Just buy some beefy surfboard amps and throw them ****s in there even if passengers wind up kicking them to death, or groceries melt from sitting on top of a stove top heatsink. Get them ****s in there, yo!
> 
> Sent from my SM-G955U using Tapatalk




K pops an idiot I hope no one takes anything he says with any seriousness 


Sent from my iPhone using Tapatalk


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## Hillbilly SQ (Jan 26, 2007)

*Re: Who’s gone from class AB to class D amps and been happy?*



Bayboy said:


> Sure, screw aesthetics & stealth regardless of the limitations in real estate. Just buy some beefy surfboard amps and throw them ****s in there even if passengers wind up kicking them to death, or groceries melt from sitting on top of a stove top heatsink. Get them ****s in there, yo!
> 
> Sent from my SM-G955U using Tapatalk


And I cringe when I see someone get rid of their spare tire to put car audio stuff in its place. Their choice but one day their time will come when their tire is ruined where fix-a-flat and/or a plug kit and an air compressor won't do them any good. AND they don't have cell phone service. And they're in deliveranceville. YOU GOT A REAL PRETTY MOUTH BOY!


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## preston (Dec 10, 2007)

*Re: Who’s gone from class AB to class D amps and been happy?*



cmusic said:


> Amps have three sections: pre-amp, output, and power supply.
> 
> Pre-amp: Where the signal voltage is boosted or cut to match the output section to get the desired wattage. Signal processing like crossovers and eq can also be in the pre-amp section.
> 
> ...


I'm not an expert on amplifier topology, but isn't the output section of a class D significantly different from A/B ? From what I remember the class D is sort of switching the voltage rails at high frequency, I'm not sure if they still have a positive and negative transistor or not. I realize I could go back and read the literature but I'm just saying I think the output sections are significantly different so surely that has the potential to color the sound ?


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## cmusic (Nov 16, 2006)

*Re: Who’s gone from class AB to class D amps and been happy?*



gijoe said:


> I like this post, and agree with most everything, but I'm curious about one thing.
> 
> " when the amp is pushed hard the small class Ds sound like they are running out of power"
> 
> ...


Great question! Hopefully I can explain it here.

In my previous car I first had an Alpine PDX F6 (150x4) and then a Zapco Z-150.6 LX on the same Scanspeak mids and tweeters. Both amps are rated at 150 watts per channel. The Alpine is a small class D about 1/3 the size of the Zapco. The Alpine sounded clean and just as good as the Zapco when listening to music at low to moderate levels or with music that does not have a lot of transients in them. (Transients in music is where the music changes in volume quickly, like a kick drum being kicked or in case of Tchaikovsky's 1812 Overture canons being fired.) 

But when I cranked up the volume or a loud transient hit, the Alpine just seemed to go "blah" as compared to the Zapco. Musician David Benoit has an acoustical song called "Beach Trails" that I use to test amps for transient response. The song starts out at a low level for the first 10-15 seconds with a smooth relaxing synthesizer playing. Then a huge transient of brass horns and other instruments instantly comes on and is similar to a cannon going off behind you when you don't know it and it scares the sh*t out of you. I've listened to this track perhaps thousands of times and know exactly when the transient hits. With the Alpine I only heard the sound of the transient, but it did not scare me. The transient was not at a realistically loud level and even sounded a little distorted. The Zapco that replaced the Alpine never had that problem.

Simply put, the amp did not have enough reserve power to correctly reproduce the sound at a loud level. This is due to the Alpine amp's small size not being able to have enough internal capacitors and other parts to have a reserve of electrical power when the music needed it. Again, at low and medium volumes, the amp sounded really great, and would meet the needs of 99% of the people that would use it.

Now I have heard from some people that if I put a line driver before the Alpine to boost the RCA voltage and put a battery or large capacitor near the amp, that would solve the transient problem. Doing those two things may help or eliminate the lack of power but its like having to add an aftermarket turbo to your car's engine to boost HP when you could have simply bought a different car with a more powerful engine in the first place.

At the 2017 MECA/IASCA finals Mike Young and I got into his white WV Bug (that won the MECA Extreme class that year) and listened to the same "Beach Trails" song. As I started the track I told Mike to crank up the volume. When the transient hit, he jumped up almost out of the driver's seat and hit his head on the car's roof and door. The dynamics of the transient startled him so much he had a huge physical reaction to the music! Mike was using Revelation Audio amps that were built with a HUGE power supply section (I think it was class G, which is sort of a hybrid of A/B and D.). We replayed the song and Mike jumped again, even while knowing the transient was coming. That was a sign of an amp that could produce music exactly as it is supposed to be at any volume level. 

As far as double blind tests, when amps are playing within their limits and have a similar acoustical output, it is very very very difficult to hear the differences. When the amps are driven to their limits, I do believe differences can be heard even in a double blind test.

Hope this helps


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## cmusic (Nov 16, 2006)

*Re: Who’s gone from class AB to class D amps and been happy?*



preston said:


> I'm not an expert on amplifier topology, but isn't the output section of a class D significantly different from A/B ? From what I remember the class D is sort of switching the voltage rails at high frequency, I'm not sure if they still have a positive and negative transistor or not. I realize I could go back and read the literature but I'm just saying I think the output sections are significantly different so surely that has the potential to color the sound ?


Yes, the classes are very different. Here are some sites that explain the differences in detail:
https://www.audioholics.com/audio-amplifier/amplifier-classes
https://www.electronics-tutorials.ws/amplifier/amplifier-classes.html
https://www.bhphotovideo.com/explora/audio/tips-and-solutions/amplifier-classes-explained

Simply put an amplifier amplifies the audio signal (actaully a sine-wave) in two parts, the wave above 0 (or the positive part as you put it) and the negative part below 0 (again, as you put it).

A very simple explination:
Class A means both sides of the audio sine-wave has power.
Class B means the side that sine-wave is in if fully powered while the other side that is not being amplified at the moment is partially powered.
Class D means only the side that is being played at the moment is powered and the other side is fully turned off.

When the power switches sides in the audio signal, a little bit of noise is made. That noise is called switching noise. Since the power is on for both sides at all times, Class A amps generally has little to no switching noise. Class B and A/B amp's swithcing noise to generally so light, it is not heard. Old Class D amps had switching noise so bad, that it could be easily heard. That's why most old Class D amps were limited to bass frequencies under 200Hz, where the switching noise (usually around 2KHz) was masked by the bass. In today's class D designs the switching noise has been moved to above 22 KHz and technically out of the range of human hearing.


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## gijoe (Mar 25, 2008)

*Re: Who’s gone from class AB to class D amps and been happy?*



cmusic said:


> When the amps are driven to their limits, I do believe differences can be heard even in a double blind test.


And, I would probably agree (amps do clip differently), BUT are the differences enough so that we can say AB is better, or can we come to the conclusion that a more robust amp, regardless of topology, would perform better? It sounds like this is not a debate about topology (AB vs. D), but more an argument in favor of "headroom." I read your comments as saying 'the bigger amp wins'. Having the power available to accurately reproduce the dynamics makes sense (although I do thing this one is highly exaggerated and misunderstood by most people) regardless of the topology. 

Thoughts?


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## Patriot83 (May 10, 2017)

*Re: Who’s gone from class AB to class D amps and been happy?*

So what has Rockford created with their class AD amps? Not much info out there about this "proprietary" technology. Their site just says class A fidelity with increased efficiency and power.


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## cmusic (Nov 16, 2006)

*Re: Who’s gone from class AB to class D amps and been happy?*



gijoe said:


> And, I would probably agree (amps do clip differently), BUT are the differences enough so that we can say AB is better, or can we come to the conclusion that a more robust amp, regardless of topology, would perform better? It sounds like this is not a debate about topology (AB vs. D), but more an argument in favor of "headroom." I read your comments as saying 'the bigger amp wins'. Having the power available to accurately reproduce the dynamics makes sense (although I do thing this one is highly exaggerated and misunderstood by most people) regardless of the topology.
> 
> Thoughts?


In general I would go with the more powerful amp, given the output frequency response is the same. However that does not mean I would take the more powerful amp every time. Given my choice between an 30x2 Milbert class A tube amp and a well designed and built 200x2 full range class D to power my tweeters and mids, I would choose the Milbert.

However I will go back to by post on page 4 that the pre-amp and output section of the amp has more to do with the sound than the power supply does, given the power supply can provide enough power as needed. 

And one had to take in account the size and price point the amp's manufacture is aiming for. Every amp designer wants to make the best amp they can, but when the bosses above needs to make an amp a certain size and to match a certain budget, things have to be changed to meet those goals. Those provisions to meet the selling goals can affect the sound of the amp.


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## JCsAudio (Jun 16, 2014)

*Re: Who’s gone from class AB to class D amps and been happy?*

I'm just curious and capitalizing on what gijoe has stated and the other well thought out statements within this thread. Since the topic has moved to the discussion of headroom and power supplies I was wondering if someone had the ability to actually measure the transient peaks on music with a dynamometer for an amplifier? It seems like a simple way to verify this but of course it also requires an investment in that equipment. Someone reading this thread might have access to it. Even though I do not disagree with these seemingly valid points they do seem to be somewhat anecdotal in nature. 

Taking into account what Andy Wehmeyer has written in his article about the actual theoretical power needed when playing music and being frequency dependent; I wonder then why a 150 wpc amplifier like an Alpine PDX F6 would run out of dynamic power playing music on tweeters like cmusic has stated? Maybe it was just the midrange speakers that were starving of power and midrange speakers play frequencies in the area where human hearing is most sensitive. 

https://www.audiofrog.com/community...se-and-why-your-tweeters-never-get-150-watts/


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## gijoe (Mar 25, 2008)

*Re: Who’s gone from class AB to class D amps and been happy?*



V8toilet said:


> Taking into account what Andy Wehmeyer has written in his article about the actual theoretical power needed when playing music and being frequency dependent; I wonder then why a 150 wpc amplifier like an Alpine PDX F6 would run out of dynamic power playing music on tweeters like cmusic has stated?
> 
> https://www.audiofrog.com/community...se-and-why-your-tweeters-never-get-150-watts/


I don't believe the amp would run out of dynamic headroom, and I don't believe most people experience any amp running out of dynamic headroom during typical listening (not just with tweeters). I think the importance of headroom has been drastically misunderstood and exaggerated (as I've mentioned). But, I am curious to participate in a proper test to see if I can hear the difference. It's easier to starve an amp using low frequencies, so I'd love to compare dynamics at around 80 hz (since you'd typically have a dedicated sub amp to handle everything below that) between an 50 watt per channel amp, and a 100 watt per channel amp, or 2 amps rated with the same power output, but with different power supplies. I'd bet that in a proper scientific test most people couldn't hear any difference with music (maybe they could with tones). I'm always happy to be proven wrong.


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## JCsAudio (Jun 16, 2014)

*Re: Who’s gone from class AB to class D amps and been happy?*



gijoe said:


> I don't believe the amp would run out of dynamic headroom, and I don't believe most people experience any amp running out of dynamic headroom during typical listening (not just with tweeters). I think the importance of headroom has been drastically misunderstood and exaggerated (as I've mentioned). But, I am curious to participate in a proper test to see if I can hear the difference. It's easier to starve an amp using low frequencies, so I'd love to compare dynamics at around 80 hz (since you'd typically have a dedicated sub amp to handle everything below that) between an 50 watt per channel amp, and a 100 watt per channel amp, or 2 amps rated with the same power output, but with different power supplies. I'd bet that in a proper scientific test most people couldn't hear any difference with music (maybe they could with tones). I'm always happy to be proven wrong.


If Andy is right than I don't think its even possible with tweeters even with 50 wpc RMS. With a midwoofer, well that might be possible even with 150 wpc.


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## rob feature (Nov 15, 2015)

*Re: Who’s gone from class AB to class D amps and been happy?*



V8toilet said:


> ...I was wondering if someone had the ability to actually measure the transient peaks on music with a dynamometer for an amplifier? It seems like a simple way to verify this but of course it also requires an investment in that equipment. Someone reading this thread might have access to it.


Big D Wiz does this sorta stuff. Not sure if he's ever tried to do such a comparison, but he has the gear and definitely has the old school amp collection. Watching a few of those videos and making a spreadsheet with the data might make for some interesting results.


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## JCsAudio (Jun 16, 2014)

*Re: Who’s gone from class AB to class D amps and been happy?*



rob feature said:


> Big D Wiz does this sorta stuff. Not sure if he's ever tried to do such a comparison, but he has the gear and definitely has the old school amp collection. Watching a few of those videos and making a spreadsheet with the results might make for some interesting results. Could turn into a weekend project?


I almost mentioned him. Sounds like a good YouTube video for him to conjure up. It might reveal the hidden truth about the difference between cheap amplifiers that meet the CEA rating and high quality amplifiers with robust power supplies that make the same power with test tones but kill it dynamically. Might be good to have a standard test playing the same song with good dynamics for every amplifier to compare them to each other.


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## Bnlcmbcar (Aug 23, 2016)

*Re: Who’s gone from class AB to class D amps and been happy?*

In the end I opt for a middle ground. Tube preamps with Class D amps 

Even people who have switched from A/B to D can’t truly tell you unless they underwent a true unbiased, same setup, no delay between switches comparison.

Lack of knowledge and transparency has been a major factor impeding Class D from overcoming the stigma of its early implementations. Class D topology is significantly harder to build and engineer to audiophile standards than it is with the Class A/B topology.

Inherently this means there are much fewer people in the world with the knowledge about engineering class D audio amplifiers from the ground up for audio SQ purposes.

So that translates to even fewer car amplifier companies that are actually designing their own class D amp topologies versus implementing run-offs of reference designs/layouts.

Example:

Open up an MMATS Hifi series amp. Then google:
“iraudamp4”

You'll find that the MMATS HiFi is pretty much an exact copy of the amplifier outputs (minus the pre-amps). From the integrator to outputs and most of the power supply house-keeping is more or less identical. So MMATS Class D is designed off a reference design from Infineon Technologies.

http://www.irf.com/technical-info/refdesigns/iraudamp4.pdf

This revelation came to me from another fellow DIYMA member who is a well regarded, intelligent, and a trusted member that repairs Class D amps himself. MMATS did not disclose this information to me. Most companies will not reveal true details about their Class D implementations. Once again due to lack of the actual knowledge or lack of being transparent.

As mentioned earlier there are very few true Class D architects out there that understand the topology enough to design an amp from the ground up to meet audiophile standards.

Bruno Putzey is one of those few people. He is responsible for UcD which is a technology for Class D (among others). He actually developed the tech himself while working at Phillips. He later took that development and partnered with people to start Hypex which is a company that currently sells amps based on the UcD technology (as well as an updated version by the name of NCore).

Google “Hypex Class D” and you’ll find they are highly praised throughout the home audio scene by both DIY’ers and boutique High End Amp makers that use the Hypex Modules in their expensive amplifiers. Many prefer them over the Bang & Olufsen ICEpower designs.

Hypex Class D is utilized in ultrahigh-fidelity systems for studio and home use, providing flat frequency response irrespective of load impedance, nearly frequency independent distortion behaviour and very low radiated and conducted EMI. Control is based on a phase shift controlled self-oscillating loop taking feedback only at the speaker output.

Hypex UcD is the only one able to openly claim/publish low, flat THD response, invariant of frequency and load. This allows for very linear power with a frequency response that is almost load invariant.

So that lift in the top octaves that creates the unwanted “too cold” sound found in poor or older class-D topologies has been in theory ‘solved’ with UcD. Their amplifier topology remains linear through the entire range regardless of load impedance. It is just "neutral" what goes in is what comes out, clear and clean.

If you really want to dive in check out the Hypex white paper:

https://www.hypex.nl/img/upload/doc/an_wp/WP_AES118BP_Simple_self-oscillating_class%20D_amplifier.pdf

The secret sauce seems to be in the patented post-filter feedback design.

Yes... I’m doing all this raving about Hypex Class D. That is because I can due their transparency both literally and sonically.

Question is who actually uses Hypex UcD amplification in our 12v automotive industry?

So far Biketronics is the only one I have found. 
The motorcycle amp company!? Yep. But at 180 watts a channel @ audiophile specs, made in the USA with lifetime warranty.. it’s hard to beat in regards to Class D (I have used JL HD, JL XDv2, and MMATS Hifi).

JL has their own tech with Single Cycle control in the HD series and NexD in the XD and VXi. Single Cycle Control I think they licensed from outside party hence the price tag. NexD is their own proprietary baby but good luck finding any details about what NexD is actually comprised of and how it differs from other techs.

*A little more info about Bruno from Sound and Vision:

S&V: Generally speaking, what are the key benefits of Class D versus the traditional Class AB and Class A designs that have long been favored by audiophiles? 

BP: Efficiency and therefore the ability to construct amps that are powerful for their size. Only that. Modern Class D amps, in particular mine—ahem—sound good not because they’re Class D, but in spite of it. I can’t repeat that often enough. Left to its own devices, a switching power stage tries to do just about anything except amplify audio. You choose Class D to save energy but it’s all elbow grease after that. People don’t realize how much more challenging Class D is compared to Class AB. It’s truly an order of magnitude.

https://www.soundandvision.com/content/bruno-putzeys-head-class-d#AIQPKcJQwFsL2Zkd.99


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## TaylorMade (Feb 11, 2017)

Bnlcmbcar said:


> In the end I opt for a middle ground. Tube preamps with Class D amps <img src="http://www.diymobileaudio.com/forum/images/smilies/smile.gif" border="0" alt="" title="Smile" class="inlineimg" />
> 
> Even people who have switched from A/B to D can’t truly tell you unless they underwent a true unbiased, same setup, no delay between switches comparison.
> 
> ...


Incredibly well said bnlcmbcar, and very informative. Makes me want to get my BT6180 and BT4250 even more now.
Also, I agree with the statements about “blind tests” normally when you hear about someone doing an A/B comparison there is significant time in between tests. I feel the longer that time is, the less you “hold” in your mind about the previous test. If you can’t switch back and forth immediately, I feel you will not get the full picture


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## PPI_GUY (Dec 20, 2007)

*Re: Who’s gone from class AB to class D amps and been happy?*



Bnlcmbcar said:


> In the end I opt for a middle ground. Tube preamps with Class D amps
> 
> Even people who have switched from A/B to D can’t truly tell you unless they underwent a true unbiased, same setup, no delay between switches comparison.
> 
> ...


Very, very interesting. Thank you for that. 
To continue down this path, I think I have also seen "Hypex" mentioned with the development of Gan-FET technology for ultra high fidelity class D sound reproduction. The articles I have read promise that Gallium Nitrade based fets will allow higher switching speeds than currently possible resulting in very low THD, more efficiency and even less heat generation than current class D. This is promised as the next step for class D that when fully realized will be equal to or possibly even surpass class A in audio reproduction quality. So far I think only SoundDigital has used Gan-FET technology in a mobile audio amplifier but, with pretty stunning results. 
What do you know about the status of this technology that will greatly enhanced class D?


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## HardCoreDore (Apr 30, 2014)

*Re: Who’s gone from class AB to class D amps and been happy?*



bluesman1 said:


> This is an interesting discussion because I don't think there were any full range class D amps out yet when I bought my last amp. I'm still running a JL 500/5 from 2002. It's got a class D sub section. I remember that these JL's were panned by some folks shortly after they came out. It replaced my US Amps when I downsized the system. There were definitely some sonic changes but the power level was way down and there were some other system changes made at the same time. Never thought the JL sounded bad though and I can't complain because I haven't had a single issue with the amp.
> 
> 
> 
> Way back when I had been through Kenwood, Orion, Autotek, US AMPS and a couple others for amplification. It's been so long now that I don't have a point of reference aside from that 17 year old JL amp. Last system I put in from scratch was in my son's old Nissan maybe 8 years ago. That was a 4 channel A/B Alpine. I don't think I've even heard a class D amp in a car, other than on subs.


The slash amps are great class A/B Amps! You'd better hope nothing ever goes wrong with it. Mine blew up, & it's the only Slash Series that JL won't fix under their "Repair Program". I was super pissed! I absolutely ADORED that amp! Sounded amazing! 

Edit: Good luck trying to fix it yourself too... TONS of SMDs & a SUPER-TIGHT BOARD that would be a nightmare to work on. That's what's so great about their Repair Program. They just pop in a new board & mail it back for a discounted price... FML! 

Sent from my SM-G950U using Tapatalk


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## bluesman1 (Mar 2, 2010)

*Re: Who’s gone from class AB to class D amps and been happy?*



HardCoreDore said:


> The slash amps are great class A/B Amps! You'd better hope nothing ever goes wrong with it. Mine blew up, & it's the only Slash Series that JL won't fix under their "Repair Program". I was super pissed! I absolutely ADORED that amp! Sounded amazing!
> 
> Sent from my SM-G950U using Tapatalk


If it dies and I can't fix it myself, I won't have any complaints. I've gotten 17 years out of it so far.


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## Truthunter (Jun 15, 2015)

*Re: Who’s gone from class AB to class D amps and been happy?*



rob feature said:


> Big D Wiz does this sorta stuff. Not sure if he's ever tried to do such a comparison, but he has the gear and definitely has the old school amp collection. Watching a few of those videos and making a spreadsheet with the data might make for some interesting results.


BigDWiz (Williston Audio Labs) is one of youtube channels I was refering too in my post. There are few others also but that one seems to be the most popular. Most of tests are for monoblock basshead amps but there are some 2 & 4 channels mixed in there also. I haven't made a spreadsheet but have come to realize some amps I'll likely stay away from if I ever decide to swap out my current amps.


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## Hillbilly SQ (Jan 26, 2007)

The Biketronics amps have been on my radar for a while now. I'm sure if one of them ever ended up in my truck it would be the last amp I buy for a really long time making the price well worth it.


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## Zippy (Jul 21, 2013)

*Re: Who’s gone from class AB to class D amps and been happy?*



Hillbilly SQ said:


> Bo, what kinda scratch do those BeWith amps cost? Being Japanese I'm sure they're built to sound as good as possible and last as long as possible.




They were quite pricey, MSRP of around $9k for the 6 of them. I did get a deal on them cause a newer model was coming out shortly after I bought them. I’ll be at the NC get together with my BRZ if anyone wants to hear them.


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## Hillbilly SQ (Jan 26, 2007)

*Re: Who’s gone from class AB to class D amps and been happy?*



Zippy said:


> They were quite pricey, MSRP of around $9k for the 6 of them. I did get a deal on them cause a newer model was coming out shortly after I bought them. I’ll be at the NC get together with my BRZ if anyone wants to hear them.


Whew I'm sure they're top notch but too rich for my blood


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## Hillbilly SQ (Jan 26, 2007)

*Re: Who’s gone from class AB to class D amps and been happy?*

So, looking at the Bikitronics amps it appears they come with some accessories for bike hookup but probably won't be needed in a car environment. How much for just the amp? And can a pair of channels be bridged to a sub? I'm entertaining the idea of using one or two of them at some point but JL already makes a fine sounding class D and also waiting for the Zapco ST dsp 6ch to come out to see if the dsp in it is worth having. The 65x4 I have going to my mids and tweets will already run me out of there if I let it.


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## ErinH (Feb 14, 2007)

*Re: Who’s gone from class AB to class D amps and been happy?*



Truthunter said:


> BigDWiz (Williston Audio Labs) is one of youtube channels I was refering too in my post. There are few others also but that one seems to be the most popular. Most of tests are for monoblock basshead amps but there are some 2 & 4 channels mixed in there also. I haven't made a spreadsheet but have come to realize some amps I'll likely stay away from if I ever decide to swap out my current amps.


Funny you mention this... 

I actually have been considering resuscitating my medleysmusings site and focusing my efforts on electronics testing. I mentioned this to the guys (Steve W, Jason B, Scott and Bill) yesterday in a group message. It's been something I've wanted to do for over 10 years; I used to test headunits using RMAA back in the day and I posted the results on this site. I quit doing it, though, because RMAA is capabilities-limited and really a PITA outside of basic tests. 

I'd like to get in to testing headunits, DSPs and amplifiers and post the data on my site. The issue, however, is finding accurate measurement equipment that doesn't cost an arm and a leg. Trust me, I've looked. I've talked to people who do it for a living and there's only one option that I could even get close to affording and that is >$500 (the really good stuff is $5k+ _used_). I think the only way I could get something like this off the ground is by starting a crowd funding campaign; gofundme or the like. Otherwise, I just can't afford the measurement gear to *accurately and reliably* measure the kind of things I want.


----------



## Bnlcmbcar (Aug 23, 2016)

PPI_GUY said:


> Very, very interesting. Thank you for that.
> To continue down this path, I think I have also seen "Hypex" mentioned with the development of Gan-FET technology for ultra high fidelity class D sound reproduction. The articles I have read promise that Gallium Nitrade based fets will allow higher switching speeds than currently possible resulting in very low THD, more efficiency and even less heat generation than current class D. This is promised as the next step for class D that when fully realized will be equal to or possibly even surpass class A in audio reproduction quality. So far I think only SoundDigital has used Gan-FET technology in a mobile audio amplifier but, with pretty stunning results.
> What do you know about the status of this technology that will greatly enhanced class D?


Seems like Gan-FET is the logical next step for any class D tech. Class-D amplifier takes an analogue audio input signal and from this generates the PWM signal to be amplified. 

There are many sources of error in the output stage leading to an amplified PWM signal that is far from ideal. Sources of error, as shown in attached pic, include power supply ripple, voltage drops from the switching devices (typically MOSFETs, and sometimes Direct FET), overshoot and undershoot, rise and fall times and turn on and turn off delays. Each of these unwanted artifacts is a source of THD in the resulting output audio signal. (See attached pic).

Current Class D designs have been trying to address these physical limitations of Mos-FET and Direct FET with negative feedback filter schemes to act as corrective measures. Hence why the different Class D techs and schools of thought on how to implement that corrective feedback fitter exist.

Gan-FET is a game changer because it delivers a more accurate power replication of the small signal PWM. (See Attached pic). So with less sources of error in the output stage to begin with there wil be lower amounts of correction needed to be implemented by feedback control.

Class D first showed up in the 1960’s. It was decades later until it showed up in mobile applications. Gan-FET didn’t come fruition until this last decade. I was stoked to see a company like SoundDigital to already be incorporating the tech in amplifiers. But sighs it was only a limited run.

I read an article in Mobile Electronics magazine that SoundDigital (Brazilian company) is on the mission to ramp up their business operations to become a bigger player in the USA. I’m hoping the limited run might be a proof of concept for a line they launch (hopefully soon) with their US venture.



Hillbilly SQ said:


> So, looking at the Bikitronics amps it appears they come with some accessories for bike hookup but probably won't be needed in a car environment. How much for just the amp? And can a pair of channels be bridged to a sub? I'm entertaining the idea of using one or two of them at some point but JL already makes a fine sounding class D and also waiting for the Zapco ST dsp 6ch to come out to see if the dsp in it is worth having. The 65x4 I have going to my mids and tweets will already run me out of there if I let it.


Official prices:

BT2180 - $450
BT4180 - $650
BT4250 - $900
BT6180 - have to call in

*But call in. They sometimes are willing to take 10% off. Also if your able to reach Mike.. the last time I spoke to him in November he said they were working on a Car Specific project. Didn’t disclose details but he might have some more now.

Unfortunately no bridging to my knowledge. They may be able to make a monoblock for you though. Larger Hypex modules come in 400w and 700w versions then a giant 2k w version. 

I repurposed my MMATS HiFi 4250 from mid-bass to subwoofer duty and going Biketronics BT4250 for mid-bass.


----------



## preston (Dec 10, 2007)

It just seems like there is so much more going on in a class D. As you said much more complex to build and design right. In a world where people care what types of caps are used on the circuit board (not to mention their "interconnects" ie RCA cables) it would be silly not to think that class D and class AB could have very different sonic signatures depending on implementation. That doesn't answer if one is superior to the other, but I've always personally subscribed to the audio simple path philosophy, and so my audio superstition is that a class A or class AB has an overall cleaner, simpler signal path. Which is why I still stick to AB on the mids and highs. But then again I run circa 2000 Rockford Fosgate amps so I may not even know what an SQ mobile amp sounds like. But I do remember thinking it would be cool to run two small class D amps as "mono blocks" instead of the RF amp I had in there, and I changed everything all around and I remember thinking at the time "Hmm, I don't think it sounds as good" but it was too late to go back at that point and it was in an older truck so I wasn't that motivated.


----------



## GreatLaBroski (Jan 20, 2018)

*Re: Who’s gone from class AB to class D amps and been happy?*



ErinH said:


> Funny you mention this...
> 
> I actually have been considering resuscitating my medleysmusings site and focusing my efforts on electronics testing. I mentioned this to the guys (Steve W, Jason B, Scott and Bill) yesterday in a group message. It's been something I've wanted to do for over 10 years; I used to test headunits using RMAA back in the day and I posted the results on this site. I quit doing it, though, because RMAA is capabilities-limited and really a PITA outside of basic tests.
> 
> I'd like to get in to testing headunits, DSPs and amplifiers and post the data on my site. The issue, however, is finding accurate measurement equipment that doesn't cost an arm and a leg. Trust me, I've looked. I've talked to people who do it for a living and there's only one option that I could even get close to affording and that is >$500. I think the only way I could get something like this off the ground is by starting a crowd funding campaign; gofundme or the like. Otherwise, I just can't afford the measurement gear to *accurately and reliably* measure the kind of things I want.


I know you've been on podcasts, but it's possible you can really make a dent by bringing these tests to Youtube. If you decide to do it.

Wiliston Audio Labs (BigD Wiz) has some videos breaking 1mm views. That is a couple thousand dollars in ad revenue each if he monetizes them. This could be something that can become self sustaining at some point in the future. I think there's a real hole in the market for people who do testing that goes beyond simple amplifier dyno testing. Harmonics testing, IMD testing, etc could be really good.

I'd love to see it happen.


----------



## Hillbilly SQ (Jan 26, 2007)

*Re: Who’s gone from class AB to class D amps and been happy?*



GreatLaBroski said:


> I know you've been on podcasts, but it's possible you can really make a dent by bringing these tests to Youtube. If you decide to do it.
> 
> Wiliston Audio Labs (BigD Wiz) has some videos breaking 1mm views. That is a couple thousand dollars in ad revenue each if he monetizes them. This could be something that can become self sustaining at some point in the future. I think there's a real hole in the market for people who do testing that goes beyond simple amplifier dyno testing. Harmonics testing, IMD testing, etc could be really good.
> 
> I'd love to see it happen.


I agree. And I'm willing to bet if a go fund me account was opened for the cause lots of people would be willing to help get things going. And Erin's personality could be a big help on the videos too.


----------



## High Resolution Audio (Sep 12, 2014)

*Re: Who’s gone from class AB to class D amps and been happy?*

For what it's worth, I run Class A Biased amplifiers on my Tweeters and Midrange and Class AB on the Woofers and Subwoofers. 

I happen to be one of those people that can hear subtle differences. I competed in the 2018 Season and sat in a lot of SQ vehicles. 

I sometimes could tell the amp topology without knowing anything about a system. 

I've always run 2 or 3 times the rated power for dynamics and transient responses. 

But, for me, the differences are what happens in between the notes. Class A or AB carry longer and take longer to decay. Little details become more apparent, and Echos and recording room reverberations can be more easily distinguished. There is less silence between notes. 

Also, the sound stage changes from two dimensional to three dimensional. Depth and Width increases. 

I attribute these differences simply to less distortion and more precise control of driver movement. 

For me, A biased AB amps sound more musical ( instruments sound more like instruments a vocals sound more like a human singing ).

With that being said, some vehicles that were technically brilliant and scored really high at competitions for me didn't sound real and lifelike to me. Yet they scored really high. I found some of them to image really well and have razor-like focus.

It comes down to the believability for me. 

With that being said, JBL makes some class D amps that are getting closer and closer to AB believability. Technology is getting better for sure.


----------



## Mullings (Jan 31, 2016)

How did the Prius sound?


----------



## dcfis (Sep 9, 2016)

High Resolution Audio said:


> For what it's worth, I run Class A Biased amplifiers on my Tweeters and Midrange and Class AB on the Woofers and Subwoofers.
> 
> I happen to be one of those people that can hear subtle differences. I competed in the 2018 Season and sat in a lot of SQ vehicles.
> 
> ...


Which jbls?


----------



## gijoe (Mar 25, 2008)

*Re: Who’s gone from class AB to class D amps and been happy?*



High Resolution Audio said:


> I sometimes could tell the amp topology without knowing anything about a system.


You could "sometimes" tell, meaning that you couldn't always tell. Sometimes you were right, and sometimes you were wrong. Not to be a jerk, but anyone can guess right sometimes, unless you can hear a difference conclusively, and repeatable, your experience shows nothing more than a guess that happened to be correct.


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## Hillbilly SQ (Jan 26, 2007)

*Re: Who’s gone from class AB to class D amps and been happy?*



gijoe said:


> You could "sometimes" tell, meaning that you couldn't always tell. Sometimes you were right, and sometimes you were wrong. Not to be a jerk, but anyone can guess right sometimes, unless you can hear a difference conclusively, and repeatable, your experience shows nothing more than a guess that happened to be correct.


Yeah and the tune could play a big part in it too. I'll admit I do like the sound of an a/b amp most of the time but that's just because it seems to be a lot easier to mess up the design of a class D if the engineer isn't on top of things. This is why I think it's wise to stick with known good d amps such as the JL RD and XD, Biketronics, and apparently the Mmatts Hifi amps. PDX and the board used in the NVX JAD and older Phantom and TN amps (and a Hertz amps I think?) seems to all be proven too.


----------



## rob3980 (Jun 11, 2010)

I talked to Steve cook today and he recommended the helix p six and p2. Said they are excellent


----------



## Hillbilly SQ (Jan 26, 2007)

*Re: Who’s gone from class AB to class D amps and been happy?*



rob3980 said:


> I talked to Steve cook today and he recommended the helix p six and p2. Said they are excellent


Heard that exact amp combo running a high end Morel 3-way set and JL 10w3v3 10 back in November and it was incredible. Woulda never known the amps were class D. Actually, Cook did the install on this car.


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## Babs (Jul 6, 2007)

rob3980 said:


> I talked to Steve cook today and he recommended the helix p six and p2. Said they are excellent



The P Six P2 combo looks like it would be an awesome 2-box simple but great setup. 


Sent from my iPhone using Tapatalk Pro


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## rob3980 (Jun 11, 2010)

Babs said:


> rob3980 said:
> 
> 
> > I talked to Steve cook today and he recommended the helix p six and p2. Said they are excellent
> ...


In my case i would have to go 2 Psix and a P2 . I’m going to give these MMATS a go and if not I’ll make the switch


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## truckguy (Sep 2, 2013)

*Re: Who’s gone from class AB to class D amps and been happy?*



rob3980 said:


> I talked to Steve cook today and he recommended the helix p six and p2. Said they are excellent


This is what I recommended earlier! Not the P2 but the P6. I’m making a road trip to Audio X next week! It’s just crappy class d though.


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## B5I8 (Feb 7, 2009)

I installed my (2) HiFi-4250D’s and (1) HD4000.1 two days ago. They are tremendous amps. My Phoenix Gold Ti2’s they replaced were okay but having so much more power on tap really brings my system to life. Very very dynamic, huge in every way except for physical size. Going from 1600W on my pair of Focal E30KX to 4000W was also really eye opening. I thought my subs were lacking but all that extra power really really brought them to life. Lots of extra headroom really is key I believe to bringing a system to life when used responsibly.


Sent from my iPhone using Tapatalk


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## rob3980 (Jun 11, 2010)

B5I8 said:


> I installed my (2) HiFi-4250D’s and (1) HD4000.1 two days ago. They are tremendous amps. My Phoenix Gold Ti2’s they replaced were okay but having so much more power on tap really brings my system to life. Very very dynamic, huge in every way except for physical size. Going from 1600W on my pair of Focal E30KX to 4000W was also really eye opening. I thought my subs were lacking but all that extra power really really brought them to life. Lots of extra headroom really is key I believe to bringing a system to life when used responsibly.
> 
> 
> Sent from my iPhone using Tapatalk


This is awesome to hear. I’m waiting on my 6150 and 2 4250s to arrive. Throwing either c7 or utopia Ms on them along with AD W800neo


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## JCsAudio (Jun 16, 2014)

I like that it’s made in the USA. You don’t see that anymore.


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## rob3980 (Jun 11, 2010)

Well I took a leap of faith and my 3 Mmats Hifi amps arrived today. So I snapped a quick pic of 2 of them next to my last class ab amp I have left. The 400.2LX


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## Hillbilly SQ (Jan 26, 2007)

Man that 400.2 is a cow in comparison!


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## quickaudi07 (May 19, 2010)

rob3980 said:


> Well I took a leap of faith and my 3 Mmats Hifi amps arrived today. So I snapped a quick pic of 2 of them next to my last class ab amp I have left. The 400.2LX


Man ohh man.. u go through gear like socks !!

Sent from my Pixel 2 XL using Tapatalk


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## ckirocz28 (Nov 29, 2017)

For what it's worth, here are some pictures highlighting the different controls on the JL Audio RD and XD amps. The XD amps require Y adapters for bridging, the RD amps do not. The plus marks indicate controls that are unique to that amp.


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## rob3980 (Jun 11, 2010)

quickaudi07 said:


> rob3980 said:
> 
> 
> > Well I took a leap of faith and my 3 Mmats Hifi amps arrived today. So I snapped a quick pic of 2 of them next to my last class ab amp I have left. The 400.2LX
> ...


Never put the same gear in the next car. All new gear was a must !


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## rob3980 (Jun 11, 2010)

Hillbilly SQ said:


> Man that 400.2 is a cow in comparison!


If I had the 150.6 i would of thrown that in the pic against all 3 MMATS amps but it found a new home back out in Cali where I got it from.


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## JamesRC (Sep 18, 2017)

*Re: Who’s gone from class AB to class D amps and been happy?*

I was just wondering if they'd come yet. I can't wait to hear your thoughts.


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## Bnlcmbcar (Aug 23, 2016)

*Re: Who’s gone from class AB to class D amps and been happy?*

Here’s another size comparison. 

MMATS 4250 (right side)

MMATS M1000 (left side)

Biketronics 4180 (same size as their 4250 as well)

Zuki ELEETS v1 (A/B)

I really like the versatility of the MMATS 4250. It can power 4 hungry mid bass woofers or drive 2 solid subs with 800 watts each!










Here are Biketronics 4180 and 4250 next to an iPad mini 4 and iPad Pro 11”:


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## rob3980 (Jun 11, 2010)

Bnlcmbcar said:


> Here’s another size comparison.
> 
> MMATS 4250
> 
> ...


I’ve never heard of Biketronics before but those bad boys are small.


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## rob3980 (Jun 11, 2010)

I’m pretty exited for the release of those Audiofrog Amps. Hopefully they are as good as everything else they release.


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## Bnlcmbcar (Aug 23, 2016)

rob3980 said:


> I’ve never heard of Biketronics before but those bad boys are small.


They’ve been at it since 2001. 

A couple factors to consider though:

Most Biketronics do not have gain pots to adjust gain. They usually come stock calibrated so that when the amp sees 2v from RCA source it will reach rated power. But they can calibrate the input voltage to whatever you desire. I had mine set to 4v. In my instance I can adjust gains via Helix DSP Pro which has 8v outputs. Biketronics also does not offer bridging capabilty and the speaker outputs terminals they have probably won’t fit anything lower gauge than 14awg.


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## Hillbilly SQ (Jan 26, 2007)

*Re: Who’s gone from class AB to class D amps and been happy?*



Bnlcmbcar said:


> They’ve been at it since 2001.
> 
> A couple factors to consider though:
> 
> Most Biketronics do not have gain pots to adjust gain. They usually come stock calibrated so that when the amp sees 2v from RCA source it will reach rated power. But they can calibrate the input voltage to whatever you desire. I had mine set to 4v. In my instance I can adjust gains via Helix DSP Pro which has 8v outputs. Biketronics also does not offer bridging capabilty and the speaker outputs terminals they have probably won’t fit anything lower gauge than 14awg.


Well that leaves the people out who think their tweeters need 12g wire:laugh:Seriously though, 14g or even 16g is more than enough for 99% of installs unless you're running BIG power to midbass. The run to sub(s) is so short even 16g will work for them most of the time. I would love to give the 6ch a try at some point. Just need to recover from a couple big purchases lately.


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## Bnlcmbcar (Aug 23, 2016)

*Re: Who’s gone from class AB to class D amps and been happy?*



Hillbilly SQ said:


> Well that leaves the people out who think their tweeters need 12g wire:laugh:Seriously though, 14g or even 16g is more than enough for 99% of installs unless you're running BIG power to midbass. The run to sub(s) is so short even 16g will work for them most of the time.


Very true! But it takes a lot for people to overcome “Bigger is Better” mentality (when it come to audio that is..) :laugh:



Hillbilly SQ said:


> I would love to give the 6ch a try at some point. Just need to recover from a couple big purchases lately.


Last I saw the 6 channel had 3 gain pots for the 3 pairs of channels. The BT4250 has 4 gain pots for each individual channel. The 2180, 4180, and 2250 have no gain pots.


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## NWAudiophile (Apr 8, 2019)

*Re: Who’s gone from class AB to class D amps and been happy?*



Bnlcmbcar said:


> Google “Hypex Class D” and you’ll find they are highly praised throughout the home audio scene by both DIY’ers and boutique High End Amp makers that use the Hypex Modules in their expensive amplifiers.


I realize I'm late to this thread, but I was intrigued to find this reference to Hypex. For home audio, I've owned three generations of Bel Canto switching amps. The first were Tripath designs, and they were so-so. The next were IcePower, a very significant upgrade. I recently purchased their Hypex-based monoblocks (Ncore, not UcD), the REF600M, and they are stunning. This is the technology I want in my car amp someday, even if it would be expensive. Any hope?


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## Bnlcmbcar (Aug 23, 2016)

Mike at Biketronics is cooking something up. They are already familiar with the UcD modules. He also mentioned NCore without me inquiring much except how the car project is coming along:

“The DIY mobile effort is coming along although slower than we wanted - we are doing no less than three different units in parallel and this is tending to slow the release of any one. It's frustrating but we'll have a really nice complement of parts to share. The front ends to all the amps are about at the noise floor of our APx - so really great performance in the drivers of the Hypex amps (including N-core.) Electronic design is complete across the projects and we are in process of putting things in our enclosure(s). Wont be long now.”

So I’m eager to see what they come up with.


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## odj23 (Jul 13, 2010)

*Re: Who’s gone from class AB to class D amps and been happy?*

bnlcmbcar, please keep us in the loop with respect to the Biketronics car offerings. I know I'm interested.


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## Bnlcmbcar (Aug 23, 2016)

*Re: Who’s gone from class AB to class D amps and been happy?*

When is motorcycle season? Is that summer time? Unfortunately, the vibe I get is that we won’t see anything until after that.

I’m sending in 2 of my BT4180’s to increase the input voltage a tad which inherently provides the bonus of a lower THD+N.

I told him there are some people on the forum interested in the upcoming car amp effort:

_Hi Ben,

Thanks for your findings. Yes, please send over the amps and we can promptly bring down the gain.
I'll get you before and after measurement data as well.
*Ya, motorcycle season is getting in the way of our new car amps - you guys are going to appreciate the flexibility and performance for sure.
*
Kind Regards,

-Mike_

A bit cryptic and not a lot of info yet but I’ll relay any further info I get. He’s focused on the core of his business right now which I can’t blame him for. But I’m sure they will be a solid offering. He also has a small hobby/company of building NCore based guitar amps.


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## NWAudiophile (Apr 8, 2019)

*Re: Who’s gone from class AB to class D amps and been happy?*



Bnlcmbcar said:


> When is motorcycle season? Is that summer time? Unfortunately, the vibe I get is that we won’t see anything until after that.
> 
> I’m sending in 2 of my BT4180’s to increase the input voltage a tad which inherently provides the bonus of a lower THD+N.
> 
> ...


Would the car amp be six-channel, do you think?

I have NCore monoblocks in my home system, and I gotta tell you they are amazing.


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## TaylorMade (Feb 11, 2017)

I bet it will be. I bet a 2, 4, and 6 channel. I should be getting my 6-channel and 4 channel next week. It’s just a prototype (6-channel) and you pretty much have to have a DSP or some sort of EQ I would imagine. They have fans too which will be on 100% of the time. And rca to 3.5mm cables for signal inputs. Im excited about it but a little bummed to hear they may be releasing more “car audio friendly” amps. When I talked to Mike it sounded like he wasn’t that interested in the car audio market. But maybe I misunderstood him and he meant he needed to focus on the motorcycle side until he can dedicate time and resources towards a car audio side. Either way, I’ve heard fantastic things about both the UcD technology and biketronics amps so I’m still pretty excited about them.

Unfortunately, this will be my first real build that wasn’t a 4 channel amp on 4 speakers and some subs. This will also be the first time I have more power for my mids and highs than I do for my sub. Also first time with a DSP, aiming tweeters, (maybe) fabricating A-pillars, so my input on the amps can be taken with a grain of salt.


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## Bnlcmbcar (Aug 23, 2016)

*Re: Who’s gone from class AB to class D amps and been happy?*



TaylorMade said:


> They have fans too which will be on 100% of the time...


Correct, the fans are on 100% of the time. My amp location is in a sedan trunk so not a concern. But it should definitely be a factor to consider. I wonder if the fans could be replaced/modded with quieter Noctua fans?



TaylorMade said:


> Im excited about it but a little bummed to hear they may be releasing more “car audio friendly” amps. When I talked to Mike it sounded like he wasn’t that interested in the car audio market. But maybe I misunderstood him and he meant he needed to focus on the motorcycle side until he can dedicate time and resources towards a car audio side..


Like many companies information will be tight until he has a finished product(s) ready for prime time. Haha I can’t speak for him but my guess is he is just plane tired of us car heads asking him to modify his bike amps to appease what we want. Bike amps will most likely will always be his main focus/interest. The car amps will be his “here you go.. now shut up and leave me alone”. (Completely my opinion). 

Also realize NCore modules are much more expensive than UcD modules. The price of his amps aren’t much more than the components they are comprised of but don’t be surprised if there is NCore offerings that cost A LOT of $.

Aside from Biketronics though, I’m still very interested in other people’s thoughts about the thread topic! Similar to how Class A/B became a norm over pure Class A *over time*, which other class d amps out there have made people not look back?


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## Holmz (Jul 12, 2017)

*Re: Who’s gone from class AB to class D amps and been happy?*



Bnlcmbcar said:


> ....
> , I’m still very interested in other people’s thoughts about the thread topic! Similar to how Class A/B became a norm over pure Class A *over time*, which other class d amps out there have made people not look back?


Tubes were used and Hornsby many decent home systems were very modestly powered. Woofers were sometimes 12".

And then...
More piston speakers with lower efficiency, and who really made 100W class-A amps?

Even later... home theatre and music mixed with a lot more low bass really pushed up the watts needed.
Add in a car and class D seems logical.

I am not sure how much louder people will listen, and how much lower the low notes need to go.
There is no rule against mixing class-A, A/B and class-D


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## Bnlcmbcar (Aug 23, 2016)

*Re: Who’s gone from class AB to class D amps and been happy?*



Holmz said:


> There is no rule against mixing class-A, A/B and class-D


 Very true!

So what if we narrow it down to Class D amps that didn’t have you missing the Class A/B it replaced when specifically used for tweeter and midrange duty?


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## Holmz (Jul 12, 2017)

*Re: Who’s gone from class AB to class D amps and been happy?*



Bnlcmbcar said:


> Very true!
> 
> So what if we narrow it down to Class D amps that didn’t have you missing the Class A/B it replaced when specifically used for tweeter and midrange duty?


We often end up back at whether a 20W class-A sounds as good as a 200W class-D, and the advantages of the greater headroom with the higher power class-D.

Measurements of Noise level and THD might be a way to approach it.


----------



## Bnlcmbcar (Aug 23, 2016)

*Re: Who’s gone from class AB to class D amps and been happy?*

Anyone out there have an Audio Precision analyzer?

But even then we start debating on what differences in SNR and THD+N are actually audible.

I’ll leave it be

:dead_horse:


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## Holmz (Jul 12, 2017)

*Re: Who’s gone from class AB to class D amps and been happy?*



Bnlcmbcar said:


> Anyone out there have an Audio Precision analyzer?
> 
> But even then we start debating on what differences in SNR and THD+N are actually audible.
> 
> ...


And I know my Class-AB sounds good because it is class-AB.
(No amount of facts can change my psychology. :surprised: )

I don't know how we could approach it, as A-B testing is also steeped in magic and psychology.
So that dead horse is looking familiar to me too.


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## bitshifted (Nov 19, 2017)

*Re: Who’s gone from class AB to class D amps and been happy?*

Who has switched from A/B to the Helix P Six? Their marketing material boldly states:



> New “Ultra HD Class D” concept which combines the high-end sound quality of Class AB technology with the benefits of Class D amplifiers


The only clue I've picked up is they talk about loads of power on tap, perhaps echoing the idea from earlier in the thread about large power supplies in D class amps.


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## rob3980 (Jun 11, 2010)

My system is finally getting installed on the 16-17th this month. So the MMATS HiFi amps are going in so I will finally get to try these class D amps out. I’m hoping they are as good as I have been told.


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## rob3980 (Jun 11, 2010)

Little class D action. If you look hard enough you can see the dsp.3 in there lol


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## Bnlcmbcar (Aug 23, 2016)

Looking nice! How are they performing in your opinion? My HiFi4250 is powering 2 subs in bridged mode without going past luke warm.


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## rob3980 (Jun 11, 2010)

Bnlcmbcar said:


> Looking nice! How are they performing in your opinion? My HiFi4250 is powering 2 subs in bridged mode without going past luke warm.


I can’t speak about the temps as they are behind my truck seat and i can’t really get to them easily. So far i really like them. No way would i have fit my 3 Mosconi zeros in back and i would have had to upgrade my alternator and so on. I get zero dim with these 3 Mmats amps. I also have a 4250 bridged running 2 Tw5s


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## rob3980 (Jun 11, 2010)

Turned out pretty good.


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## seafish (Aug 1, 2012)

^^^ NICE !!!


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## Porsche (Jun 29, 2008)

how does it sound? who did the install


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## rob3980 (Jun 11, 2010)

Porsche said:


> how does it sound? who did the install


Travis at Sound N Logic in Rice Lake Wi. It sounds good but will sound much better when the speakers break in and I have my tuner tune it. The install work is great. He has done all my installs since 2010. I usually do 1 or 2 cars a year.


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## bbfoto (Aug 28, 2005)

*Re: Who’s gone from class AB to class D amps and been happy?*



rob3980 said:


> Turned out pretty good.





rob3980 said:


> Travis at Sound N Logic in Rice Lake Wi. It sounds good but will sound much better when the speakers break in and I have my tuner tune it. The install work is great. He has done all my installs since 2010. I usually do 1 or 2 cars a year.






seafish said:


> ^^^ NICE !!!


x2!

Travis did some beautiful work there! That should sound amazing when you get it dialed in.


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## rob3980 (Jun 11, 2010)

Here’s Some Better pics


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## SQ_Blaze (Sep 29, 2008)

*Re: Who’s gone from class AB to class D amps and been happy?*

My first Class D amp was a Hifonics Brutus BX1500D, pushing a Rockford Power HX2 15, supported with a 15 farad Alumipro cap.

Then there were a couple of MA Audio HK amps powering a trio of old school JL 10W6's and MB Quart mids and tweets. 

In between these, bought but never installed, and not Class D, I had a sweet Xtant 3300x with both a CM-24x and dual PQM-1 expansion cards.

After that, I had a couple of JL Slash amps, 300/2 v2 & 300/4 v2 powering a SI Mag 4 D2 sub (I wish these were still made) and a pair of Rainbow mids and Dayton tweets. 

Lastly and currently, I'm running the Arc Audio XDi 1200.6 for the entire system.


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## JamesRC (Sep 18, 2017)

*Re: Who’s gone from class AB to class D amps and been happy?*

Looks amazing, Rob.


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## rob3980 (Jun 11, 2010)

JamesRC said:


> Looks amazing, Rob.


Thanks brother.


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## Bnlcmbcar (Aug 23, 2016)

*Re: Who’s gone from class AB to class D amps and been happy?*



odj23 said:


> bnlcmbcar, please keep us in the loop with respect to the Biketronics car offerings. I know I'm interested.


(In case your not following other thread)



Bnlcmbcar said:


> Just spoke some more with Mike. Still no hints of a date but there will be at least a 2 channel NCore offering at 2 x 500 watts. Whole new front end design with a noise floor barely detectible by their Audio Precision Analyzer. It will be ultra high end with a price tag in the $1200-$2000 range. Then they are working on some higher wattage UCD based amps for subwoofer duty.
> 
> Also confirmed from Mike, **Specifically for the BT4250** it can be bridged in series or parallel for 2 ohm or 8 ohm operation with both ways outputting 500 watts!


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## Wiggler (Nov 19, 2015)

3 am and woke up needing to take a piss, and this old man with REAL hearing problems, just remembered to put in his $0.02 here. I always think in terms of decent sonic quality at rock bottom price, and overall current draw and strain on my car's electrical system. Considering those two plus my deteriorating hearing issues, I tend to opt for VERY LOW power (~60w x 4) four channel class A/B, and if I WERE to upgrade my sub amp, probably look for a class D monoblock amp that is also LOW POWER. I just can't seem to part with the overall VALUE FOR THE MONEY factor in the old school (90's) MADE IN USA class A/B everything, versus todays 8-9 year lifespan Class D Made in China junk out there at my price point. Just an old man ranting here, no need to take me seriously, lol! 
P.S. : I have a somewhat Old School JL A4300 class A/B 4 channel, that I don't think I could ever find a car worthy enough to put in, so it just sits inside the box.


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## F150Man (Apr 14, 2017)

My Alpine class D sub amp is great.


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