# What makes an amp considered sound quality or top it the line?



## Selkec (Nov 18, 2018)

I been wondering what makes an amp a sq amp or considered too of the line? Is it the internals and build quality? If so what makes build quality better?
I notice on this forum a lot of love for mmats and arc and read all the time how they are sq and top of the line yet. And the ones mostly mentioned look cheap to me with basic rca connectors and boring looks. So someone enlighten me on what I am missing out on by being so judgemental based on the the cheap appearance. Don’t get me wrong, as I have seen a few from both that do look the part but they aren’t the typical ones people are talking about or posting wtb adds for. 

what other brands and their models are considered sq


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## Holmz (Jul 12, 2017)

Usually marketing and bling.
Low noise and low THD is a good spec to use.


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## 619Tundra (Sep 24, 2020)

Signal to Noise ratio is another. I think the most important is class. Class A is best sounding. But the worse in power consumption.


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## Selkec (Nov 18, 2018)

What’s considered good snr and thd? I see a lot of less the. .1THD. Then there’s some likes helix that says .0017 or something close to that


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## LBaudio (Jan 9, 2009)

high SNR, high damping, high slew rate, ultra low distortion, high bias, big heatsink.....


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## Selkec (Nov 18, 2018)

LBaudio said:


> high SNR, high damping, high slew rate, ultra low distortion, high bias, big heatsink.....


What are these numbers? What is a high snr or high damping spec? 
Is 95snr or 110snr considered high?


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## Selkec (Nov 18, 2018)

So, have been looking at arc audio amps to see what all the fuss is about and I hate to say it but y’all have drank the koolaid or something. 

first thing I notice is they use a lot of buzz phrases and describe fancy sounding technology but they don’t show the important specs like snr except in maybe one amp line. They don’t show thd on any amp either except one higher up line of amps. The rest of the lines there’s no snr or thd or spec sheet to be found on the internet. What are they hiding and why has so many people bough into the bs? Their build quality also is no better than a 180$ amp off Amazon untill you get into the top SE line. 😂😂😂. Oh I did see snr listed on one amp. It was like 105 at full rates power and >85 at 1W which isn’t on the high side and the full power snr is basically useless. So
I gotta know who is paying people to get on here and spread the hype 😂😂😂. 
example of basically useless info








Where’s the snr and thd? Check the manual you say? Oh wait... there is no spec manual


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## bnae38 (Oct 3, 2015)

Selkec said:


> What are these numbers? What is a high snr or high damping spec?
> Is 95snr or 110snr considered high?


Depends if it's at 1W (which it should be), or at full output which is marketing bs.


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## bnae38 (Oct 3, 2015)

Appears you said the same in your next post lol.

Anyway, I love arc audio amps especially the ks line. I've used them for years. Low noise and solid build.


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## Holmz (Jul 12, 2017)

Selkec said:


> What are these numbers? What is a high snr or high damping spec?
> Is 95snr or 110snr considered high?


110dB SNR is good.
Damping factor can be thought of how stiff the output is...
(Like using a bunch cord to lift a box, versus a Kevlar strap... the Bungy cord is the one with a low damping factor)


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## Ge0 (Jul 23, 2007)

Here is a good tutorial:









Here's a set of specs for a truly high end amplifier.
Review and Measurements of Purifi 1ET400A Amplifier | Audio Science Review (ASR) Forum


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## Isaradia (Apr 14, 2020)

well, i typically consider an amp top of the line when the manufacturer doesnt offer any comparable products above it in the line
many important amps specs arent listed by the "regular" brands, doesnt make it a bad amp, just makes it not completely quantified. a lot of people heard actually judge amps based on how they sound when used, which is odd, in a day and age when we can judge everything remotely via google, but unfortunately im in an industry full of bs marketing, everything is made up and the ratings dont matter. because of this, i actually judge equipment based on how it worked the other times i used it. i guess robert zeff could just be turning out a bunch of **** products, investing very little in non-direct marketing, and zapco and arc just have their reputation cuz they look cool, idk. if you want to judge audio equipment, put it in a system where every other component is more capable than it and see where the flaws lie, or send it to a measurement lab. Man, there were no waterfall graphs for the SA6CS's i installed, i was confident they were trash because of this, despite previous sq comp success, but to my surprise i wasnt disappointed with them, despite them clearly being a **** product hiding its flaws by not publishing important quantifications. my buddy is running an inhuman 15" he bought used, didnt even come with basic t/s or even power recommendation. i assured him there would be no way to make it sound good because of this, yet he installed it and urged me to tune it, and for some reason he's happy with it.

/s, your post came off poorly to me. look man, i totally get that there's a huge lack of transparency, quantification, and standardization in the industry, it frustrates me every single day. but what also frustrates me is someone trying to talk **** about a product that, as far as can be told, theyve never used. CDT's website is absolute trash. i tried including their products in my shopping, and couldnt. I didnt discount the product because of it, but i wasnt able to effectively cross-shop, so, since i dont have the funds to buy every single component im considering, and im not geo, so people dont send me whatever i ask for, lol, i wasnt able to consider them. through another series of events i ended up with some CDT products, and they were beautifully made. i didnt get to try them, sent them back to "upgrade" and waiting on the new ones now, but others have had very positive experiences with them, all despite an abhorrent website. idk, ill probably let @Ge0 tell you how they sound (@ANS willing), lol, he's planning on quitting his job because the new forum rule is if you buy something you have to send it to him with a $50 bill so we can accumulate the worlds most comprehensive audio equipment encyclopedia. point is, if you cant tell me what flaws it presents while your eyes are closed and youre listening to it, idgaf what you think about it.


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## cman (Aug 24, 2020)

I agree all manufacturers should post detailed specs, audio precision THD measurements, etc. But you are poorly mistaken about ARC Audio. Their amps (literally all of them even their motorcycle amps) have very low THD numbers.... most have better than average S/N numbers. 85db at 1 watt is a very respectible number.. anything higher than that you will likely never hear the difference... and the build quality.. I think maybe you are blind because the build quality is above average, they almost always use Low ESR caps...everything is well seated, neat assembly, etc. I have disassembled my X2 1200.6 and it was beautiful inside... I cannot disagree with you more... Check out these reviews with Audio Precision testing of ARC amps, they have measurably low distortion.









Arc Audio XDi 600.4 Amplifier Review


There are plenty of choices when it comes to selecting the right amp. The XDi Series from Arc Audio are designed to make the decision easier, with unquestioned sonic performance, comprehensive connection capabilities, a small physical footprint, and the genius of Robert Zeff. To quote Arc...




www.pasmag.com













Arc Audio Moto 600.4 Amplifier Review


Many of us are just as into motorcycles as we are cars. If you are also a motorcyclist that enjoys good tunes in your ride, you will be very happy to learn that the folks at Arc Audio have released a new amplifier that was specifically designed for Harley-Davidson touring bikes, but it can also...




www.pasmag.com





--------------------------------------------------------------------------------------------------
Distortion curve of 300.2 version 1 the oldest version










Damping factor, S/N of KS300.2 V1 the S/N is a 1 watt 2v number... not full power...


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## cman (Aug 24, 2020)

Another stellar review and insane measurements on the signature series...



https://www.arcaudio.com/sites/default/files/2018-01/Arc%204200SE.pdf


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## Isaradia (Apr 14, 2020)

ty cman, the second wonderful post if seen from you today


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## Selkec (Nov 18, 2018)

Hmmmm. Well it seems ridiculous to me and shady to have a full page of big words and fancy talking limbo jumbo yet can when it comes time to post specs they conveniently leave out the important specs 🙄🙄. Come on now. Y’all gotta be smarter than that 😂 
do the cheap generic rca connectors help with sound quality somehow because they definitely DONT add to build quality. A 1000$ amp with same rca connectors as a 25$ Walmart amp. Sorry yall I guess I don’t get it. They definitely have paid off the right people to spread the gospel about them being awesome 👏 
Im out


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## Rainstar (May 22, 2017)

Sometimes how hard it is to get that amp plays a factor. And I am not referring thats only because it is discontinued and no longer made.

If you can walk into a normal store and purchase it or can find it on amazon, crutchfield, best buy, walmart, parts-express, overstock, craigslist, facebook marketplace, down4sound, newegg, sonicelectronix, target, onlinecarstereo, and probably a plethora of other known places. Often they don't exactly stock the cream of the crop stuff. I guess the other thing is if an online review exists its also not top of the line.

depends on who you hang out with, there may be people who do recommend good stuff, but majority I don't trust most people.


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## Isaradia (Apr 14, 2020)

is it possible the cheap rca connectors dont affect sound quality at all? you want numbers? theyve been posted. how do they compare to what youre running?


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## KB789 (Jan 17, 2021)

cman said:


> I agree all manufacturers should post detailed specs, audio precision THD measurements, etc. But you are poorly mistaken about ARC Audio. Their amps (literally all of them even their motorcycle amps) have very low THD numbers.... most have better than average S/N numbers. 85db at 1 watt is a very respectible number.. anything higher than that you will likely never hear the difference... and the build quality.. I think maybe you are blind because the build quality is above average, they almost always use Low ESR caps...everything is well seated, neat assembly, etc. I have disassembled my X2 1200.6 and it was beautiful inside... I cannot disagree with you more... Check out these reviews with Audio Precision testing of ARC amps, they have measurably low distortion.


 Yeah I was confused about the dig towards Arc. I was under the impression that they where a solid upper mid tier brand


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## SloVic (Oct 1, 2016)

Hmm... this may get fun


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## ANS (Sep 23, 2011)

It's quite amazing the amount of misinformation on this subject. Nothing will ever beat the good ole fashioned ear test 😂. Damping factor is not an important factor, it does not greatly influence the sound quality of any speaker unless it is extremely low and the higher the frequency being played the even less important it is. Unfortunately many manufacturers use their own testing methods so specs can be skewed. Real life install ability is another factor. What good is an amplifier that has the best specifications on paper if it inherently picks up large amounts of external interference? I have noticed a lot of amplifiers which utilize forced cooling have poor circuit design where the fan has not been properly isolated in turn creating noise when activated. What good is an amplifier that gets extremely hot to the point of going into protect regardless of how good it sounds....cough DLS CC amplifiers cough lol. I have probably reviewed 30 amplifiers this past year and more than not they do not hit the basic points on my list to make it into my vehicle nor a customer of mine. I have had a lot of success with the Ground Zero amplifier lines minus the brazilian knock offs they rebadged, the new D'Amore amplifiers are extremely impressive, the JL Audio RD, XD, and Slash are solid rocks, but I have never been a big fan of the Arc Audio XDi nor X2 line. They have more floor noise than the competition. The KS and SE line are both rock solid but the forced cooling can be heard at times. There are modifications that can be done to limit the noise. I'm currently testing the new Audison SR lineup, I'm excited to see the results.


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## SloVic (Oct 1, 2016)

ANS said:


> the JL Audio RD, XDI, and Slash or solid rocks, but I have never been a big fan of the Arc Audio XDi nor X2 line.


Do you have an opinion on JL's HD line?


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## ANS (Sep 23, 2011)

SloVic said:


> Do you have an opinion on JL's HD line?


From my experience they are exceptional amplifiers however I do not get to play with them too often. I see more of the XD and RD line.


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## SloVic (Oct 1, 2016)

ANS said:


> From my experience they are exceptional amplifiers however I do not get to play with them too often. I see more of the XD and RD line.


Wasn't sure if it was lack of experience or you had a negative opinion off them. I've never came across any negative reviews and heard them compared to the 2nd generation Alpine PDX line, I was impressed with my F6 and M6 years ago.


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## LR Drvr (Apr 3, 2021)

Isaradia said:


> well, i typically consider an amp top of the line when the manufacturer doesnt offer any comparable products above it in the line
> many important amps specs arent listed by the "regular" brands, doesnt make it a bad amp, just makes it not completely quantified. a lot of people heard actually judge amps based on how they sound when used, which is odd, in a day and age when we can judge everything remotely via google, but unfortunately im in an industry full of bs marketing, everything is made up and the ratings dont matter. because of this, i actually judge equipment based on how it worked the other times i used it. i guess robert zeff could just be turning out a bunch of *** products, investing very little in non-direct marketing, and zapco and arc just have their reputation cuz they look cool, idk. if you want to judge audio equipment, put it in a system where every other component is more capable than it and see where the flaws lie, or send it to a measurement lab. Man, there were no waterfall graphs for the SA6CS's i installed, i was confident they were trash because of this, despite previous sq comp success, but to my surprise i wasnt disappointed with them, despite them clearly being a *** product hiding its flaws by not publishing important quantifications. my buddy is running an inhuman 15" he bought used, didnt even come with basic t/s or even power recommendation. i assured him there would be no way to make it sound good because of this, yet he installed it and urged me to tune it, and for some reason he's happy with it.
> 
> /s, your post came off poorly to me. look man, i totally get that there's a huge lack of transparency, quantification, and standardization in the industry, it frustrates me every single day. but what also frustrates me is someone trying to talk **** about a product that, as far as can be told, theyve never used. CDT's website is absolute trash. i tried including their products in my shopping, and couldnt. I didnt discount the product because of it, but i wasnt able to effectively cross-shop, so, since i dont have the funds to buy every single component im considering, and im not geo, so people dont send me whatever i ask for, lol, i wasnt able to consider them. through another series of events i ended up with some CDT products, and they were beautifully made. i didnt get to try them, sent them back to "upgrade" and waiting on the new ones now, but others have had very positive experiences with them, all despite an abhorrent website. idk, ill probably let @Ge0 tell you how they sound (@ANS willing), lol, he's planning on quitting his job because the new forum rule is if you buy something you have to send it to him with a $50 bill so we can accumulate the worlds most comprehensive audio equipment encyclopedia. point is, if you cant tell me what flaws it presents while your eyes are closed and youre listening to it, idgaf what you think about it.


Another poor excuse is Zapco, even their AP series reflect their Chinese manufacture. Way too much marketing and little to no support or standing behind their products - whoever they are and wherever they are. I noticed a few things on my 150.6 AP that made me want to puke on it then throw it in the dumpster such as the speaker terminal threads stripping due to cheap Chinese metal. The terminal screws were only lightly tightened for bench testing but already failed before installation. Either channel 1 is weaker than the others or the input gain potentiometer is not up to par with the other 5. Very little quality control. That was an $1800 amplifier that is now listed for $2200. Maybe the old school was the b diggity in the day but the new stuff is all Chinese junk, unlike what the Italians and Germans produce, even the British. Fire up a Brax M4 Pro, a Mosconi Zero Line, or a Genesis DMX. Those are all built with pride and truly reflect their build quality. The only thing left in the States that satisfies being referred to as what this forum calls an SQ amplifier is TRU Technology Billet Series. They are top notch and built to last a life time. Aside from that when it comes to car audio quality made amplifiers originating in USA there are none left. They all sold out to China and are mediocre at best. Pardon the rant but nothing of good quality comes from China, even if the American owner patrols the manufacturing plant daily 24 hours a day.


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## ANS (Sep 23, 2011)

LR Drvr said:


> Another poor excuse is Zapco, even their AP series reflect their Chinese manufacture. Way too much marketing and little to no support or standing behind their products - whoever they are and wherever they are. I noticed a few things on my 150.6 AP that made me want to puke on it then throw it in the dumpster such as the speaker terminal threads stripping due to cheap Chinese metal. The terminal screws were only lightly tightened for bench testing but already failed before installation. Either channel 1 is weaker than the others or the input gain potentiometer is not up to par with the other 5. Very little quality control. That was an $1800 amplifier that is now listed for $2200. Maybe the old school was the b diggity in the day but the new stuff is all Chinese junk, unlike what the Italians and Germans produce, even the British. Fire up a Brax M4 Pro, a Mosconi Zero Line, or a Genesis DMX. Those are all built with pride and truly reflect their build quality. The only thing left in the States that satisfies being referred to as what this forum calls an SQ amplifier is TRU Technology Billet Series. They are top notch and built to last a life time. Aside from that when it comes to car audio quality made amplifiers originating in USA there are none left. They all sold out to China and are mediocre at best. Pardon the rant but nothing of good quality comes from China, even if the American owner patrols the manufacturing plant daily 24 hours a day.


I 100% agree in regards to Zapco. Getting help from them is a task you do not want to bet your life on.


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## ANS (Sep 23, 2011)

Does anybody have any real-life experience with the US Acoustics Santa Barbara amplifier? I know it is a cheapo relatively speaking but the specifications look nice and the reviews I read in the past were pretty good.


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## cman (Aug 24, 2020)

ANS said:


> It's quite amazing the amount of misinformation on this subject. Nothing will ever beat the good ole fashioned ear test 😂. Damping factor is not an important factor, it does not greatly influence the sound quality of any speaker unless it is extremely low and the higher the frequency being played the even less important it is. Unfortunately many manufacturers use their own testing methods so specs can be skewed. Real life install ability is another factor. What good is an amplifier that has the best specifications on paper if it inherently picks up large amounts of external interference? I have noticed a lot of amplifiers which utilize forced cooling have poor circuit design where the fan has not been properly isolated in turn creating noise when activated. What good is an amplifier that gets extremely hot to the point of going into protect regardless of how good it sounds....cough DLS CC amplifiers cough lol. I have probably reviewed 30 amplifiers this past year and more than not they do not hit the basic points on my list to make it into my vehicle nor a customer of mine. I have had a lot of success with the Ground Zero amplifier lines minus the brazilian knock offs they rebadged, the new D'Amore amplifiers are extremely impressive, the JL Audio RD, XD, and Slash are solid rocks, but I have never been a big fan of the Arc Audio XDi nor X2 line. They have more floor noise than the competition. The KS and SE line are both rock solid but the forced cooling can be heard at times. There are modifications that can be done to limit the noise. I'm currently testing the new Audison SR lineup, I'm excited to see the results.


From my experience when I had a Dayton DSP with 3.5V RMS output and an ARC X2 I had a slight noise floor. Once I used a line driver or a helix with 6 or 8v output the noise floor was gone. Because the gain was turned all the way down.

Please let me know what you think of the Audison SR lineup. I am very intrested in hearing peoples feedback knowing the long legacy of the SR lineup at audison. I read a review on a russian car audio forum that said he visited Audison HQ and the people at Audison take the listening part when developing amplifiers very seriously... the guy doing the review also said that they had an almost transparent sound to them... not really my thing i like a smooth warm sound, but i know alot of people like a transparent amplifier.


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## cman (Aug 24, 2020)

LR Drvr said:


> Another poor excuse is Zapco, even their AP series reflect their Chinese manufacture. Way too much marketing and little to no support or standing behind their products - whoever they are and wherever they are. I noticed a few things on my 150.6 AP that made me want to puke on it then throw it in the dumpster such as the speaker terminal threads stripping due to cheap Chinese metal. The terminal screws were only lightly tightened for bench testing but already failed before installation. Either channel 1 is weaker than the others or the input gain potentiometer is not up to par with the other 5. Very little quality control. That was an $1800 amplifier that is now listed for $2200. Maybe the old school was the b diggity in the day but the new stuff is all Chinese junk, unlike what the Italians and Germans produce, even the British. Fire up a Brax M4 Pro, a Mosconi Zero Line, or a Genesis DMX. Those are all built with pride and truly reflect their build quality. The only thing left in the States that satisfies being referred to as what this forum calls an SQ amplifier is TRU Technology Billet Series. They are top notch and built to last a life time. Aside from that when it comes to car audio quality made amplifiers originating in USA there are none left. They all sold out to China and are mediocre at best. Pardon the rant but nothing of good quality comes from China, even if the American owner patrols the manufacturing plant daily 24 hours a day.


I own a AP, they are amazing amplifiers, my favorite i've ever heard in my life.. but you are right. the terminals do strip out easy. I am in contact with a chinese manufacturer that makes terminals for all the big amp manufacturers. I can point you in their direction if you need replacement terminals for your AP. They are obviously just a generic design so they are easy to get (you just solder them on with a decent sized soldering iron and flux). But I can tell you from someone who has owned a Skar RP-150.4AB which also has the same terminals, a copied layout, the case is almost the same if not exactly the same.... they sound completely different. The zapco has Sanken transistors, Wima capacitors, LME49720 op amps... its a whole different league of amplifier. But youre right, they dropped the ball with the terminals...


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## Ge0 (Jul 23, 2007)

Nobody mentioned Gold accents and trim. No amplifier is truly high end without this.


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## ANS (Sep 23, 2011)

I have a couple of the Morel MPS amplifiers on order to try. I understand they are not power houses but the sonic performance looks promising.


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## Selkec (Nov 18, 2018)

ANS said:


> Does anybody have any real-life experience with the US Acoustics Santa Barbara amplifier? I know it is a cheapo relatively speaking but the specifications look nice and the reviews I read in the past were pretty good.


I had two of the Lanna 6 channel versions and sent both back. They say the amps are fine when they test but I have another thread testing one of them and it wasn’t fine so after two months of going back and fourth they are gonna refund me and let me move on. I wanted to like the amp so much because when it was working properly it sounded amazing. And it was huge and built like a tank down to the Tiffany rca. It isa perfect example of what I picture when I say “well built”. I don’t think I of small black almost plasticy looking amps with fans on the sides and 50 cent rcas. I don’t care what name you slap on it I would never call an amp like that well built. 









just remembered I did have a Barbara Ann also from US but sold it before hearing it. It too was very nice looking and well built.


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## Petererc (Dec 28, 2016)

cman said:


> I own a AP, they are amazing amplifiers, my favorite i've ever heard in my life.. but you are right. the terminals do strip out easy. I am in contact with a chinese manufacturer that makes terminals for all the big amp manufacturers. I can point you in their direction if you need replacement terminals for your AP. They are obviously just a generic design so they are easy to get (you just solder them on with a decent sized soldering iron and flux). But I can tell you from someone who has owned a Skar RP-150.4AB which also has the same terminals, a copied layout, the case is almost the same if not exactly the same.... they sound completely different. The zapco has Sanken transistors, Wima capacitors, LME49720 op amps... its a whole different league of amplifier. But youre right, they dropped the ball with the terminals...


This rang a bell with something i read the other day, went back and found it.

“PowerClass amplifiers represent what audiophile car audio can be. Unparalleled sound quality stems from multiple factors; top quality toroidal transformers, Sanken® transistors from Japan, and low tolerance Wima® resistors and capacitors from Germany, combining components for one of the highest quality amplifiers”


https://precisionpower.com/product/pc700-4d/


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## cman (Aug 24, 2020)

Petererc said:


> This rang a bell with something i read the other day, went back and found it.
> 
> “PowerClass amplifiers represent what audiophile car audio can be. Unparalleled sound quality stems from multiple factors; top quality toroidal transformers, Sanken® transistors from Japan, and low tolerance Wima® resistors and capacitors from Germany, combining components for one of the highest quality amplifiers”
> 
> ...


you know those Sony XM-GS4’s you posted about buying from sonic electronix...I disassembled one of those and they have Sanken Transistors, Rubycon capacitors, balanced differential inputs. Really quite astonishing for the price. The op amps are JRC NE5532 which are not my personal favorite but they are well regarded by most in the audio community.

This is the first I’ve heard of that precision power.. I’m going to check into that!


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## Petererc (Dec 28, 2016)

cman said:


> you know those Sony XM-GS4’s you posted about buying from sonic electronix...I disassembled one of those and they have Sanken Transistors, Rubycon capacitors, balanced differential inputs. Really quite astonishing for the price. The op amps are JRC NE5532 which are not my personal favorite but they are well regarded by most in the audio community.
> 
> This is the first I’ve heard of that precision power.. I’m going to check into that!


Still rocking the Sony’s no issues. This Amazon Suranjan review is a good one. I dont know enough to upgrade an amp but it is intriguing.
Amazon.com: Sony XMGS4 GS Series 4/3/2 Channel Hi-Res Amplifier (Black): Car Electronics


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## cman (Aug 24, 2020)

Petererc said:


> Still rocking the Sony’s no issues. This Amazon Suranjan review is a good one. I dont know enough to upgrade an amp but it is intriguing.
> Amazon.com: Sony XMGS4 GS Series 4/3/2 Channel Hi-Res Amplifier (Black): Car Electronics


that’s a great review. Yeah what else could you ask for... it’a got the some of the best components available. And the Pasmag review proves how low the distortion is.


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## Destarah (Feb 24, 2019)

I also am curious how the current PowerClass amps would stack up to their predecessors ... I used to own a PowerClass 450 (charcoal edition) and it was a beauty. These new ones have a strange shape to them for sure, so that could definitely be a factor for someone looking to showcase them in the install, but no idea about the guts.


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## JCsAudio (Jun 16, 2014)

I agree with ANS about using your ears but unfortunately many people dont have the means or expertise to do that. I’ve tested a good amount of amplifiers on my test bench back to back.

A few things that I have noticed that stand out and make an amplifier suitable for great sound qaulity:


Low floor noise. I can’t tell you how many amplifiers I’ve tested that produce an audible hiss or floor noise and I hate it. In a vehicle on the move you don’t notice it much, but in a quiet environment it’s noticeable.
Good design, this applies to how they layout the connections, to the actual internal design itself. Its especially important with class D amplifiers where a subpar design means subpar sound. I remember a few of the NVX micro amps I tested sounded especially bad, yet one particular class D was excellent and it didn’t cost a lot either.
Quality components such as how the adjustment/potentiometers or pots feel and the switches click. Usually this is where you start to notice a difference between the $200 to $400 amplifiers and the $500 and up amplifiers.
Efficiency, mostly with class D, the better designs are just more efficient and this is especially important with amplifiers designed to run subwoofers. Mmats M series are excellent there.
Dynamic range, the more robust the power supply is and the more capacitance the amplifier has, the better the range but there is more to it than that.
Resistance to noise, better designs reject noise better.
The pre amplifier section. Better designs allow you to bypass or defeat that part which is important if you are going to use a DSP. The less stuff in the signal path the better.
Heat sink design. Amplifiers that overheat when driven hard in demanding environments are not fun.


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## ca90ss (Jul 2, 2005)

Biggest problem I see with the newer PowerClass amps is the way the connections are handled. Everything is on a small circuit board and then that board is soldered to the main board. Looks like an extra potential failure point and it looks like they had the room to just turn all the connections 90 degrees and mount everything directly to the board.


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## Petererc (Dec 28, 2016)

cman said:


> that’s a great review. Yeah what else could you ask for... it’a got the some of the best components available. And the Pasmag review proves how low the distortion is.


Sonic website shows open box is discontinued and that was good enough reason not to buy another. I just hit up Travis by email and grabbed another for 161.50, damn this website lol


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## Selkec (Nov 18, 2018)

Thanks guys for getting this thread turned aroind into a thread with some good info! Keep it comin!


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## Isaradia (Apr 14, 2020)

If you wanted good info, i think you couldve approached it better. or used google, but i do think having a thread on it makes sense, just maybe next time dont attack things you havent listened to

edited, meant do, not dont


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## ANS (Sep 23, 2011)

Isaradia said:


> well, i typically consider an amp top of the line when the manufacturer doesnt offer any comparable products above it in the line
> many important amps specs arent listed by the "regular" brands, doesnt make it a bad amp, just makes it not completely quantified. a lot of people heard actually judge amps based on how they sound when used, which is odd, in a day and age when we can judge everything remotely via google, but unfortunately im in an industry full of bs marketing, everything is made up and the ratings dont matter. because of this, i actually judge equipment based on how it worked the other times i used it. i guess robert zeff could just be turning out a bunch of *** products, investing very little in non-direct marketing, and zapco and arc just have their reputation cuz they look cool, idk. if you want to judge audio equipment, put it in a system where every other component is more capable than it and see where the flaws lie, or send it to a measurement lab. Man, there were no waterfall graphs for the SA6CS's i installed, i was confident they were trash because of this, despite previous sq comp success, but to my surprise i wasnt disappointed with them, despite them clearly being a *** product hiding its flaws by not publishing important quantifications. my buddy is running an inhuman 15" he bought used, didnt even come with basic t/s or even power recommendation. i assured him there would be no way to make it sound good because of this, yet he installed it and urged me to tune it, and for some reason he's happy with it.
> 
> /s, your post came off poorly to me. look man, i totally get that there's a huge lack of transparency, quantification, and standardization in the industry, it frustrates me every single day. but what also frustrates me is someone trying to talk **** about a product that, as far as can be told, theyve never used. CDT's website is absolute trash. i tried including their products in my shopping, and couldnt. I didnt discount the product because of it, but i wasnt able to effectively cross-shop, so, since i dont have the funds to buy every single component im considering, and im not geo, so people dont send me whatever i ask for, lol, i wasnt able to consider them. through another series of events i ended up with some CDT products, and they were beautifully made. i didnt get to try them, sent them back to "upgrade" and waiting on the new ones now, but others have had very positive experiences with them, all despite an abhorrent website. idk, ill probably let @Ge0 tell you how they sound (@ANS willing), lol, he's planning on quitting his job because the new forum rule is if you buy something you have to send it to him with a $50 bill so we can accumulate the worlds most comprehensive audio equipment encyclopedia. point is, if you cant tell me what flaws it presents while your eyes are closed and youre listening to it, idgaf what you think about it.


I just read this post. Hey now, easy on the website lol 😂, I am trying to help the owner of CDT get some things going. We have a great relationship as he has helped me with designing a speaker line I have been working on utilizing variants of their drivers with several changes/modifications. Lots of exciting things coming soon.


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## Isaradia (Apr 14, 2020)

i dont mean to be negative to the brand, i hoped that saying positive things about the product would let people know that i have a positive opinion of the brand, i was just trying to point out the a website and a product are two very different things and one doesnt dictate the performance of the other, and, hate to say it, but CDT is the largest disparity i can think of, lol


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## ANS (Sep 23, 2011)

Isaradia said:


> i dont mean to be negative to the brand, i hoped that saying positive things about the product would let people know that i have a positive opinion of the brand, i was just trying to point out the a website and a product are two very different things and one doesnt dictate the performance of the other, and, hate to say it, but CDT is the largest disparity i can think of, lol


I understand, I was just giving you a hard time. I agree, the website is out of date and does not display the true quality nor performance of the product. The owner is past the point where many would have retired by now but he has a passion for music and enjoys what he does. I am in the process of assisting them, trying to modernize the brand for the future. There will be some exciting things coming soon from CDT.


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## Rainstar (May 22, 2017)

Isaradia said:


> If you wanted good info, i think you couldve approached it better. or used google, but i dont think having a thread on it makes sense, just maybe next time dont attack things you havent listened to


+1 for the better approach idea. Google really does not get you far. Asking a question on a public forum is the same as asking google since 99.99% of answers aren't great responses unless 99.99% of respondents really know and understand what the top of the line amps are. 

I wonder what the best ice cream flavor is, I highly doubt google or anyone on the ice cream forums know the answer.


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## Isaradia (Apr 14, 2020)

sorry, meant do


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## DaveG (Jul 24, 2019)

ANS said:


> I understand, I was just giving you a hard time. I agree, the website is out of date and does not display the true quality nor performance of the product. The owner is past the point where many would have retired by now but he has a passion for music and enjoys what he does. I am in the process of assisting them, trying to modernize the brand for the future. There will be some exciting things coming soon from CDT.


You have input? Want a money maker? 8"-9" midbass with a neo magnet, less than 3" deep, 8-10mm xmax, and plays down to 50-60hz! Think shallow ZR800! Hope to see it.


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## cman (Aug 24, 2020)

DaveG said:


> You have input? Want a money maker? 8"-9" midbass with a neo magnet, less than 3" deep, 8-10mm xmax, and plays down to 50-60hz! Think shallow ZR800! Hope to see it.


Right... the only good midbass have massive ferrite magnets and cannot fit in my door. GB60 and Scan Gold are the only two... for 6.5's.. im sure 8's are even harder to come by


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## Isaradia (Apr 14, 2020)

literally the answer to my midBASS thread, lol


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## ANS (Sep 23, 2011)

CDT currently has a 6.7 inch with a ferrit motor which plays down to 45hz and is less than 3 inch in depth. From a design standpoint, CDT is currently focusing on current product revisions and a new line of DSP and amplification. Designing a 8 inch midbass with a neo magnet and then manufacturing it would be a large project and the return in profit would not be immediate.


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## ca90ss (Jul 2, 2005)

Didn't they have one similar to the Illusion drivers with the magnet in front of the cone?


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## ANS (Sep 23, 2011)

ca90ss said:


> Didn't they have one similar to the Illusion drivers with the magnet in front of the cone?


Yes, they have had an inverted motor setup since late 1990's. There have been several revisions of it and we are currently working on a revision now.


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## ca90ss (Jul 2, 2005)

ANS said:


> Yes, they have had an inverted motor setup since late 1990's. There have been several revisions of it and we are currently working on a revision now.


I could have sworn I saw an 8" one at one point but that may be another brand I was thinking of.


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## ANS (Sep 23, 2011)

ca90ss said:


> I could have sworn I saw an 8" one at one point but that may be another brand I was thinking of.


They have experimented with an 8 inch version years and years ago but at the time it was not commercially successful. Right now they are finalizing a slim series which utilizes a neo motor. Should be coming out soon.


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## DaveG (Jul 24, 2019)

ANS said:


> CDT currently has a 6.7 inch with a ferrit motor which plays down to 45hz and is less than 3 inch in depth. From a design standpoint, CDT is currently focusing on current product revisions and a new line of DSP and amplification. Designing a 8 inch midbass with a neo magnet and then manufacturing it would be a large project and the return in profit would not be immediate.





ANS said:


> They have experimented with an 8 inch version years and years ago but at the time it was not commercially successful. Right now they are finalizing a slim series which utilizes a neo motor. Should be coming out soon.


So which is it? Kinda contradictory.


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## ANS (Sep 23, 2011)

DaveG said:


> So which is it? Kinda contradictory.


The original post was saying they should make a 8 to 9 inch driver with less than 3 inch of depth and a neo motor. Someone also asked about whether they had an 8 inch inverted motor driver. Here is a more clear answer:

They have been working on a slim 6.5" midbass and coax option which uses a neo magnet, but no 8 inch in the works. They used to have an 8 inch version of the inverted magnet design years ago but it has been discontinued for over 15 years, that was not commercially successful at the time. They are also expanding a DSP line and amplifier line which should hit the shelf within the upcoming months.


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## Selkec (Nov 18, 2018)

Rainstar said:


> +1 for the better approach idea. Google really does not get you far. Asking a question on a public forum is the same as asking google since 99.99% of answers aren't great responses unless 99.99% of respondents really know and understand what the top of the line amps are.
> 
> I wonder what the best ice cream flavor is, I highly doubt google or anyone on the ice cream forums know the answer.


I definitely used google looking on other sites and for actual spec sheets on their amps. All I could find was older models specs or their higher tier amps specs. Any specs I did find they conveniently leave out THD and SNR. I highly doubt this is an accident by them. And my views and thoughts have not changed on them. They still look generic and cheap. Lol

Anyways. There’s other companies that won’t show complete specs also. One of them is Crescendo. I even asked them for the same two specs and they replied back a week later only giving me one of the two. 
but at least they look to be built solid lol. I’ve heard their customer service is basically non existent now.
I want to add to a previous post that US Acoustics when I was dealing with a bad amp had really good customer service. They paid for return shipping and had a replacement shipped out the same day.


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## Destarah (Feb 24, 2019)

I have noticed a disturbing trend of late that if something doesn't show up on a Google search then it is assumed to not exist.
The fact remains that while there are quantifiable differences in the performance of amplifiers as a direct result of the components used to build them and the build quality itself, for a large percentage of the available product the sonic differences are minimal. This is even more pronounced when you consider that it's becoming more popular (and prudent) to use a discrete DSP and simply utilize the amplifier as just an amplifier. All you really need at this point is the ability to adjust gain and a clean signal path. To some extent marketing is necessary to "sell" people on a product being better than what the competition is peddling. There will always be exceptions to the rule, but for what it's worth if you can find a company that is offering more than the industry standard 1 year warranty that really speaks more to it being high-end than whatever specifications you might want to pretend are important.


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## ANS (Sep 23, 2011)

I just finished testing the new D'Amore e400.4 against a Ground Zero GZHA Mini Four. They appear they may come from the same build house but obviously they are both designed differently. In short, the D'Amore is like a baby brother version of the Ground Zero amplifier, both have excellent floor noise performance, but the D'Amore does not have as much power nor overall fidelity. The bass response of the Ground Zero is noticeably better and the high-frequency performance is best described as smoother/more enjoyable. The D'Amore is still a great value given the price point, about $200-$275 less expensive compared to the Ground Zero. It is a great budget option.


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## ANS (Sep 23, 2011)

Destarah said:


> I have noticed a disturbing trend of late that if something doesn't show up on a Google search then it is assumed to not exist.
> The fact remains that while there are quantifiable differences in the performance of amplifiers as a direct result of the components used to build them and the build quality itself, for a large percentage of the available product the sonic differences are minimal. This is even more pronounced when you consider that it's becoming more popular (and prudent) to use a discrete DSP and simply utilize the amplifier as just an amplifier. All you really need at this point is the ability to adjust gain and a clean signal path. To some extent marketing is necessary to "sell" people on a product being better than what the competition is peddling. There will always be exceptions to the rule, but for what it's worth if you can find a company that is offering more than the industry standard 1 year warranty that really speaks more to it being high-end than whatever specifications you might want to pretend are important.


I agree, for the most part, there are too many companies selling an amplifier for $1000 where there are options less than half the cost with similar performance and in some cases, better. A lot of those brands have fancy marketing terms, nice packaging, and a "blingy" website.


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## 619Tundra (Sep 24, 2020)

Orion HCCA amps are a solid choice if you're lucky to get ahold of one. Class A.


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## Holmz (Jul 12, 2017)

So the answer to the question of, "what makes an amplifier considered sound quality or top of the line", are:

factual things, like high SNR, low THD, build etc.
perception, mRketing, public opinion

I have the old McIntosh becuase they tick all the boxes, and then the bonus is that I can also lord it over in a social signalling sense.
I could probably gut them and run class-D alps and just light them and have the needles quiver, and psychologically we agree that they are great.

If one is not building a show car, then just go for some good amps with high SNR and low THD+N. Having the amps not hiss like a pack of vipers is always reassuring, IMO.


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## ANS (Sep 23, 2011)

Check this out for a nice-looking option for little money:









Soundmagus B4.600PRO Pure Class AB 4 Channel Amplifier | eBay


Find many great new & used options and get the best deals for Soundmagus B4.600PRO Pure Class AB 4 Channel Amplifier at the best online prices at eBay! Free shipping for many products!



www.ebay.com










B4.600PRO - B Series - SoundMagus Technology







www.soundmagus.com


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## SkizeR (Apr 19, 2011)

Selkec said:


> I been wondering what makes an amp a sq amp or considered too of the line?


how many forum members say its the best after one person they don't even know says its good


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## jheat2500 (Mar 1, 2021)

ANS said:


> Check this out for a nice-looking option for little money:
> 
> 
> 
> ...


What would the import fees run? Is the cost going to double once it lands in the US?


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## ANS (Sep 23, 2011)

jheat2500 said:


> What would the import fees run? Is the cost going to double once it lands in the US?


I doubt it would double, it may increase another $100, but it still looks to be a nice option


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## Selkec (Nov 18, 2018)

jheat2500 said:


> What would the import fees run? Is the cost going to double once it lands in the US?


I’ve wondered how those amps are for a while but never heard anyone talk about them. They look nice but how do they sound


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## Leet (Apr 5, 2021)

This makes an amp SQ. 😊


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## doeboy (May 2, 2012)

How much you spend combined with the placebo effect.


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## st1nki4a (Feb 8, 2012)

Talking about amps which one would you choose and why:
audison av 5.1k
ground zero gzua 6.200sq plus
Helix C four?
I can't decide. I have Helix dsp.2 and Helix m one so there is no problem to pick a 4 channel amp instead 5 chanel. Helix msix will be bridged to midbass. So looking for mids and high amp. Thank's for the advice.

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## cman (Aug 24, 2020)

st1nki4a said:


> Talking about amps which one would you choose and why:
> audison av 5.1k
> ground zero gzua 6.200sq plus
> Helix C four?
> ...


I would take the Ground Zero or the Helix. They both have very low distortion.. the helix C four is better on paper with a crazy high damping factor and signal to noise... but I like that the ground zero has small and big channels plus has op amp sockets so you can swap the op amps... it even comes with burr brown ones.

I like warm amps, I know the helix sounds clinical and precise like brax from what I hear at least... it’s all mosfets, no bipolar transistors. The ground zero has bipolar transistors on the output.

really personal preference at that point... but the Audison I wouldnt even put in the same league.. only their thesis amps could keep up with the ground zero and C four


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## clearlyloud&crystalclear (Jun 1, 2017)

Well, I'm the king of lurking (mostly reading and never posting) but this has always been a very interesting topic for me. I am just getting back into car audio after being heavily into it in the 90s and having a short budget-as my mother would say champagne taste on a beer budget. However, after entering the adult world as a radio production and studio engineer I have been blessed(and cursed) to work in some very fine environments with absolutely phenomenal audio monitoring. I think one can produce very respectful results in the car environment...but not beat a properly conditioned studio listening environment with absolutely no outside noise and every wall dampened and minus reflection. But since I am in Cali and spend ridiculous amounts of time driving, I decided to attempt to build a system that was dedicated to both stages of my life...as nearly balanced, clean and noise free music as possible that can also be played insanely loud without distortion or losing balance. I like all music genres literally, the only exception is there are very, very few EDM selections I can get into, so I also wanted flexibility so the diversity of music from Miles to Metallica to Chopin to Spice 1 could be played. Now I also happen to be into vinyl and believe that analog has and likely will be better than digital (certainly in the recording environment) so it has been an adventure finding the right products. 32 bit 192k has definitely made it a battle. But I grew up in an era where the word digital would get you laughed out of a sq conversation. 
I will say right out front that I was looking for American products because that is who I am and while I don't knock(or at least frequently) other countries output, I do think pride of product and build quality suffer in certain parts of the world. I think the Germans and in many cases the Italians do a good job here, but I support the good old US of A(Blame those 80s made in America ads I guess...).
That said I have gained maturity and wisdom(still learning...never too old to stop), I have developed a pet peeve about (many) consumer level products spending hundreds of k on marketing for an inferior or rebranded product and the world falling for the flim flam. Hey Uncle, my Beats by Dre headphones are the best...those sennheizer hd look boring, they suck kinda thing. My Mackie mixer is better than your PR&E board kind of thing. You get the point. Most high quality anything performs and isn't as flashy as consumer level products because A it performs and B it doesn't have to be as its selling point. 
Anyway, I like OP wanted a SQ amp that was solid, reliable and capable of running cool with no fan noise and danger of over heating. I also didn't want to "show off" a slew of amps and eliminate usage of my seating or cargo storage of my vehicle so 1 or 2 amps max. The made in America vs assembled in America thing got tricky really quick but I settled on Mmats hifi 6150D to power Steven's audio MB and Horns.
All I'll say is the specs are absolutely important, but the ear test in the end is the key. Low noise floor, distortion, and function are key. Mmats does a great job here. I never understood the obsession with looks being considered in a product made to be listened to, sure you don't want it to intentionally stand out as looking crappy, but I don't think any women are going to get moist over seeing that shiny amp in your custom amp rack that has the doodads and the bells and whistles...that is why it is called "sound quality". To say something sucks or isn't SQ because it looks boring strikes me as being sophomoric and illogical. Anyway, I've heard at least 3 systems extensively that used old school McIntosh amps that were the epitome of SQ systems and I'm trying to get close using American parts(caved on the Helix Dsp pro mk2 because I already had one). My advice would be, do your research and then listen to as much as possible. Then bite the bullet and get that build going and enjoy...you'll be middle aged still wondering what SQ amps to buy and have a completely different car and have to start over.
Get as clean, efficient and noise free signal and amplification as you can and run them through speakers with adequate sensitivity, low distortion and the same adequacy and do a proper install and enjoy that ish....life is short. 

Here are the Mmats specs if interested:









Sorry for the long post...it's 6:45 and it's been a long, isolatory quarantine spent mostly solo in a sound proof room...but it makes you realize what is important in life is the doing and not sitting around waiting to do.


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## cman (Aug 24, 2020)

clearlyloud&crystalclear said:


> Well, I'm the king of lurking (mostly reading and never posting) but this has always been a very interesting topic for me. I am just getting back into car audio after being heavily into it in the 90s and having a short budget-as my mother would say champagne taste on a beer budget. However, after entering the adult world as a radio production and studio engineer I have been blessed(and cursed) to work in some very fine environments with absolutely phenomenal audio monitoring. I think one can produce very respectful results in the car environment...but not beat a properly conditioned studio listening environment with absolutely no outside noise and every wall dampened and minus reflection. But since I am in Cali and spend ridiculous amounts of time driving, I decided to attempt to build a system that was dedicated to both stages of my life...as nearly balanced, clean and noise free music as possible that can also be played insanely loud without distortion or losing balance. I like all music genres literally, the only exception is there are very, very few EDM selections I can get into, so I also wanted flexibility so the diversity of music from Miles to Metallica to Chopin to Spice 1 could be played. Now I also happen to be into vinyl and believe that analog has and likely will be better than digital (certainly in the recording environment) so it has been an adventure finding the right products. 32 bit 192k has definitely made it a battle. But I grew up in an era where the word digital would get you laughed out of a sq conversation.
> I will say right out front that I was looking for American products because that is who I am and while I don't knock(or at least frequently) other countries output, I do think pride of product and build quality suffer in certain parts of the world. I think the Germans and in many cases the Italians do a good job here, but I support the good old US of A(Blame those 80s made in America ads I guess...).
> That said I have gained maturity and wisdom(still learning...never too old to stop), I have developed a pet peeve about (many) consumer level products spending hundreds of k on marketing for an inferior or rebranded product and the world falling for the flim flam. Hey Uncle, my Beats by Dre headphones are the best...those sennheizer hd look boring, they suck kinda thing. My Mackie mixer is better than your PR&E board kind of thing. You get the point. Most high quality anything performs and isn't as flashy as consumer level products because A it performs and B it doesn't have to be as its selling point.
> Anyway, I like OP wanted a SQ amp that was solid, reliable and capable of running cool with no fan noise and danger of over heating. I also didn't want to "show off" a slew of amps and eliminate usage of my seating or cargo storage of my vehicle so 1 or 2 amps max. The made in America vs assembled in America thing got tricky really quick but I settled on Mmats hifi 6150D to power Steven's audio MB and Horns.
> ...


The crazy thing is that Mmats hifi amps use IRS class D driver chips just like almost all other class D car amplifiers cheap and expensive (except biketronics, helix, and maybe a couple others)
It’s all in the feedback loop of the class D circuit, your output filtering, and the input section (good noise rejection) that will make it break a car amplifier. Just because an amp test good on a test bench on a lab power supply doesn’t mean it will be clean in a vehicle. I look for amps with filter chokes on the power supply, balanced differential inputs, etc as some of the tell tale signs of whether the amp engineers designed it on a test bench or if they designed it and tested with an actual vehicle with alternator noise and what not in mind... Very tricky in my opinion to get right...


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## clearlyloud&crystalclear (Jun 1, 2017)

cman said:


> The crazy thing is that Mmats hifi amps use IRS class D driver chips just like almost all other class D car amplifiers cheap and expensive (except biketronics, helix, and maybe a couple others)
> It’s all in the feedback loop of the class D circuit, your output filtering, and the input section (good noise rejection) that will make it break a car amplifier. Just because an amp test good on a test bench on a lab power supply doesn’t mean it will be clean in a vehicle. I look for amps with filter chokes on the power supply, balanced differential inputs, etc as some of the tell tale signs of whether the amp engineers designed it on a test bench or if they designed it and tested with an actual vehicle with alternator noise and what not in mind... Very tricky in my opinion to get right...


I definitely do not disagree that there are nuances. But I do believe that there can be a certain level where it no longer is audibly discernable. But one thing is for certain, I will take a high performing unassuming looking product over a mediocre performer that looks like Phoebe Cates on the diving board(how's that for an old reference?). I definitely think money shouldn't be wasted but many of us spend more time fantasizing...err researching then getting our projects going and we waste a lot of life. And as some on here have said at the end of the day, the ear test is the number one most important test. Unless you are competing it is really the only test other than reliability and the need to fire up when you want it too and function as intended. 
And to someone else earlier in the threads point...a 3 year warranty is a pretty confident statement for that. 
I'm sure there are plenty of amps with similar or better bench test...just reiterating that it looks plain so it must not be high quality is flawed thinking.


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## ckirocz28 (Nov 29, 2017)

DaveG said:


> You have input? Want a money maker? 8"-9" midbass with a neo magnet, less than 3" deep, 8-10mm xmax, and plays down to 50-60hz! Think shallow ZR800! Hope to see it.


I vote for a target Xmax of 12 mm, and wouldn't be disappointed with 9-10 mm, also a 6 1/2 incher would be great.


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## ckirocz28 (Nov 29, 2017)

Dammit! It's "noise floor" not "floor noise"! Not meant for you @clearlyloud&crystalclear.


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## st1nki4a (Feb 8, 2012)

cman said:


> I would take the Ground Zero or the Helix. They both have very low distortion.. the helix C four is better on paper with a crazy high damping factor and signal to noise... but I like that the ground zero has small and big channels plus has op amp sockets so you can swap the op amps... it even comes with burr brown ones.
> 
> I like warm amps, I know the helix sounds clinical and precise like brax from what I hear at least... it’s all mosfets, no bipolar transistors. The ground zero has bipolar transistors on the output.
> 
> really personal preference at that point... but the Audison I wouldnt even put in the same league.. only their thesis amps could keep up with the ground zero and C four


Is Audison 5.1k that bad compared to the other two amps?

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## miniSQ (Aug 4, 2009)

SkizeR said:


> how many forum members say its the best after one person they don't even know says its good


Or after they just bought it.


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## SkizeR (Apr 19, 2011)

miniSQ said:


> Or after they just bought it.


Exactly. I can name a few forum members that buy something new, rave about it, and then 4 months later "don't like it"


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## miniSQ (Aug 4, 2009)

SkizeR said:


> Exactly. I can name a few forum members that buy something new, rave about it, and then 4 months later "don't like it"


I'm guilty of that with SI RM-12. LOVED it, but i sold it. But only because it weighed a ton and i prefer lighter subs.


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## st1nki4a (Feb 8, 2012)

I also bought helix m six and didn't liked it for mids and highs but for midbass is ok. Skizer what would you say about Audison 5.1k and Helix C four? I'm so sory that you are so far away from here and here we don't have good installers like in the US....

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## Cutaway (May 5, 2020)

I personally really like the Helix C Four amplifiers. I bought mine kind of on a whim. The only down side i have found with them is the physical size, they pretty big. I have zero floor noise with mine with a gain overlap (8 channels ranging from 3 db - 6 db). I live in the desert and have never had thermal issues with them. They are not very powerful BUT they produce a ton of volume even when driving 85+ mph with the windows down. they sound "Strong" and neutral but, i dont know how much of that is tuning and settings. I went through a few different brands and class type (A/B, D, H/D) before buying these and have been supper happy...... with one exception, they use MOSFET vs Bi-Polar outputs. I have always preferred the sound of Bi-Polar (Non-Triple Darlington design). But i dont know if im ready to give up the C 4's just for an experiment


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## trunks9_us (Oct 25, 2007)

cman said:


> I own a AP, they are amazing amplifiers, my favorite i've ever heard in my life.. but you are right. the terminals do strip out easy. I am in contact with a chinese manufacturer that makes terminals for all the big amp manufacturers. I can point you in their direction if you need replacement terminals for your AP. They are obviously just a generic design so they are easy to get (you just solder them on with a decent sized soldering iron and flux). But I can tell you from someone who has owned a Skar RP-150.4AB which also has the same terminals, a copied layout, the case is almost the same if not exactly the same.... they sound completely different. The zapco has Sanken transistors, Wima capacitors, LME49720 op amps... its a whole different league of amplifier. But youre right, they dropped the ball with the terminals...


I have two Allen head stripped out but they seat fine with speak wire inside it I use 12 gauge I angle the Allen head in and it works fine I’ll be selling my 150.6 ap amps and I’ll note this as well and if you think someone is gonna try to haggle me down over this then they are wrong because i guarantee you someone will want both these amps as I see them sell so fast all the time. I don’t see a reason to lower or discount a price on a item that works perfectly fine when the speaker wire is plugged in. If someone wants to complains about it not screwing down with out speaker wire well why are you messing your amps with our speaker wires? They dont fall out you have to manually take them out so yes I see zero reason why I would need to drop my price because I the end it works just fine and I know someone just like me doesn’t care.

And I love zapco the sq is top notch!


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## Patriot83 (May 10, 2017)

Every great amp designer I've seen talk about amps say the power supply is BY FAR the most important part of the amp. Heinz Fischer (Audiotec Fischer), Robert Zeff and many others say they put lots of R&D in this area in their interviews. Next is noise filtering. Tony D'amore explained that pretty well when he was launching his D'amore Engineering amps. Internal components would seem to be very important also but there are lots of $1000+ amps with avg or below avg transistors, caps, etc. The Sony amp mentioned here earlier (XM-GS4) has top notch components for $250 and pretty much everyone says that amp sounds great. Sony could do it for $250. So why do the other amp companies use lesser parts in their $1000 amps? I had one of those $1000 amps with lesser parts and it sounds completely fine, no complaints. Here's a interesting interview with Heinz Fischer for anyone interested:


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## cman (Aug 24, 2020)

Patriot83 said:


> Every great amp designer I've seen talk about amps say the power supply is BY FAR the most important part of the amp. Heinz Fischer (Audiotec Fischer), Robert Zeff and many others say they put lots of R&D in this area in their interviews. Next is noise filtering. Tony D'amore explained that pretty well when he was launching his D'amore Engineering amps. Internal components would seem to be very important also but there are lots of $1000+ amps with avg or below avg transistors, caps, etc. The Sony amp mentioned here earlier (XM-GS4) has top notch components for $250 and pretty much everyone says that amp sounds great. Sony could do it for $250. So why do the other amp companies use lesser parts in their $1000 amps? I had one of those $1000 amps with lesser parts and it sounds completely fine, no complaints. Here's a interesting interview with Heinz Fischer for anyone interested:



You will notice in almost all Zeff amps you see coils/filter chokes....even more in the high end ones. Helix ones like the C Four and HXA400 have them, they are just under the chrome covers.. one is a transformer and the other one is a choke/filter - very critical when using equipment inside a car. Cheap amps do not have them. An electrical system in an automobile is full of noise. I will post a couple ARC amps and then a Skar audio RP-150.4AB at the bottom to show they are missing in cheap designs... the Skar only has a couple filtering caps.. dont get me wrong there are many amps worse than the Skar.. I have owned one and they work suprisingly well relative to their price - but they are obviously lacking anything special...


*ARC XDI 1200.6 (below)*










*ARC KS/KAR series V3 (below)*











*Zapco** Z-150.4AP (below)*










*
Skar RP-150.4AB (below)*


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## cman (Aug 24, 2020)

trunks9_us said:


> I have two Allen head stripped out but they seat fine with speak wire inside it I use 12 gauge I angle the Allen head in and it works fine I’ll be selling my 150.6 ap amps and I’ll note this as well and if you think someone is gonna try to haggle me down over this then they are wrong because i guarantee you someone will want both these amps as I see them sell so fast all the time. I don’t see a reason to lower or discount a price on a item that works perfectly fine when the speaker wire is plugged in. If someone wants to complains about it not screwing down with out speaker wire well why are you messing your amps with our speaker wires? They dont fall out you have to manually take them out so yes I see zero reason why I would need to drop my price because I the end it works just fine and I know someone just like me doesn’t care.
> 
> And I love zapco the sq is top notch!



Don't blame you they are special amps.. and prices are only going up on everything


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## 156546 (Feb 10, 2017)

These look like the output filter to me.


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## Se7en (Mar 28, 2007)

DaveG said:


> You have input? Want a money maker? 8"-9" midbass with a neo magnet, less than 3" deep, 8-10mm xmax, and plays down to 50-60hz! Think shallow ZR800! Hope to see it.


How about a Dyn MW182? Satisfies all your performance criteria, and is a fraction of the mounting depth of the ZR..


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## Selkec (Nov 18, 2018)

cman said:


> You will notice in almost all Zeff amps you see coils/filter chokes....even more in the high end ones. Helix ones like the C Four and HXA400 have them, they are just under the chrome covers.. one is a transformer and the other one is a choke/filter - very critical when using equipment inside a car. Cheap amps do not have them. An electrical system in an automobile is full of noise. I will post a couple ARC amps and then a Skar audio RP-150.4AB at the bottom to show they are missing in cheap designs... the Skar only has a couple filtering caps.. dont get me wrong there are many amps worse than the Skar.. I have owned one and they work suprisingly well relative to their price - but they are obviously lacking anything special...
> 
> 
> *ARC XDI 1200.6 (below)*
> ...


does this us acoustics Lanna that’s supppsed to be their SQ amp have those filter / chokes










does that 250$ Sony use them? Why don’t more people use those sony if they are made with good components? Because they don’t cost a lot or have a fancy name most likely?


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## ckirocz28 (Nov 29, 2017)

Selkec said:


> does this us acoustics Lanna that’s supppsed to be their SQ amp have those filter / chokes
> 
> View attachment 318188
> 
> ...


I could be wrong, but I believe those output filters (chokes) are only needed on class d amps to filter out the ultra high frequency noise from the switching (digital) power supply. Class a/b amps shouldn't need those.


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## cman (Aug 24, 2020)

all the


GotFrogs said:


> These look like the output filter to me.
> View attachment 318152



youre right those are not on the inputs, they are on the output


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## cman (Aug 24, 2020)

ckirocz28 said:


> I could be wrong, but I believe those output filters (chokes) are only needed on class d amps to filter out the ultra high frequency noise from the switching (digital) power supply. Class a/b amps shouldn't need those.



Yes, that is the only amp they are "needed" in - just another implementation of them. in the case of the ARC xdi it has the choke on the battery inputs by the fuses and then its shielded output inductors in those square boxes on the right.


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## cman (Aug 24, 2020)

Selkec said:


> does this us acoustics Lanna that’s supppsed to be their SQ amp have those filter / chokes
> 
> View attachment 318188
> 
> ...



The Lanna


Selkec said:


> does this us acoustics Lanna that’s supppsed to be their SQ amp have those filter / chokes
> 
> View attachment 318188
> 
> ...



the US Acoustics does not.

here’s some pics of one of my Sony XM-GS4’s.
I don’t know how sony makes any money selling these Amplifiers… rubycon capacitors.. Sanken transistors… alps potentiometers… and yes it looks like there’s a couple chokes on the battery inputs. it is nice, kind of low on uF of rail capacitance..


I suspect Sony has had long-term relationships with these suppliers in Japan and has been able to get the price down on these components to where it’s a reasonably priced amp.

Sanken, alps, rubycon, JRC op amps, are ALL Japanese companies… either that or a lot of these companies have more profit margin than we realize and Sony just has almost no margin on this amp.

it objectively tests with like 0.02% THD so pretty nice… although most JL audio amps like the JL xdv2 class D amps test about the same if I recall correctly…

it’s hard to screw up an amp nowadays… but I enjoy splitting hairs for entertainment


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## Selkec (Nov 18, 2018)

The Sony could be a nice tweet and mid amp I bet. Could the rail capacitance be upgraded?


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## Petererc (Dec 28, 2016)

cman said:


> The Lanna
> 
> 
> 
> ...


Tha markup on the Sony even makes the margin smaller. Sonic was selling open box gs-4 for 160ish $ and I am sure they made a profit.


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## JCsAudio (Jun 16, 2014)

Hmm, I might have to get that Sony amp and try it on my amp switcher in my blind subjective tests. Too bad I just put it all away.

Component selection is important I'm sure but overall design and how it all comes together is paramount in my opinion. Just having high end components along is no guarantee the amp will sound better. Output impedance, headroom, capacitance, you name it, it all makes a difference. Its a very complex relationship inside there. No one size fits all soluttions there!

PS, I believe the Sony XM GS4 is a class A/B amplifier.


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## doeboy (May 2, 2012)

I think the placebo effect combined with how much $ a person drops into a product has a large influence on what they 'believe' is better. Without a blind test prior to purchase who knows what you would really think is 'good'. I think that would be a great thing to do with somebody that doesn't know what they want. Just show up. Listen to a bunch of favorite songs in a variety of different systems and then rate what they like the best. Sound is in the eye of the beholder just as food is. I always thought the best cook was the one that could turn cheap ingredients into a world class flavor. The same can apply to DIY car audio.


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## Selkec (Nov 18, 2018)

What arc audio amps use sanken, rubycon etc?


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## cman (Aug 24, 2020)

Selkec said:


> What arc audio amps use sanken, rubycon etc?


I know some of the lower models like all the class G/H just use standard stuff like TIP34/35 from ST Microcontroelectronics for transistors. 

then as far as I know all the caps in all the ARC amps are “Arc Audio” Branded low ESR. So they have them made specially for them.. 

The Signature ARC has Sanken Transistors according to marketing material, although I have not personally seen the inside or any pictures of it.. so take that FWIW until you see a picture.


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## Holmz (Jul 12, 2017)

doeboy said:


> I think the placebo effect combined with how much $ a person drops into a product has a large influence on what they 'believe' is better. Without a blind test prior to purchase who knows what you would really think is 'good'. I think that would be a great thing to do with somebody that doesn't know what they want. Just show up. Listen to a bunch of favorite songs in a variety of different systems and then rate what they like the best. Sound is in the eye of the beholder just as food is. I always thought the best cook was the one that could turn cheap ingredients into a world class flavor. The same can apply to DIY car audio.


No, never


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## dsw1204 (Mar 23, 2015)

Just throwing this out there, for the heck of it. This amp may have the most impressive specs I have seen. It is very expensive, but if I won the Powerball this may be the one I would purchase. Or, maybe two of them.









BRAX MX4 PRO


BRAX MATRIX MX4 PRO | 4-Channel Amplifier | Class AB | 4 x 300 Watts RMS at 4 Ohms | 4 x 240 Watts RMS at 2 Ohms | Bridged 2 x 480 Watt at 4 Ohms




www.audiotec-fischer.de


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## MrHarris (Feb 3, 2011)

dsw1204 said:


> Just throwing this out there, for the heck of it. This amp may have the most impressive specs I have seen. It is very expensive, but if I won the Powerball this may be the one I would purchase. Or, maybe two of them.
> 
> 
> 
> ...


how much does this cost in USD?


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## dsw1204 (Mar 23, 2015)

MrHarris said:


> how much does this cost in USD?


I do believe about $6500 USD.


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## Jln213 (Mar 5, 2020)

Old school mmats, linear power, Phoenix gold zpas, mtx thunder, soundstream class a or refs, precision power, Fosgate, kicker, anything made in the usa in the 90s. Or some early 2ks. I have around 250 old school 90s amps. I would use them over any modern amp. As long as they have been recapped if needed or well taken care of. I also have some modern top of the line amps, mosconi, helix, Genesis, audison, etc. But I still always fall back on the US made class ab stuff from the 90s.


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## Jln213 (Mar 5, 2020)

Orion, a/d/s, and some fine Japanese examples, clarion, eclipse, alpine, pioneer, my guilty favorite is old school crossfire cfa hc models. I have 3 30hcs and those things are amazing.


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## Jln213 (Mar 5, 2020)

Jln213 said:


> Orion, a/d/s, and some fine Japanese examples, clarion, eclipse, alpine, pioneer, my guilty favorite is old school crossfire cfa hc models. I have 3 30hcs and those things are amazing.


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