What are the best audio amplifiers in consumer audio?

[bang4bucker]

The Pass Labs X600.8 600 Watt Monoblock is rated 600 Watts RMS into 8 Ohms, 1,200 Watts RMS into 4 Ohms.
I am not arguing the point, but those measurements were at 22 volts or 60.5 watts. Not exactly high power. The Passlabs amp measures superbly at 5 volts, but nothing to write home about at 1/10'th its power rating.

Eyeballing these charts to try to use consistent scaling:

View attachment 14452

At 5 volts, the 2'nd harmonic is 64 DB down and the 3'rd is 80 DB down.

View attachment 14453

At 22 volts, the 2'nd harmonic is at 58 DB down and the 3'rd is 60 DB down, at it keeps going with the 5'th harmonic at -90 relative to the referenced tone.


The Emotiva XPA-1 Gen 2 mono-block is 600 watts into 8 ohms, 1,000 watts into 4 ohms.

View attachment 14454

At 12.5 watts, the 2'nd harmonic is 95 DB down and the 3'rd is 104 DB down, 4'th is 110 DB down, etc. into the noise

View attachment 14455

At 600 Watts (69.2VRMS) , the 2'nd harmonic is at 100 DB down and the 3'rd is 88 DB down, 4'th 103 DB down, 5'th 100 with odd harmonics remaining at -110.

I don't know which one sounds better, but it is clear which one measures better

- Rich

i know you use P=V^2 x R formula to get that 60.5 watts number. but we don't know how much the current (I), right ? afaik, even passlab class AB amps are biased high so when idling are drawing about half their rated power.

https://passlabs.com/articles/leaving-class-a

so i believe these amps produce more current compared to other class AB amps even at the same power output (same watt) and same load.

you should also notice that those graphs have different y axis scale :dBV versus dBrA. and what's more important is the passlab amp measurements are ABOVE 0 db scale. with 3 db equals twice power, i think it's a mismatch comparing those graphs.

 

[PENG]

Of course if you design the amp to be fully differential from input to output, use the right amount of feedback, have a robust power supply, etc, you can lower both even and odd order distortions. The type of logic where one should deliberately make a certain type of distortion higher than another doesn't work in areas of amplification requiring extreme sensitivity and amplification of small signals such as the telcom world. I don't think Audio should be the only exception to this rule b/c it doesn't fly in ANY other industry using amplifiers from DC to LIGHT!

You don't have to convince me at all as I prefer accuracy so I do not believe in distortion being a good thing regardless. I just wanted bang4buck to know that apparently it may not be true that most people prefer even to odd, specifically 2nd to 3rd. I used to think it was a fact that even harmonic distortion always more pleasing, at the same %. After reading that article, I now suspect this is not a black and white thing.

 

[PENG]

i know you use P=V^2 x R formula to get that 60.5 watts number. but we don't know how much the current (I), right ? afaik, even passlab class AB amps are biased high so when idling are drawing about half their rated power.

https://passlabs.com/articles/leaving-class-a

so i believe these amps produce more current compared to other class AB amps even at the same power output (same watt) and same load.

you should also notice that those graphs have different y axis scale :dBV versus dBrA. and what's more important is the passlab amp measurements are ABOVE 0 db scale. with 3 db equals twice power, i think it's a mismatch comparing those graphs.

The output current for the same load would have to be the same. The input current could be higher but the reason why they biased higher is to achieve better linearity at low volume and at rated output the difference between the two should not be that significant. The Passlab would be quite inefficient at lower output level.

 

[RichB]

i know you use P=V^2 x R formula to get that 60.5 watts number. but we don't know how much the current (I), right ? afaik, even passlab class AB amps are biased high so when idling are drawing about half their rated power.

https://passlabs.com/articles/leaving-class-a

so i believe these amps produce more current compared to other class AB amps even at the same power output (same watt) and same load.

you should also notice that those graphs have different y axis scale :dBV versus dBrA. and what's more important is the passlab amp measurements are ABOVE 0 db scale. with 3 db equals twice power, i think it's a mismatch comparing those graphs.

Yep, I was working with what was available, but I tried the eyeball the positive scale to describe the level of distortion below test tone(s).

The higher the resistance the more current is required to maintain class-A.
Passlabs makes beautiful product.

- Rich

 

[GO-NAD!]

Since I don't have wide experience with many different amps, not to speak of directly comparing the sound of any side-by-side, I will just accept that even well-engineered solid state amps can sound different. However, maybe I'm not discriminating enough, as my criteria for choosing an amplifier would be sufficient power for my needs, reliability, and price. I might give the distortion specs a glance, but if the amp is competently engineered, I wouldn't be too OCD about distortion, as I would think loudspeaker quality and room acoustics would be of far greater importance. Am I wrong?

 

[bogrod]

Oh, no, those $200K amps most definitely sound better. I don't care what anybody says. They are just simply jealous.

I'm wondering though if you'd put that perspective on the line in a true DBT

 

[Irvrobinson]

I'm wondering though if you'd put that perspective on the line in a true DBT

Audio DBTs are a waste of time, IMO. Audio memory is terrible WRT to subtlety. Personally, I find blinded audio comparison tests to be tedious and annoying.

 

[PENG]

Audio DBTs are a waste of time, IMO. Audio memory is terrible WRT to subtlety. Personally, I find blinded audio comparison tests to be tedious and annoying.

Well you said personally and I can see that for sure. For those who are interested in what the test results could mean, it is not a waste of time. I don't think those tests could conclusively say one thing or another, but I do think if we cannot pick out the right one consistently then the differences between the test objects will not be too significant or as you may call it, "subtlety". I am guessing we are on the same page.

 

[Irvrobinson]

Well you said personally and I can see that for sure. For those who are interested in what the test results could mean, it is not a waste of time. I don't think those tests could conclusively say one thing or another, but I do think if we cannot pick out the right one consistently then the differences between the test objects will not be too significant or as you may call it, "subtlety". I am guessing we are on the same page.

Actually, I think DBTs mask audio differences. There, I said it.

 

[AcuDefTechGuy]

I'm wondering though if you'd put that perspective on the line in a true DBT

No, I would not wager or put it on the line because I could easily lose.

 

[AcuDefTechGuy]

I definitely believe in DBT in regards to drug research.

But I really don't care either way when it comes to subjective impressions in any hobby.

I don't have an issue with anyone believing that one amp sounds better than another amp. People can believe whatever they want because they're not killing anybody, unlike drug and medical research.

 

[Irvrobinson]

I definitely believe in DBT in regards to drug research.

But I really don't care either way when it comes to subjective impressions in any hobby.

I don't have an issue with anyone believing that one amp sounds better than another amp. People can believe whatever they want because they're not killing anybody, unlike drug and medical research.

I was very specifically calling out audio, as in relying on human audio memory to identify subtle differences. I wouldn't want drugs that weren't DBT tested either.

 

[RichB]

I don't have an issue with anyone believing that one amp sounds better than another amp. People can believe whatever they want because they're not killing anybody, unlike drug and medical research.

That's the beauty of forums. If some folks were in the same room, I am not so sure

- Rich

 

[3db]

Actually, I think DBTs mask audio differences. There, I said it.

I don't understand the value of DBT either.... as long as the listener cannot see what is being evaluated and the person controlling the listening tests doesn't have a dog on the race. I would prefer the SBT test. Done right, blind listening tests should prevent serious engagement of auditory memory with all of its flaws.

 

[PENG]

Actually, I think DBTs mask audio differences. There, I said it.

I have heard products of 7 of the listed brands so I know DBT can easily mask the audio differences among them. Base on subjective memory, I prefer the Bryston's sound but still don't find it sound much different than my Adcom 555 (the one you reject on sound quality). Even on sighted comparison, I thought the Bryston sounded a little different than the Halo. It was done with someone who has better hearing than me and he prefers the Bryston but again he wasn't sure if he could tell the difference in a BT, when asked, he said "I don't know, I think so". So there, I don't believe the listed amp would sound different enough in even SBTs but yes they would sound different, differently good too. Oh, I don't remember if I posted the REW graphs I took comparing 2 of my amps and the Denon 3805 that show all 3 look almost identical and all have very low THDs. Now I am not saying that is proof for anything other than they all seem accurate enough on paper. The graphs for the pre-amps told a different story.

By the way, I know many people think Brystons look ugly. Well, it grows on me, I now prefer them to the Mc amps. The Halo amps look great on the front but ugly if you have a full view of the heat sinks. I am beginning to find the Mcs look too busy and too distracting for serious classical music enjoyment. Their power amps with the large VUs still look the best to me though.

 

[PENG]

I don't understand the value of DBT either.... as long as the listener cannot see what is being evaluated and the person controlling the listening tests doesn't have a dog on the race. I would prefer the SBT test. Done right, blind listening tests should not prevent serious engagement of auditory memory with all of its flaws.

I have done enough SBTs to agree with you.

 

[AcuDefTechGuy]

I was very specifically calling out audio, as in relying on human audio memory to identify subtle differences. I wouldn't want drugs that weren't DBT tested either.

Yes, I knew that. I was kind of reinforcing your opinion of audio research.

 

[AcuDefTechGuy]

That's the beauty of forums. If some folks were in the same room, I am not so sure

- Rich

I think on the contrary. If people were in the same room, it would be a bunch of guys disagreeing amicably. When we see each other face to face, I think it's less likely that we would fight over something as trivial. It's sort of (but not exactly) like disagreeing on which foods or drinks taste better.

I wouldn't care about any DBT on foods and drinks.

 

[AcuDefTechGuy]

I have heard products of 7 of the listed brands so I know DBT can easily mask the audio differences among them. Base on subjective memory, I prefer the Bryston's sound but still don't find it sound much different than my Adcom 555 (the one you reject on sound quality). Even on sighted comparison, I thought the Bryston sounded a little different than the Halo. It was done with someone who has better hearing than me and he prefers the Bryston but again he wasn't sure if he could tell the difference in a BT, when asked, he said "I don't know, I think so". So there, I don't believe the listed amp would sound different enough in even SBTs but yes they would sound different, differently good too. Oh, I don't remember if I posted the REW graphs I took comparing 2 of my amps and the Denon 3805 that show all 3 look almost identical and all have very low THDs. Now I am not saying that is proof for anything other than they all seem accurate enough on paper. The graphs for the pre-amps told a different story.

By the way, I know many people think Brystons look ugly. Well, it grows on me, I now prefer them to the Mc amps. The Halo amps look great on the front but ugly if you have a full view of the heat sinks. I am beginning to find the Mcs look too busy and too distracting for serious classical music enjoyment. Their power amps with the large VUs still look the best to me though.

I wouldn't even be willing to bet my $1 on an amp DBT between a $200K amp vs a $1K amp. Anything is possible. I don't like losing, not even $1.

 

[Hobbit]

I was very specifically calling out audio, as in relying on human audio memory to identify subtle differences. I wouldn't want drugs that weren't DBT tested either.

I often find when I try something new that I'm not used to, I'll seem to prefer it. This happens for subjective tastes from food to sound. I recently bought a Fender Mustang III modeling guitar amp. I change to a new sound and I love it for a while. Eventually it grows old and I end up back to my "normal" tone. Kind of like the first few dates with a new girl you're hitting it off with. Everything is new, fun, and exciting....