Can you hear a difference in Sound between Audio Amplifiers?

[AcuDefTechGuy]

Of course all amps sound differently - as long as they are all setup/connected to different speakers, subwoofers, and rooms.

 

[RichB]

Of course all amps sound differently - as long as they are all setup/connected to different speakers, subwoofers, and rooms.

Amps sound differently when they clip or fail to drive a difficult load.
Some amps come close to the one percent distortion level when driven less than a watt.
Within that those THD measurement it can be odd harmonics or perhaps it is just the influence of the noise floor.
I am not sure when these become audible.

Since I spend a great deal of tie listening to music ad pies in the 70 db range, this may be an important performance characteristic.

Hometheater mag and other reviews often show curves where THD rises fairly high at the low end.
Emotiva used to show below 1 watt. The XPA version 2 amps are not measured below one watt. Interesting.

My Parasound a51 measures better than my Outlaw 7500 and generally better than Emotiva's.
However the Emotiva XPR-1 measurs better than them all.

- Rich

 

[Irvrobinson]

Hometheater mag and other reviews often show curves where THD rises fairly high at the low end.
Emotiva used to show below 1 watt. The XPA version 2 amps are not measured below one watt. Interesting.

That's because the graphs you're looking at are THD + noise, and the y-axis is in percent. Noise is actually a certain voltage level that occurs over a given measured spectrum, and so as the output voltage goes down the percentage that noise makes up of the total output goes up. Also, the measuring equipment typically has lower resolution limits of about -130db, which can affect measurements down in the 1/100th watt range.

Frankly, I don't like old-fashioned THD+N graphs, and prefer the FFT analysis graphs AH does. There's so much more information in the FFT charts.

 

[PENG]

Some amps come close to the one percent distortion level when driven less than a watt.
Within that those THD measurement it can be odd harmonics or perhaps it is just the influence of the noise floor.
I am not sure when these become audible.

Since I spend a great deal of tie listening to music ad pies in the 70 db range, this may be an important performance characteristic.

Hometheater mag and other reviews often show curves where THD rises fairly high at the low end.
Emotiva used to show below 1 watt. The XPA version 2 amps are not measured below one watt. Interesting.

My Parasound a51 measures better than my Outlaw 7500 and generally better than Emotiva's.
However the Emotiva XPR-1 measurs better than them all.

- Rich

I wonder which amps would come close to 1% at below a watt? I also spend most of my time listening to less than 1W so I really want to know how my amps behave at such low level. Unfortunately I am unable to find THD figures at fractional watt levels. At 1W to 20W, from what i could find, even my oldest AVR-3805 could do better than 0.01%. The A21 in facts was tested very good at between 1& 10W and the Bryston 2B SST2 was even better. We are talking 0.001 vs 0.003% so I doubt they are audibly different though.

It seems to me THD+N is likely not the reason why amps sound different if (only if) we can assume most power amps can do better than mid range AVRs, unless we are comparing amps that has close to or higher than 1% THD+N at the below 1W level, but again, which amps do that?

 

[RichB]

Check out this review of the Sherbourn amp.
The powe versus THD+N.a. The degree to which the red line climbs the wall. It links like .9%.

Here is the Marantz MM8807 which climbs to not .06:

Marantz AV8801 Surround Processor & MM8077 Amplifier HT Labs Measures | Home Theater

Here is the Parasound a51 at .3:

Parasound Halo P 7 Multichannel Preamplifier, A 51 Multichannel Amplifier & JC 1 Single-Channel Amplifier HT Labs Measures | Home Theater

I am not sure what the methodology is but the results clearly vary.
It is bot 1 watt that is a problem, but I wonder what happens below where I spend the majority of my listening.

- Rich

 

[PENG]

I am not sure what the methodology is but the results clearly vary.
It is bot 1 watt that is a problem, but I wonder what happens below where I spend the majority of my listening.

- Rich

That's exactly what I am wondering too, but I could only find data for 1W but not from 0 to 1W. The HTM graph does plot to 0 but like you say we don't know what methodology and the resolution is so poor we have to guess what it is at say 0.2W as it could be 0.02% and that wouldn't sound bad. Also, it could be the noise that pushes the figure higher towards the original of the x-axis. I may email them about it.

I guess to play it safe we have to start listening a little louder, try to stay above 0.25W most of the time. I think I may end up getting that Luxman 25W amp if they would disclose their 0 to 1W distortions specs.

 

[jeff1956]

Wow the poll results are interesting so far. It tells me you guys need to do a little more listening and not so much overthinking

As someone who has over 10 years of audio design experience and about 15 years measuring and analyzing and most importantly LISTENING, I can tell you my experience even in controlled listening tests is amps can and do sound different even if they measure well and aren't driven beyond their means. The degree of audibility differences depend on a lot of factors, including loudspeaker load, quality of the loudspeakers, room acoustics, source material, etc. I think I may need to host a little amp face-off at my place between the Pass Labs, Classe and Emotiva amps. Could be fun (especially if there is ample supply of alcohol involved),despite the amount of work involved.

I would love to see the results of Amp face off.
You should include a very good D-class amplifier also

To me the difference's are the least noticeable of the major components
Speaker-most noticeable
PreAmp-Dac -2nd on list
CD player/Itunes vs Ammarra etc-3rd on list
Amplifiers-bottom of list- least noticeable..

Jeff 1956

 

[krabapple]

Did it (the Amp face off using correct level matching and DBT) ever happen?

Oh, wait, never mind. I see Gene Della Salla et al. are still classifying me as 'a forum troll idiot that just begs for attention'

This was explained to me back in April (when I was told it would be fixed) as "It's possible you rubbed one of our forum mods the wrong way and he went postal on you."

Watch out for those postal mods. Maybe they need more coffee breaks.

 

[LAB3]

I posted on this thread awhile back that I did think a different amp would sound different.....well I can hear a difference in amps. I hooked up a Hafler P3000 Pro Series MOSFET amp to my HD AVR and played a CD in 2 channel stereo......... my speakers sound better with more bass at lower volumes with the amp hooked up to the fronts.

 

[BoredSysAdmin]

OP's starter - Admin Banned??

 

[Steve81]

Did it (the Amp face off using correct level matching and DBT) ever happen?

Not that I'm aware of.

Oh, wait, never mind. I see Gene Della Salla et al. are still classifying me as 'a forum troll idiot that just begs for attention'

This was explained to me back in April (when I was told it would be fixed) as "It's possible you rubbed one of our forum mods the wrong way and he went postal on you."

Watch out for those postal mods. Maybe they need more coffee breaks.

Not necessarily a mod. That's a function of the "add to this user's reputation" feature, or deduct as the case may be. It's the little star next to the "Thanks" icon. Any user with a positive reputation score can show their appreciation to another by adding reputation points. Conversely, if you've ticked somebody off who happens to have a high reputation score, they can deduct from your reputation to the point where you earn that moniker. If you're not fond of being labelled a forum troll idiot, my advice would simply be to try and play nicely.

 

[krabapple]

Not that I'm aware of.
Not necessarily a mod. That's a function of the "add to this user's reputation" feature, or deduct as the case may be. It's the little star next to the "Thanks" icon. Any user with a positive reputation score can show their appreciation to another by adding reputation points. Conversely, if you've ticked somebody off who happens to have a high reputation score, they can deduct from your reputation to the point where you earn that moniker. If you're not fond of being labelled a forum troll idiot, my advice would simply be to try and play nicely.

Gee, thanks, but I know how rep points work. Someone managed to give me -19,0000 in a very short period of time.

It was Gene himself who suggested to me it was a mod gone postal...and who agreed it was a bit OTT. Do you know whether and how I failed to 'play nicely' or are you just assuming I did?

 

[krabapple]

I posted on this thread awhile back that I did think a different amp would sound different.....well I can hear a difference in amps. I hooked up a Hafler P3000 Pro Series MOSFET amp to my HD AVR and played a CD in 2 channel stereo......... my speakers sound better with more bass at lower volumes with the amp hooked up to the fronts.

This thread contains some excellent explanations why two amps compared this way might sound different. And suggestions for comparing them a more reliable way.

 

[Steve81]

Gee, thanks, but I know how rep points work.

Then you should know full well that some posters can accomplish the feat of giving you -19,000 rep points fairly quickly, particularly if they've got a friend or two helping them.

It was Gene himself who suggested to me it was a mod gone postal

It's possible. However, if I were to "go postal" on you, it'd involve a ban, not rep points.

Do you know whether and how I failed to 'play nicely' or are you just assuming I did?

Given your current demeanor, it's not much of a stretch for me to imagine that you've rubbed others the wrong way.

 

[LAB3]

Gee, thanks, but I know how rep points work. Someone managed to give me -19,0000 in a very short period of time.

It was Gene himself who suggested to me it was a mod gone postal...and who agreed it was a bit OTT. Do you know whether and how I failed to 'play nicely' or are you just assuming I did?

Where are these points at? I was not aware of this as there have been several members that have been rude to me in the last few years that I just hit the ignore function on.
I try NOT to argue with members that differ from my opinion anymore. On the amps etc section there is a lot of doom and gloom going on with the future of Denon and Marantz now that D&M has been purchased. I heard the same thing when Klipsch was purchased LOL.

I found the point count. Hey you were nice to me

 

[RichB]

I don't think all amps sound that same, but I am pretty sure all amp "sound" threads might

- Rich

 

[AcuDefTechGuy]

I don't think all amps sound that same, but I am pretty sure all amp "sound" threads might

- Rich

A lot of high quality amps sound equally fantastic even if they don't sound the same.

 

[herbu]

A lot of high quality amps sound equally fantastic even if they don't sound the same.

I'd put picking a high quality amp in the same category as picking high quality speakers. You likely can't do comparisons in your home. Read the reviews, pick the features you like, from a company the industry respects, buy and enjoy.

 

[AcuDefTechGuy]

I'd put picking a high quality amp in the same category as picking high quality speakers. You likely can't do comparisons in your home. Read the reviews, pick the features you like, from a company the industry respects, buy and enjoy.

Yeah, if you spend $10K on speakers (or similar MSRP), you might as well spend some money on amps and everything else, as long as it is still reasonable and not $30K amps.

 

[RichB]

I'd put picking a high quality amp in the same category as picking high quality speakers. You likely can't do comparisons in your home. Read the reviews, pick the features you like, from a company the industry respects, buy and enjoy.

Totally agree.
I think when you get to the lower end there can be difference that may not be evident when examining the specs and standard distortion measurements.

For example, in listening session at my brother-in-laws, we listened to Outlaw M2200 mono-blocks (200 WPC) and my Parasound A51 (250 WPC) there was a clear different at mid 90 BD levels. A BDP-105 directly connected to the amps driving his Revel F206's. At lower levels (about 55) the M2200 was fine, but at 75, the M2202 became harsh. The M2200 is A/B for about 70 watts and then goes into G mode.

I doubt we would hear a difference between an amp like an ATI3000 and the A51 driving the Revel F206's.

There were really good deals on the A21 so he bought one.

- Rich