[bigshot]

Well, if two amps sound different, it's a pretty safe bet that at least one of them is wrong.
 
There are better ways to color sound than to have it randomly hard wired into your amp.

 

[i019791]

It would be helpful if you could name three different accurate headphone amps.

 

[castleofargh]

it's not about finding 3. most amps are in fact audibly transparent when used as intended.
then it's about impedance output and what they can drive best. some lose linearity with low impedance headphones, others distort when they have to output too much voltage...

 

[ab initio]

  it's not about finding 3. most amps are in fact audibly transparent when used as intended.
then it's about impedance output and what they can drive best. some lose linearity with low impedance headphones, others distort when they have to output too much voltage...

... and some sensitive headphones make the background hiss audible on high gain amps... etc., etc., etc...

  Well, if two amps sound different, it's a pretty safe bet that at least one of them is wrong.
 
There are better ways to color sound than to have it randomly hard wired into your amp.

I think if you replace "wrong" with "inaccurate" you will be less likely to offend the folks who are emotionally attached to the gear that they've purchased. Also, I disagree with your statement "if two amps sound different, it's a pretty safe bet that at least one of them is [inaccurate]," because if two amps sound different, then there is absolute certainty that at least one of them is [inaccurate]. I don't think its fair to leave any doubt about the absolute certainty of it because it might confuse others.
 
Cheers

 

[bigshot]

I have two headphone amps... an Oppo HA-1 and an Altoid tin cmoy. They are both accurate.

 

[i019791]

How do you know that a more accurate amp does not exist ?

 

[castleofargh]

  How do you know that a more accurate amp does not exist ?

that's the end point of most of the discussions in here.
some gears get closer to perfectly accurate(never reaching it), but as our hearing is very far from perfect. when the difference between perfect accuracy and what the amp outputs is smaller than the smallest difference our ears can notice, then to us it will sound just like perfect accuracy. just like 2 side by side points become one as soon as you're far enough. then going further away doesn't make it more just one point. the same way 2 gears will sound the same when the difference is smaller than what we can hear.
in effect this makes everything in a range between our limit of perception and real perfection, to sound absolutely identical. so more accurate just sounds accurate(not more, not less), and something sounding differently cannot be accurate.
 
so what we maybe mistakenly call an accurate amp, is in fact anything that will sound the same as accurate to a human being.

 

[nick_charles]

  I have two headphone amps... an Oppo HA-1 and an Altoid tin cmoy. They are both accurate.

 
I'm not saying you are wrong, but how do you know that they are accurate ?

 

[bigshot]

Elementary, my dear Watson! They are identical, and both are identical to the headphone out of my phone, iPods and Macs. The odds that all of them would be inaccurate in exactly the same way are pretty slim.

 

[bigshot]

  How do you know that a more accurate amp does not exist ?

 
More accurate than humans can hear perhaps. But I really don't buy stereo equipment to please bats.

 

[i019791]

Fine in theory.
I am still missing the evidence that there is nothing "more accurate to human being" than Oppo HA-1 or Altoid tin cmoy.
Without evidence, any two amps sounding the same (even bad comparatively to a third amp) could serve as the benchmark for accuracy.

 

[bigshot]

Bad design usually creates random error. If every amp sounded different, it could be chalked up to bad design. But when a dozen or so different components all sound exactly the same, it can probably be attributed to proper calibration. Most manufacturers aspire to making audibly transparent amps. They usually succeed. It really isn't that hard to create a clean flat amp.
 
But feel free to wait for whatever evidence supports your pet theory. All I care about is getting accurate sound.

 

[KamijoIsMyHero]

  I once had simultaneously the Audio GD NFB-12 and Audio GD NFB-10SE, both feeded lossless music from the same laptop to AKG K701 headphones.. Both me & my wife easily preferred the NFB-10 for what we perceived as more clear and detailed sound. Note that we compared dac+amp combos. No blind, no level match - just starting from 0 volume each time. I will not claim any checks.

 
 

  Elementary, my dear Watson! They are identical, and both are identical to the headphone out of my phone, iPods and Macs. The odds that all of them would be inaccurate in exactly the same way are pretty slim.

 
I don't see a difference in the way the 2 make claims

 

[nick_charles]

  Fine in theory.
I am still missing the evidence that there is nothing "more accurate to human being" than Oppo HA-1 or Altoid tin cmoy.
Without evidence, any two amps sounding the same (even bad comparatively to a third amp) could serve as the benchmark for accuracy.

 
This is why measurements (as opposed to specs) can be useful so that you can compare A and B doing the same thing. In another subforum the Benchmark DACs are consistently referred to as "bright" but when independently measured (and this has been done many times by different bodies) they always measure flat +/- not very much at all - where does this idea of brightness come from ? Could be listeners who cannot accurately judge flat FR, comparisons with exotic deviant rolled-off components, urban myth , who knows [/shrug]  

 

[cjl]

  Fine in theory.
I am still missing the evidence that there is nothing "more accurate to human being" than Oppo HA-1 or Altoid tin cmoy.
Without evidence, any two amps sounding the same (even bad comparatively to a third amp) could serve as the benchmark for accuracy.

I haven't seen measurements for an HA-1. Cmoys do tend to measure fairly well though (well enough for audible transparency with the majority of headphone loads, though they would struggle with truly high power demands). As for the evidence in general? Measurements are really the most reliable evidence. A properly conducted double blind study with a known good reference amp is pretty good too. Plain anecdotes like Bigshot's really aren't any better as evidence than the anecdotes to the contrary, aside from the fact that Bigshot's anecdotes are more in line with the expected results.