Originally Posted by TMRaven
There's a flaw in the argument of 'this amp simply increases the volume of the headphone and thus is working fine.'
How do you absolutely know how the headphone is supposed to sound in the first place? Everything is relative in this hobby, there are no absolutes. You can only compare the E17 to the O2. You can't just say the O2 simply raises the volume without altering the sound while the E17 colors it. You also simply can't throw out measurements of ruler flat frequency responses and THD numbers well below the hearing threshold, because almost every amp has measurements like that, yet they sound different.
There are absolutes, and also standards, tolerances, and 'industry best practices'. Only marketers believe in infinite 'relativity'. I believe in a certain 'individuality' in listening preferences and so on, but don't bother myself believing that any speaker should have a known sound quality beforehand. I do know that 'flatter' usually = better sound no matter what I am listening to. So that is one 'spec' I look for. A little different for phones' but I am just making a point.
The first issue with an E17 and O2 comparison is the former is a DAC/Amp, while the latter is just an amp. An amp is an intermediary in the signal chain, not a source or an endpoint. A good amp can be made to sound bad given some conditions, but no bad amp can be made to sound good. The O2/ODAC is the only amp setup I've ever owned that is totally black, high gain or not. If you've owned bad amps, you should be pissed and frustrated about the noise / sound quality issues that cannot be helped. That will never be musical to me. You wouldn't play a guitar with missing strings would you? Likewise all amps might 'sound different' because of differences in power, THD, output impedance, and so on. There are factors that can influence performance that may or may not be perceptible. I do believe in 'warm' and 'cold' sound, but that is about it.
The second issue is asserting that all amps 'measure well' but still 'sound different'. That would be sort of like claiming that 'all republicans are the same' and then adding that 'none agree on anything'. It is grouping based on a narrow distinction but followed by a statement that undermines the original position. Either something is the same or it is not, and if not, the differences need to be explained. Given that they are likely subjective, only blind testing could determine if the difference were real or percieved. Since people trust their senses (I don't), they hate being proven wrong! To defuse anger, I would suggest you stage a blind test of certain foods. Lots of people think they have a refined palate, but would flunk a taste test of apples, wine, or whatever. You only think you know.