Originally Posted by moses667
I'm very interested in learning to hear something as close as possible to a neutral baseline to help me judge what I'm hearing, both with amplifiers and headphones. How would I best go about judging a clean/neutral amplifier from one less so?
I think you got the basics bang on. An amplifier is primarily an electrical device more than the artsy sound enhancer. And any measure of performance that applies to an electrical device applies here.
This is common knowledge, there are 4 aspects of an amplifier: frequency response, gain, noise, and distortion.
So an ideal amp would be: the same gain for all frequencies, with minimal noise and distortion.
These features can help find out the more neutral and cleaner amps out there. Generally, the better the specs, the better the amp is, but whether these differences are audible is another matter.
Now, the audible properties of these specs:
Frequency response : same as headphones (bass, treble, mids etc).
Gain: Amplification (volume increase).
Noise : Most commonly heard as hissing sound.
Distortion : Can be Harmonic Distortion, or Clipping.