What contributes most to a change in how an amplifier sounds?

@emergingsoul The secondary thing is the distortion signature of the amp, which audiophiles call the 'sonic' signature. This is in turn caused by something called the 'transfer characteristic' of the amp. The transfer characteristic has something to say about how the amp responds to transients, in particular those that overload the amp. It also says what sort of distortion will be produced, for example if based on a quadratic exponent, the 2nd harmonic or a cubic exponent, resulting in a dominant 3rd harmonic.

These two harmonics are treated by the ear much the same way in that they are innocuous. But intermodulation distortion is not and also plays an important role that is defined by the transfer function.

If you want to know more about this, read this article which starts at page 35 at the link. It might be more than you want to know, but it does answer your question correctly.

Pretty sure I nailed it on the first post.

What!?  Not the loudness button??

@atmasphere

@helomech

I love it when you guys talk harmonics. I think you guys should get together for a play date.

I think the harmonics area is underserved when people evaluate amplifiers. I like tube amplifiers because they seem to emphasize upper and lower harmonic areas that are underserved by the solid state amps.

I wish I better understood output impedance. But these days most components get along fine. Would love to hear examples where they don’t get along fine and maybe I should learn more about impedance.

Simple circuit, fewer parts and short signal path. Fewest output devices……

@toddalin  there are some speakers that are mostly resistive, such as apogee speakers. There are also many people who like the sound of SET amps.