Why amplifiers sound the same 2015-07-09 09:48:27 So I've been studying amplifier design in the last several weeks and I think I understand why amplifiers are supposed to sound the same. This is my explanation.Amplifiers amplify voltage and the load impedance, in accordance with Ohms Law, must draw a current up to the limits the amplifier can supply, which can vary if the nut holding the volume control goes overboard, so assuming the amp was operating within clean limits (not clipping) the noise and distortion can be expected to be inaudible.Solid-state amplifiers in general all seem to have similar frequency response (flat) and exhibit very low output impedance, which means they are largely load intolerant so the frequency response is likely to remain unaffected, unlike a switch-mode or valve amplifier which can affect the frequency response in very audible ways due to their high output impedance.It is well known that a change in loudness between two components can affect how one interprets the sound of that component. A small difference (1-2 dB) may lead to different sonic characteristics (enhanced dynamics, additional 'richness', 'texture', improved sound staging, speakers 'singing', etc), which is guaranteed to happen in casual comparisons.So the operating assumption is that if two amplifiers are working within clean limits (ie not clipping), with levels carefully matched to within +- 0.1 dB (a multimeter is required), in blinded conditions so that any biases from the listener (knowingly, or unknowingly) do not contaminate the listening, the amps will sound the same.This has been the default position for over 40 years supported by mountains of audibility reports in double blind testing. Now in casual comparisons, most of these assumptions are thrown out the window. Audiophiles rarely if ever compare two amplifiers in the same conditions, set up the same way. They are likely to compare two amplifiers at different volume levels, at different times, with various expectations/biases in place fostered by magazine reviews, what the salesperson said in the showroom etc.So if the goal was to 'just listen', without peeking, and assuming two amps were operating within clean limits, the expected result, as confirmed by science, is that two amplifiers will not and should not sound audibly different.Am I correct in the points I've made, or have I left anything out?