In article , Andy Evans wrote:
Don't anyone ever tell me all good amps sound the same, they simply don't,

Yes, they do

Another vote for "they simply don't" here. As we should have expected, opinions
are completely divided.

I wonder if you or someone else could explain why they don't (or why
they shouldn't)?

As background this is my perspective:

* As a former engineer (who has designed and built audio amplifiers in
an amateur capacity), I design an "amplifier" to amplify. For the range
of expected loads and the range of expected output voltages, the output
voltage differs from the input only in amplitude (usually with a small
delay - 1.5 microseconds or so).

* Loudspeakers and rooms are still so variable that adding one more
variable is not a good idea if reasonable accuracy - "high fidelity"
- is a goal. My goal *is* high fidelity to the recording and not to
make the recording more euphonic by using the amplifier. As such I
believe the amplifier should be "transparent" and that translates into
the goals above.

* If the load (the loudspeaker's impedance) is outside the design limit
or the amplifier is asked to produce a greater output than specified
then I am sure the amplifier could have its own sound but that's an
abnormal operating condition.

The logical outcome of the above principles is clearly (to me) that an
amplifier that is properly designed and is operating within its limits
cannot have its own sound. Thus "all good amplifiers sound the same."

Of course it could be argued that for the current state of the art or
for a specific budget the above goals cannot be achieved. However I
assume at least the state of the art is sufficient leaving only budget
as a possible consideration. It could also be argued that the above
goals are not shared by everyone.

--
John Phillips