Audio amplifiers?

[capitano]

Is there any reason why an op-amp amplifier would not be as
good as a dedicated audio amplifier. I.e. why do people spend
time designing audio amplifiers (or pre-amplifiers) where a simple
op-amp and 3 or 4 resistors could act as an amplifier ?

 

[Bob]

"capitano" <sdfsdf@Fsdfsdf.sfdsdf> wrote in message
news:bfsaa30kia@enews4.newsguy.com...

Is there any reason why an op-amp amplifier would not be as
good as a dedicated audio amplifier. I.e. why do people spend
time designing audio amplifiers (or pre-amplifiers) where a simple
op-amp and 3 or 4 resistors could act as an amplifier ?

In a nutshell, the custom-designed amplifiers (usually comprised of discrete
active devices) are believed to be more accurate for the reproduction of
complex signals, like music.

The goal in hi-fi amp design is create a circuit which has intrinsically low
open-loop gain and distortion, and then uses minimal (or no) loop feedback
to obtain the required performance and/or specs. Opamps have extremely high
open loop gain, so with low closed loop gain then the amplifier is
constantly correcting itself to reproduce the input signal with the desired
closed-loop gain.

Whether or not a non-opamp amp really sounds any better than one that uses
opamps is a matter of debate, conjecture, opinion, psychology, profit
margin, etc...

Bob