Integrated Amps Vs. Pre-Amp + Power-Amp

[AudioFreak]

Why is it that having the volume control in the preamp is so popular? I would have thought that a control in the Power-Amp that varies the gain of the amp rather than the amplitude of the input signal would produce a better sound output....... what i mean is that by changing the gain of the amp and not the amplitude of the input you keep the signal well above the noise floor ..... Why is this not done more often?

 

[tsz]

Probably because most amps are not stable with gain less than unity and the amount of feedback will be different for different volume levels.

/Tobbe

 

[Hedlund]

Everything changes with the amount of NFB you use.
Soundstage, musicality, stability, spectrum of distorsion etc, etc......
Even as little change as 1dB is clearly heard (if you have a small amount of NFB), and substitute the volume control with a variable NFB would need a range of approx. 0 to -64 dB.
Even if it is possible to make a working solution the sound quality would change too much with the setting to be acceptable.

Janne

 

[AudioFreak]

I am refering to amps that dont use NFB only local feedback.

 

[Hedlund]

And the difference should be ???

Besides that, you whould need a single stage with a gain of more than 1500 in order to have the possibility to have a volume range of 0 to -64dB.

Janne