Cgs synth

>Then I wondered : why do not swap the switch and resistors by to
>potentiometers, one for amplifying, the other (passive circuit)to
>lower gain...?

Why not?

>AMP : 470 for x20, 1k for x10 and 2k2 for x5, 4k7 for x2.5...?
>ATT : 1k for x20, 2k2 for x10 and 4k7 for x5, 10k for x2.5...?
>
>So 4K7 and 10K linear pots would be okay for a x2.5/x20 gain
>excursion ?
>(Linear ? even with audio signals processed ?)

I usually use linear for everything. Log would not work when replacing the
smaller resistor. You would need reverse-log.

>I guess the 470R resistor should be keep in place (maximum gain value
>x20) as the 1K attenuating resistor, to keep a certain gain-
>relationship between the two potentiometers at position 0...

Yes, otherwise you risk driving it to distortion.

You could of course replace the other resistor (across the op-amp) with a
pot. With that resistor reduced to zero, there would be no output.

Ken
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