sunking: Gain mod ?

[Ang3lus]

subbing the dual gain pot for a 250k will yield higher gain right ?

can i just add 100k or 150k resistors to the pot that's inside the enclosure now ?

do i add them to both levels of the pots and to which legs ? 1 and 3 ?

[stecykmi]

The sunking uses an unusual topology that I don't quite understand, particularly the GAIN2 (in reference to MB's schem).

GAIN1 seems to control a biasing circuit rather than a feedback circuit. If you increased R9, it should increase the gain since it will decrease the feedback. Using a larger pot will also work.

As for GAIN2, I think the control balances feedback from the R16/R17/R18. The feedback is divided between the IC1A/filter network and VB(which acts as an AC ground). A larger value for the pot may not necessarily increase the gain here... I think a resistor connected to lug 1 or 2 of the pot will increase gain since that limits feedback. I think lug 2 might be better since it would interfere less with the filter network.

That's my brief analysis and I may no claims of correctness. Your best bet is to experiment.

[stecykmi]

Actually, on second thought, a larger pot value for GAIN2 would increase the gain, but so would a resistor at lug 1 or 2.

[madbean]

You can increase R11 to 680k or 1M.
Or, you could lower R10 to 6k8. If you do that, increase C7 to 150n to keep approximately the same frequency response.