This is based on R. G. Keen’s LoFi telephone noise maker/emulator modified as a variable bandpass filter with the noise component removed (a mod suggested by M. Hammer). I updated the original schematic (by Keen) with the mods.
And I did a quick vero layout as well. I’ve already built this and it works, so this is verified.
I wouldn’t know about the best place, as there are many different options, some more elaborate than others. The easiest way would probably be to replace R15 with a potentiometer and take the output signal from the wiper/center lug. 1M pot would be a direct replacement, but a 100k probably work well too.
Best place for an output volume control? Pot value for such a control?
These are dual pots where one shaft rotates two pots at the same time (-not- two separate shafts, one within the other).
Example: http://smallbear-electronics.mybigcommerce.com/alpha-dual-gang-16mm-solder-terminals-linear-audio/
Hi, Harald. Just wondering, are the pots here dual-gang?