Hello. I am hoping to make a synthesizer module out of Bleeplab's Picopaso device (see schematic below). I have previously built the device from a kit (which are no longer available), discarding the 9v battery case and powering the LM324N with with a single supply +12v wallwart (pin 11 to ground). My question is this: Would changing this to dual voltage simply be a matter of powering the LM324N with +12v and -12v (and grounding the rest of the circuit elsewhere) and changing the ground on the "Shape" pot pin 1 from ground to -12v?

 

Hi,

I'm curious as to why you would like to change it to +- supply when the LM324 can work off a single supply.

Does "Any rail-to-rail op amp should work. I prefer...") mean input, output, or both? (Just in case, remember the 324 input can go rail-to-rail but the output can only go to supply voltage minus 1.5V).

I'm not sure but I suspect the answer is yes to the trimpot but no to the vague/fuzzy-sounding "...elsewhere". Might find a simulation will save a lot of second-guessing and irritating surprises, and the 324 is a very standard, well-modelled (Spice family of simulation tools) part. Where would the squarewave signals be centred - around 0V with +-12V amplitude?

Simulate it and see.