Another Dumb Electrical Question...

[halfwhit]

Well I've hacked apart an old LP style guitar and I'm completely re-fitting it. I've fitted the touch screen for a kaoss pad....another muse inspired mod... I'm replacing the buckers with semour duncan p90's. One tone and one volume pot. 3 way pickup switch. Theres a slow color changing LED that will be behind the touch screen. I'd like to wire it so that I don't have to flip a switch every time I plug the guitar in. Perhaps something where the act of plugging in the guitar completes the circuit for the LED. Any ideas on how i should wire this puppy?

[SwedishLuthier]

Depending on all the other electronics (check and double check so that nothing interfears with anything) a stereo jack can be used to do this. If using a stereo jack and a mono plug the tab for the ring and the tab for the sleve will be connected and can act as a switch. Thats what used for most (if not all) "active" pickup circuits.

[halfwhit]

thanks, that makes a lot of sense. i'll try that out.

next question....

could someone explain to me how pots differ? If I had a 250k volume pot in one guitar and a 1mOhm in another....how do the react differently?

[SwedishLuthier]

A volume pot works in the way that it "bleeds" the volume (current) to ground. With all pots you will actually have a slight bleed all the time as the resistance isn't infinite. With a lower volume you will have a slightly lower output (not really noticeable) and a slightly attenuated treble (really the effect of the slightly lower volume). With a higher volume pot that effect isn’t as present.