Guitar Cable Microphic after Push/Pull Volume pot installed.

Wed Nov 19, 2014 2:45 pm

I installed a 250K A Push/Pull Pot in my 03 Legacy it works and sounds great. However now the guitar cable is microphonic and it wasn’t before the change out of the volume pot.

I have tried the guitar cable in others guitars and it is not microphonic with them, Fender 98 USA Nashville, 2013 ASAT Classic S and several.

But every guitar chord I tried with the USA Legacy went microphonic when they did not do it with the other guitars.

Would anyone have an idea as to what I did wrong I have never run into this in the thirty plus years I have been working on guitars.

Re: Guitar Cable Microphic after Push/Pull Volume pot instal

Thu Nov 20, 2014 6:32 am

Instant guess:
One needs DC (charge) on the cable to make an otherwise good cable go triboelectric from flexing.
A weak solder joint might either generate DC (thermals, contact potential) or demodulate signal (incl. RF) by a nonlinearity to a tiny amount of DC. That's what I'd look for first -- you might be able to measure the DC with a good (bench-top) microvoltmeter, and fix it by resoldering. If problem persists I'd change the pot to track things down, after double-checking the circuit and any shielding efforts.

Re: Guitar Cable Microphic after Push/Pull Volume pot instal

Thu Nov 27, 2014 8:03 am

Thanks for the tip I am going to talk a look at if after the feast today.

So many projects and so little time.