Hi all,
Last weekend I've rewired my Gretch Electromatic Bo Diddley guitar as I personally don't really like the standard Gretsch controls of 1x volume per pup, 1x master volume and 1x master tone.
I wanted to try something like this:
* signal from each pickup into its own Fender TBX tone control
* the two pickup signals into a dual gang pot wired for 'stereo' volume panning (intended here as a single control that can cut either pickup level and does nothing at center detent)
* the two outputs from the volume panning pot to the 3 way switch
* the single output from the switch to the master volume and then to jack
I know this description is a bad substitute for a schematic, but it roughly shows the idea for the signal path. All grounds were connected and I didn't forget about grounding the strings etc through the bridge.
The only wiring I actually had to change were the TBX and volume pan pots. The volume pan pot output lugs I then connected to the leads that go to the toggle. The wiring of the toggle and the master volume I left as it came from the factory.
Now, upon testing it, the two TBX tone controls and the one pickup pan control worked as expected. The master volume did not. Well, it does reduce the volume when turned down, but doing so also gradually brings up a hum / noise, which becomes quite loud when the master volume is turned all the way down. As it stands, the only way to make the guitar quiet is to set the master volume at 10 and mute the strings. When playing it with the volume fully up, it doesn't sound bad in any way. Only turning the master volume down causes trouble.
I don't know a lot about electronics (obviously), but I suspect a ground issue. So I have checked with my multimeter that the back (ground) of all controls has zero resistance to the jack ground. Did the same for the bridge, strings, etc. This all looks fine, no bad solder joints or broken leads as far as I could tell. But still the noise problem remains. Also, the problem is unchanged when I flip the toggle, turn the TBX's or the pickup volume pan pots into different positions, etc. The noise seems related only to my master volume control.
I've searched both the forum and the interwebs but my issue seems to be a rare one. At this point, I am stumped.
Does anyone have suggestions as to what may be going on or how to debug this?
Thanks!