G&L tone circuit question

[sixty-four]

Hey all,

I installed a JB in the bridge of my G&L Comanche that is wired exactly like the S-500. I noticed that the JB sounds extremely dark and muddy. How's that for unexpected?

I was wondering if some of the kind folks here could take a look at the PDF schematic and see if anything might be suspect. I'm wondering myself about what the C3 cap does.

Here's the schematic:

http://www.glguitars.com/schematics/S-500_schematic_blockdiagram.pdf

Thanks!

[frankencat]

That's the classic G&L bass/treble circuit. Dark and muddy huh? Maybe swap out the volume pot for a 500k. If that doesn't do it then something is either not wired correctly or there is something wrong with the pickup. Personally I like JB's with 250k pots and they are definitely not dark or muddy fwiw.

[Boris Bubbanov]

Reinstall the stock Z-coil and crank it up and see if you have hurt something thar under the hood.

Test the SD on another guitar for basic function.

I would expect the JB to work way better on a Legacy; I never considered trying one on one of my Comanches. Did you do a second pickguard, I hope?


Bubban0v

[sixty-four]

Yeah dark and muddy was definitely unexpected.

I do have the original pickguard so reversing this would be pretty simple...assuming I didn't screw anything else up in the process

I don't think it's the pickup. I haven't tried this JB in another guitar but I have tried 2 other pickups in my Comanche with the same basic results.

[tubeboy76]

Try pulling C2 out of that circuit. It looks like a treble bleed but it could darken up your buckers. Also, meter out that JB. It should read 16.4Kohms (give or take). If it reads higher than about 17K I would replace it. Also, I assume you have checked the pu height and don't have it wired with one of the phase wires instead of the hot?

[sixty-four]

Just a quick follow-up.

I checked the resistance on 2 JB's - one from my Comanche the other the stock TB-4 on my Legacy HB. Both read hot - near 18K. However, the JB in the Legacy HB didn't sound dull and lifeless. It was bright and defined.

I did yank the .001uF cap (C3 in the schematic) and that brightened up my guitar. I think that was the culprit as my Legacy HB does not have that cap in it's otherwise identical schematic.