Chasing down noise issues...

[thechrisl]

Hi all, I recently made a couple changes to my Gretsch 5120. Years ago, I replaced the pickups with humbuckers and altered the wiring to a 50's style tone pot. It was working great & very quiet.

The most recent change was a neck pickup swap and new master volume. I like the Bourns for its fade curve. Now that I'm done, I have two issues that bother me. Keeping in mind the neck pickup is now a Phat Cat so I know it's going to be more noisy -- but this happens with the bridge pickup alone (Pearly Gates).

One, the guitar is rather noisy but gets quiet when I touch it.
Two, when I turn down either pickup volume, I get a hum.

The Bourns didn't come with a ground lug so I added one (to ground out the housing) but it didn't help much. Obviously the guitar is not shielded.

Again, I didn't notice these issues before. The "amp" I'm using (before and after) is a Kemper Profiler with the noise gates turned down. I didn't want to bring amp grounding into the mix.

Here is the schematic I'm using. One thing I'm wondering is whether I should swap the non-grounded legs on both pickup volumes. That might quiet the output when the volumes are off. Although, as I said, this was working just fine before. This kind of thing drives me nuts...

[Hsb]

Im no pickup install expert but sounds like there is a ground issue. Id say recheck your solder joints. The its noisy till I touch it sounds like a ground issue to me.I could be far off base with that thought though.

[thechrisl]

Yes I'm sure it is a grounding issue. It's always a grounding issue and grounding issues are the worst... I've checked resistance between all the grounded components & it's less than 1 ohm.

Checking solder joints on a hollowbody is a major pain (due to the disassembly) & I don't think I've ever experienced a bad solder joint but I suppose I can try that. I just wondered if it was something else I'm not seeing. For example, the Phat Cat has a bare braided shield. From prior use, the cable isn't long enough to reach so it's spliced mid-way to the harness wire (which is all "coax" style as well -- like an RCA cable). Everything shown in the schematic is grounded via that outer shield in the harness cable.

But again, I have issues whether the PC is switched on or not.

[thechrisl]

Bumping for more input. Maybe just focus on the question about swapping leads if you don't want to talk about ground issues.

[Bowtomecha]

Should that master volume be wired that way? Maybe you should switch the in and out leads.

Also maybe switch to a one meg master volume? It won’t help with the noise but it looks like the circuit is loading down.

[IMENATOR]

Is the bottom of pots properly grounded? Check continuity among every single point that should be connected to ground. If there is any

[IMENATOR]

Is the bottom of pots properly grounded? Check continuity among every single point that should be connected to ground. If there is any "bad looking" solder joint it may be worth redoing it. After 10 years or something my blue strat's ground connection to the bridge claw came off because of rust, it was a cold solder joint. This guitar always had a bit more noise than the others, now I see why.

[JB_From_Hell]

A cold solder joint is when one part didn’t get heated properly. Corrosion won’t cause that.

Don’t discount your home’s wiring. I’ve never used a Kemper, but even though it’s not an amp, it’s still amplifying a signal, and seems it could be susceptible to house wiring issues. My guitar room is across from our laundry room, and if the dehumidifier or dryer is on, my stuff tends to be noisier than if they’re not.