Worth a shot: Any guitar techs here?

I have a massive problem with one of my guitars. All of them have “exotic” wiring but this one is being a white hot bitch.

It has a massive, massive buzz. Not 60Hz buzz.

Telecaster
2 SD Humbuckers - 4 wire
4 DPDT push pots
Neck and Bridge volume coil splits
Neck Tone = Parallel/Series
Bridge Tone = Out of Phase switch (only on middle postion on PUP selector)


I have it star grounded with 18g solid copper wire. No solder bridges. Wired properly as shown (although this drawing neglects grounding all of the pots together, which I did):



Buzz is awful. DOESNT CHANGE WHEN VOLUME IS ADJUSTED. Both PUPs. Goes away entirely when I touch a metal part.

Cable is good and amp is good. All of my other rigs have zero buzz.


Everything functions

I had this exact same problem with the bass that Brewmeister traded me here last year. It was one of the pots, grounded incorrectly. It was a $35 fix at a local guitar shop.

I guess that is like the “make sure your computer is plugged into the wall” answer here though.

Yeah, remember that electronics is a very specific area of expertise with me but this has me all fucked up. It makes no sense.

I tested the pups and they’re good. It has to be a bad pot. Only thing I can imagine wrong at this point. The thing is that they’re all grounded to a common point. So, unless there’s a pot that’s not grounded to itself internally or something I can’t imagine what it is.

Buzz like that is a guaranteed ground problem.

It's routing around the volume like you said, and when you touch something it grounds through you (and stops buzzing).

Is the interior cavity shielded? Is that connected to ground?

These are probably dumbass questions for you, but check them anyway. Otherwise, get the multimeter and start digging.

Pete, I'll echo the same sentiments expressed here. It's a ground. Can you take the pots out of the chain and put them back in one at a time? That will find the offender. It's odd because pots don't usually just crap out.

I’m positive that it has to be ground - this particular rig isn’t shielded. That’s step 1: faraday cage in the cavity. That made my Strat “Gilmour silent” so if it’s EMI, that will sort it.

Step 2, assuming shielding doesn’t work, is going to be rewiring it with new Bourne pots and new capacitors. I can’t imagine the pots being killed from heat, but it’s possible. In any event, I will just have to suck it up. I’m going to use strand wire instead of the solid copper 18ga wire I used. Makes things more resistant to bending and vibration.

This is just a total bitch.

Your guitar has a tough wiring setup with the push-pull pots. I don't personally enjoy wiring guitars. I like to just buy them and play. Good luck, dude.

I love to wire them and tweak them. It's the engineer in me. I remember back when I did shit like this for a living....it reminds me that I wasn't always a fucking buyer.

The push pulls aren't as hard as you think. It's the crossovers that's hard.

I can't help you, because my electrical knowledge of the insides of my guitars is limited to "this knob makes it sound louder"

Good luck mate, my guitar tech has spent 4 months trying to figure out where the buzz is coming from on my peavey - I have a dual humbucker set up in neck and bridge with a single coil mid - three toggles - i can split either humbucker and then have any combo of the three pickups. No buzz when using neck and bridge together or bridge and neck or bridge and mid - all three bzzz, bridge position alone bzzzz, neck alone bzzzzz, mids fine on it;s own. We've rebuilt the cage, replaced pots - He's still fiddling with it.

SuperflyTNT wrote: I love to wire them and tweak them. It's the engineer in me. I remember back when I did shit like this for a living....it reminds me that I wasn't always a fucking buyer.

The push pulls aren't as hard as you think. It's the crossovers that's hard.

I'm the same way. My old strat copy has it's own wonky wiring system, based on what I thought I wanted from it. I swapped phase on the middle pickup and rearranged the 5-way from the usual

N-NM-M-MB-B setup to

M-NM*-N-NB-B

so I can still get each individual pickup, but also a neck/bridge mix and neck/middle out-of-phase, which gives me a lovely "distant" sound when I use that setting.

I think you've got more than just EMI going on there, I think you're failing to ground somewhere. The "buzz stops when I touch it" is the kicker to me.

You’ll note in the above drawing that the pots aren’t “single point grounded” - there’s no pot grounds to the main. I added them.

I think the wiring produces a ground loop. The more I look at it the more I have no idea how the fuck this is supposed to work. Mostly because I don’t know what lines come from the 4 wire pups.

You should hear my Strat. It’s fucking wicked. Vintage middle and bridge pups and a Texas Special in the neck. Wired with a blender.

Since you've got so much splitting going on there, not everything is going to be directly grounded. The volume pots have those bent over pins to ground their case, but then they're going to ground through the other pots. I wish I had a better resolution diagram. What would probably help there is to redraw it with the push/pull crossovers split out (as a switch, which they really are), then compare that logical diagram to what you built. In that tiny phone shot, it's hard to tell exactly what's up.

I can see the coil splits on the top, but it's also mixed up with the phase trickery (the crossing in the lower left). That's why you've got totally different color code hookups between the two.

Extra grounds would worry me, as I can see the path, especially on the neck volume which isn't ever switching phase.

Also, charge your damn phone.

www.allparts.com/EP-4144-000-Wiring-Kit-...-Paulreg_p_4447.html

I have a warrant for my arrest for the murder of EMI signals