WRH / TB Pickup Project: Magnestism and Grounding Questions

[David Schwab]

This:

will of cause shange everything when it comes to grounding, ground loops, the need to ground the braid of coax cables etc.

There's no ground loops in guitars. There's only one ground.

The aluminum body will just become one big ground plane. Just like having the cavity lined with foil.

Everything else should be wired as normal.

[Mike Sulzer]

An aluminum body is the world's best electrostatic shield. You do not need to use shielded cable. Using shielded cable but not grounding the shields will not cause a problem in this case, except maybe confusion.

If the jack is grounded through the body*, then if you have it wired backwards, you should get nothing. (Your "hot" or signal lead would be directly connected to ground.)

So that is probably not your problem. (And it does not look like it is backwards.)

I do not see the wires from the pickups in these photos. Is it possible they got connected to the incorrect terminals on the vol. pots?

*Is there an insulating layer or finish? If not, then you have each pot and the jack connected to the body (grounded) when it is screwed in place (unless you have intentionally isolated them with insulating washers).

[Man@Large]

Thanks for all of the suggestions and feedback, guys.

You know how a problem like this is often something pretty simple? Well, I tried every damn thing. I went from the pickup straight into the output jack; nothing. I removed the jack from the body and did the same thing; nothing. So, running thin on options, I plugged my Tele into the same amp (Traynor YBA-1A, fresh from the tech) and got the same weak, ground-problem sound.

When I plugged into another amp I got the full output of both pickups. They sound fantastic, but I still think I have some sort of grounding problem.

The volume pots are finally bleeding into the tone pots, but the volume pots themselves still seem to only let the sound pass straight through to the switch. The output comes on strong between 0-1, and it sounds like I have a little bit of control up to about 3, but then they're wide open.

So now what is the answer?

I haven't isolated the pots yet. I considered it; bought a bunch of fiber washers, felt washers, etc. I didn't think about it until it was too late, but the ground wires on the backs of the pots, and the ones going to the switch and jack are a little bit redundant. EVERYTHING on this guitar is grounded.

Would isolating any of these components get better results. Again, I considered isolating them but my logic suggests that this wouldn't actually change anything.

And the less relevant question: WTF is wrong with my amp?

[Man@Large]

I do not see the wires from the pickups in these photos. Is it possible they got connected to the incorrect terminals on the vol. pots?

Fuck....so possible, in fact, that it is exactly what happened.

That's what happens when you are in a hurry. Now I'm embarrassed.

[Mike Sulzer]

It happens.

No need to isolate the pots and jack from the "chassis" in an aluminum guitar. You have the best shield against electric fields from dc to damn near X-rays.

[David Schwab]

An aluminum body is the world's best electrostatic shield. You do not need to use shielded cable. Using shielded cable but not grounding the shields will not cause a problem in this case, except maybe confusion.

I didn't realize it was an aluminum guitar when I posted that! He also probably doesn't need the ground wire linking all the pots together.

I do not see the wires from the pickups in these photos. Is it possible they got connected to the incorrect terminals on the vol. pots?

I was wondering the same thing. I didn't see any pickup wires. He said the tone pots didn't work, but they look fine in the photo, so it had to be an issue with the pickup wires.

[RedHouse]

Fuck....so possible, in fact, that it is exactly what happened.

That's what happens when you are in a hurry. Now I'm embarrassed.

Don't worry 'bou'dit, I really like your nice neet wiring, keep up the good work!

[Man@Large]

Hey, guys. Thanks for all of the help and information so far. My original "problem" was a simple, embarrassing oversight; now I'm moving on to fine-tuning the tone of these pickups.

I've had quite a bit of time to play them, used several different amplifiers, etc. I'm very happy, especially for my first build. But my bottom line is that I would like to get the single-coil to exhibit a little bit more clarity in the lower mid-range.

An acquaintance with considerable talent and experience recorded some samples with my guitar. He showed me that the single-coil (neck position) was a bit "thick" in the 250-300 gHz range. We shaped it a touch with some software; I have to consider the resulting change an improvement.

I'd like some advice about how to get this change without making considerable modifications to the main construction features of the pickups. Basically, shouldn't I be able to get there with pots and caps of different values?

Current Setup for the single-coil (neck):

500k Volume w/ .001 bleed cap
250k Tone w/ .015 cap

Thanks!

[Mike Sulzer]

I do not think so. Changing the resistance across the pickup affects the frequency response most near the resonant peak, that is, maybe 2.5 to 5 KHz in most pickups. There is no need to try a different pot to see what the effect is because you have a tone control. Since the tone cap is essentially a short circuit at frequencies near the resonance, turning the tone control down from ten is just changing the resistance across the pickup. As the tone control gets closer to zero, the cap starts to matter.

This also implies that changing the value of the cap will have essentially no effect on the tone when the control is on ten, or mostly turned up. That is, the cap value mostly affect that bassy sound you get with the control nearly on zero. This is what I measure and hear. There are guys who disagree, but let them make their case.

Hey, guys. Thanks for all of the help and information so far. My original "problem" was a simple, embarrassing oversight; now I'm moving on to fine-tuning the tone of these pickups.

I've had quite a bit of time to play them, used several different amplifiers, etc. I'm very happy, especially for my first build. But my bottom line is that I would like to get the single-coil to exhibit a little bit more clarity in the lower mid-range.

An acquaintance with considerable talent and experience recorded some samples with my guitar. He showed me that the single-coil (neck position) was a bit "thick" in the 250-300 gHz range. We shaped it a touch with some software; I have to consider the resulting change an improvement.

I'd like some advice about how to get this change without making considerable modifications to the main construction features of the pickups. Basically, shouldn't I be able to get there with pots and caps of different values?

Current Setup for the single-coil (neck):

500k Volume w/ .001 bleed cap
250k Tone w/ .015 cap

Thanks!

[Man@Large]

I do not think so. Changing the resistance across the pickup affects the frequency response most near the resonant peak, that is, maybe 2.5 to 5 KHz in most pickups. There is no need to try a different pot to see what the effect is because you have a tone control. Since the tone cap is essentially a short circuit at frequencies near the resonance, turning the tone control down from ten is just changing the resistance across the pickup. As the tone control gets closer to zero, the cap starts to matter.

This also implies that changing the value of the cap will have essentially no effect on the tone when the control is on ten, or mostly turned up. That is, the cap value mostly affect that bassy sound you get with the control nearly on zero. This is what I measure and hear. There are guys who disagree, but let them make their case.

Okay, I think I understand. And that's pretty relevant to what I was discussing with the person that was helping me with this R&D. He said that he usually hits 10 all the way around on his guitars, and then really uses the amp to dial in the tone. His main point was that it's an easier way to keep your tone consistent in a live performance situation.

Even though that's not what I do when I play (because you're forsaking a lot of tones), it makes sense, and I imagine that lots of guitarists do this.

The pickup in questions sounds perfect with the volume at about 8; gains a lot of presence. But when I go up to 10 there is a notable increase in the muddiness, much more than what I am used to. The bridge humbucker has the same volume pot but has a more consistent tone across the volume curve. Does that sound like something that can be fixed?

Thanks again.

[Man@Large]

How much smarter do I need to be to make sure that my posts go at the end of the thread?

[Billy Bones]

That wiring is an inspiration!

Billy Bones