Guitar mod idea; does this work?

[Gtr_tech]

That's a poor way to wire things up. You are relying on a mechanical connection to establish ground. If the connection becomes lose or oxidized, there goes your ground.

All the backs of the pots should be wired together. You do not need a single ground point. This is a based on the myth that you can have a ground loop in a guitar, which you can't, because it only has a single ground at the output jack. The fact that his noise didn't go away shows this.

Ground wires do not lead to ground. Ground wires ARE ground.

No.....I said gnd *everything* but the tone pots to a single point....the back of the vol pot. Gnd will be fine, and only the tone pots will gnd thru the foil. If there's tooth washers used, the foil gnd won't work so well 'cause those washers will tear up the foil. In that case I'd trim the foil around where the nut/washer contact the pickguard and use a solid 20awg gnd wire across all 3 pots. Then you still have the single gnd at the vol pot. Star grounding *does* make a difference, but it sure won't fix a noisy p-up due to improper wiring.

[jakeac5253]

It sounds like the humbucker has it's two coils out of phase (in phase actually). You have it wired up correctly though, but just to see, swap the green and red wires and see if it doesn't get quiet and sounds fuller.

Also make sure the base plate has continuity to ground via the bar wire.

How is your volume pot wired? I don't see a connection to the center lug.

Thanks for the suggestion David.

I have now included the tone pots in the star ground and now everything is grounded to the back of the volume pot. Continuity checks out and the volume pot shows continuity to all points of interest i.e. the jack, the other components, the ground plate screwed into the body wood, and the bridge itself. There is nothing connected to the middle lug of the volume jack in the above picture because I hadn't wired the pickguard to the guitar yet, just wired the pickguard. The jack tip is now wired to the middle lug of the volume pot.

Since my last post I have also bridged the switch commons and moved the tone circuit connections to the associated pickup contacts on the other side of the switch rather than have everything connected to the same contact point.

The cycling noise has been diagnosed as electrical interference and is only present when I am sitting in front of my computer. I thought that pickguard shielding was supposed to stop this though?

I tried switching the black and white wires (it was just an easier swap) and the pickup got even thinner and spankier sounding, so I swapped them back. I think most of the problem is the fact that this pickguard has the bridge pickup mounting hole placed 1/8" closer to the bridge than my previous one, so it sounds thin by comparison to me.

[Gtr_tech]

Thats EMI from the monitor. There's no way to avoid it.....the guitar's p-ups will be sensitive to it and no amount of shielding will change that. Since its magnetic in nature, your pickups love to...well....pick it up. There are countless things that emit EMI that is strong enough to be sensed by guitar p-ups. Cordless (or corded for that matter) drills, remote controls, cell phones, anything with a motor in it or coils of wire passing large-ish currents.

[jakeac5253]

Thats EMI from the monitor. There's no way to avoid it.....the guitar's p-ups will be sensitive to it and no amount of shielding will change that. Since its magnetic in nature, your pickups love to...well....pick it up. There are countless things that emit EMI that is strong enough to be sensed by guitar p-ups. Cordless (or corded for that matter) drills, remote controls, cell phones, anything with a motor in it or coils of wire passing large-ish currents.

Oh, I see, so it's magnetic. Well... you CAN fix the problem by shielding a pickup cover... but then it wouldn't be too effective as a pickup at that point

[Gtr_tech]

Oh, I see, so it's magnetic. Well... you CAN fix the problem by shielding a pickup cover... but then it wouldn't be too effective as a pickup at that point

Only if you encased the p-up in mu metal. Regular PAF style humbuckers are almost fully shielded and are still subject to EMI just like any other p-up.

Just in case you're interested, here's the part of you monitor that likes to talk to your guitar p-ups:
http://www.jestineyong.com/wp-conten.../yoke-coil.jpg

The part with the orange-ish wire coiled around it. Thats called the "yoke" and makes up an electromagnet that "steers" the electron beams to where they need to be....making the picture fill the front of the tube.

If you held a guitar in front of an old arcade game that uses a "vector" monitor, you'd get *real* interesting sounding EMI thru your amp. A vector monitor doesn't operate like a std tv type monitor. Instead of scanning continuously in lines and drawing a pix, it draws lines directly point to point. So the yoke coils are driven by what are essentially audio power amps and only draws when instructed to by the game's hardware. I have a Tempest in my collection of "golden age" arcade games and if you take the back cover off and operate the game, you can hear the yoke coils vibrate slightly....."singing" to you while the monitor draws the game images on the tube. Its pretty trippy sounding.....I can imagine what it would sound like thru an amp....gotta do that sometime just because.....

[jakeac5253]

Only if you encased the p-up in mu metal. Regular PAF style humbuckers are almost fully shielded and are still subject to EMI just like any other p-up.

Just in case you're interested, here's the part of you monitor that likes to talk to your guitar p-ups:
http://www.jestineyong.com/wp-conten.../yoke-coil.jpg

The part with the orange-ish wire coiled around it. Thats called the "yoke" and makes up an electromagnet that "steers" the electron beams to where they need to be....making the picture fill the front of the tube.

If you held a guitar in front of an old arcade game that uses a "vector" monitor, you'd get *real* interesting sounding EMI thru your amp. A vector monitor doesn't operate like a std tv type monitor. Instead of scanning continuously in lines and drawing a pix, it draws lines directly point to point. So the yoke coils are driven by what are essentially audio power amps and only draws when instructed to by the game's hardware. I have a Tempest in my collection of "golden age" arcade games and if you take the back cover off and operate the game, you can hear the yoke coils vibrate slightly....."singing" to you while the monitor draws the game images on the tube. Its pretty trippy sounding.....I can imagine what it would sound like thru an amp....gotta do that sometime just because.....

Hey cool, thanks for the pic. Do they have those in LCD monitors? That's what I have, iMac to be exact. If you ever get a recording of the whirring sound from the arcade game let me know, I'm curious to see if I'll recognize it or not.

[Gtr_tech]

LCD monitors don't use a tube, so there is no yoke. EMI noise from those would likely be from the inverters used to create the HV for the flourescent backlighting.

Unless you've had your head in the back of a Tempest game in a quiet room I doubt you ever heard anything like it. Its quite unique.....I think it sounds like a long zipper that starts and stops while changing frequency.

YouTube - Atari Tempest Restoration on bench working !!

Toward the end of that video, if you turn your sound up quite loud you can hear the yoke chatter when he films the back of the monitor. Its kinda hard to hear due to the ambient noise in the room masking it.

Here's a cool way of exploiting the problem:
YouTube - Tempest - Make your monitor play Beethoven!

Skip ahead to around the 40 sec mark. That shows a guy with a program designed to run the monitor at specific frequencies. When the EMI is picked up by a cheap little radio, its kind of a cool effect. Dunno why its called "tempest"....cool coincidence tho.

[David Schwab]

I use my CRT monitor to test the shielding in my bass pickups! It's very hard to eliminate EMI noise. Light dimmers are another source.

I was playing in a band for a while and we rehearsed in the drummers basement. We had this constant whining noise coming through the amps, even though we had humbuckers. It turns out the guy had one of those invisible fences for his dogs. When he turned it off the noise went away.