Tommy's Non-Reverse Firebird/Jazzmaster/??? hybrid dream guitar build

[Simon Barden]

Well done on sorting the sound out. It really is worth messing about with the pickups. I don't do it enough.

[tommycarlos]

Here's a question.

I got copper shielding tape to try and keep this guitar a bit quieter.

However... usually, I see shielding tape on pickguards that have actual pots or other controls on them, but this guitar is a bit different. The pickguard is not connected to any of the actual electronics, only the body.

If I wanted to shield this guitar, would I still shield the pickup cavities and the back of the pickguard, as well as the control cavity and the back of its cover? Then connect a ground wire between the two shields as well as one from the shields to the volume pot or whatever to ground it all?

Instead of soldering said ground to the volume pot, could I connect it to the bridge/tremolo like the other ground wire?

[tommycarlos]

While I am asking questions... is there any possibility that the covers on the p90's being fairly loose cause any microphonics, or is that just vibrations with metal covers?

[Fretworn]

I think gold foils have a tendency to be microphonic, and P90s aren't renowned for being quiet either.

[tommycarlos]

Yeah, but GFS claim to have wax potted these... i think it’s a frequency thing.

I did an A/B test and my Jag is almost the same (they sound very similar). I think I had just gotten used to the P90s in the JZ-1 and My Jazzmaster.

:/

I do like how it sounds.

I am recording weekend after next (first recording with this band/rig)... that’s why I am concerned about noise and feedback, etc. I have a lot of guitars though, so one of them is bound to sound good in the studio.

[Simon Barden]

What you do is foil shield the underside of the pickguard and the pickup cavities, but go over the edge of the pickup routs so you have some foil on the top of the guitar, but hidden by the pickguard. Run foil over the top between the two cavities and out to around the two rear pickguard screw holes so that when you screw the pickguard down, the two foil surfaces are touching under pressure and so provide a ground path.

Check the foil with a multimeter for conductivity/low resistance at all points. I find that overlapping sideways strips need to have a couple of strips running perpendicular across them to join them all together for guaranteed contact.

Now you just need to run one ground wire from the bridge cavity to the back of a pot (you've joined the two cavities together with the tape over the top so you only need one connection). You can solder the wire to the foil, or you can use a small screw and washer, with the bare end of a ground wire wrapped around it, and screw that into the side of the cavity. Avoid screwing into the bottom (as it makes sitting down painful ). It's not worth risking a screw poking out through the back of the guitar.

Metal pickup covers need to be waxed on to the pickup to stop the vibrations of the metal causing extra microphonic noise. The metal vibrating induces a current just like a string does, but being nearer the magnet and in a stronger magnetic field, it doesn't need to vibrate as much to produce an audible signal. Metal covers are obviously stiffer than a string so don't vibrate that much at all, but can induce squealing at high volumes if not damped by connection to the pickup via wax. Plastic covers won't won't do that.

What you can get with pickups surrounded by a pickguard is a 'static' noise as you rub your hand over the guard. This does depend on the pickguard material and this may not happen at all, but I did encounter it the other day on a friend's Squier Tele. Foil shielding the back of the pickguard ensures that any static charge generated on it is taken straight down to ground, so you don't get any occasional crackling noises.

[Simon Barden]

Wax potting can take two general forms - light and heavy. Light is a wax immersion for a shorter period so that the wax doesn't penetrate all the winding gaps, allowing some movement but allowing a higher volume level before microphonics become noticeable. Heavy lets the pickups soak for much longer, so the coils are all held firmly in wax, for much higher volume and gain levels.

The best sounding pickups are often microphonic or only lightly wax dipped. PAFs weren't potted at all, and there is generally more top end and 'clarity' to an unpotted pickup compared to a potted one. But there are issues with volume and gain as a result. There are also degrees of microphonics. I've had some Tele pickups go very microphonic so that you couldn't turn a clean amp up to a reasonable level before it started squealing like mad.

[tommycarlos]

Awesome explanations as always Simon. Thanks!

[tommycarlos]

Just wanna say that this guitar was amazing in the studio over the weekend.



Huge thanks to Rosser Guitars and anyone that helped out with advice, etc.

[FrankenWashie]

That is a sick shot and an awesome looking axe man. Great job!