Noisy guitar - any ideas to fix it?

allen

Hi there,

I’ve got a tom Anderson drop top with 3 x p90s and it’s really noisy. I’ve got a few other single coil guitars and the noise doesn’t bother me (they’re a lot quieter), but this one is constantly buzzing when plugged in. 

They’re supposed to be Anderson’s noiseless p90 (PQ1). Ironic. 

Even when selecting the in between pickup position it keeps buzzing. 

I emailed Tom Anderson but he wasn’t much help. He suggested maybe shielding the pickup cavities.

If I touch the strings or metal parts the buzz reduces but doesn’t disappear entirely.

I opened up the back and found what looks like a total horllicks of a wiring job. https://imgur.com/gallery/xFe3Hs7

Could this be solved by rewiring more tidily, twisting the wires, copper foil on the back cover, etc. 

Please don’t say that it’s all part of the p90 experience. 

I think I’m probably headed towards a set of kinmans. 

 

ICBM

P90s *are* noisier than most other single-coils - Jazzmaster pickups aside - but if they're supposed to be noiseless it does sound like there's something wrong.

Rewiring it neatly and fully shielding the control cavity with copper tape is where I would start, since it does sound like a shielding issue.

sweepy

Silly question but who knows, have you tried a different lead and have you tried turning off anything that sits on the same socket or ring as your amp ?

Funkfingers

allen said:

Anderson’s noiseless p90 (PQ1). 

Unless Anderson has created something worthy of patenting but told nobody about it, there are two ways to cancel hum from a P90-sized pickup.

1. Dual coils 
2. a hidden dummy coil, acting in opposition to all three visible pickups.

allen said:

I opened up the back and found what looks like a total Horlicks of a wiring job. ... Could this be solved by rewiring more tidily?

Probably not.

A few more photographs from other angles might help with remote diagnosis. In the mean time, how many conductor wires emerge from the outer insulation on the cables from each pickup?

The four pole Superswitch only makes sense if there is some coil splitting going on in some of the pickup permutations.

Rocker

Send an email explaining the problem to Anderson, there might be a simple fix [wire borken or similar]

Collings

The Tom Anderson PQ pickups are indeed dual coil pickups and the output leads have 4 wires so I would check that they have been wired correctly using both coils wired for humbucking rather than just a single coil.

Jimbro66

Collings said:

The Tom Anderson PQ pickups are indeed dual coil pickups and the output leads have 4 wires so I would check that they have been wired correctly using both coils wired for humbucking rather than just a single coil.

It’s hard to believe that the wiring job shown in that photo was done at Tom Anderson’s workshop. The soldering on the volume pot casing looks amateur. Did you buy the guitar new @allen or had a previous owner messed with it? If the latter @Collings could well be on the right track regarding incorrect wiring. In any event it would pay to screen the control cavity, including the back of the cover, and check the grounding of the pickup cable shielding as others have advised.

ICBM

Funkfingers said:

The four pole Superswitch only makes sense if there is some coil splitting going on in some of the pickup permutations.

I can’t quite see clearly enough in the pic, but it would also be necessary if the middle switch position is neck+bridge, which can’t be achieved with a standard 5-way. Only three of the rotors are in use so that’s a possibility.

The pickups appear to be wired as series humbuckers with no splits - green and white wires connected and insulated - although only one is totally visible.

allen

Thanks everyone for the constructive and helpful comments.

They are 4 wire pickups and from my original examination they are wired using all 4 wires.

I think the superswitch might be used as there is a push pull on the tone pot to engage the bridge pickup (i.e. to allow neck and bridge pickup to be used together)

I agree with @Jimbro66  - the soldering looks really amateurish to me. The solder on the back of the pot is burnt. I bought the guitar second hand so it's very possible that someone messed with it. In fact the previous owner had completely messed up the trem setup too.

Control cavity appears to have black conductive paint in there, but the control cavity cover is not shielded.

I must admit I don't fancy the whole project of taking pickups out, shielding everything and then rewiring everything, but I think it's my best chance. And it's a fantastic guitar to play in every other way.

I wish that there was a way of switching the pickups between series and parallel, but I've investigated previously and it's not possible with 2 push/pulls as far as I know.

Allen