P90 Feeding Back

Crazed_Fandango

The bridge P90 on my guitar (Ancoats) squeals horribly under high(ish) gain; the neck P90 is fine.

Are there any obvious things I can do to stop this with my limited skills, or am I looking at a replacement pickup.

Funkfingers

What mounting type is the offending pickup? Soapbar, dogear or -330/Casino?

Crazed_Fandango

Soapbar. Mounted onto 2 bits of foam.

Funkfingers

Possibility #1
Insufficient foam packing beneath the pickup. It ought to push the pickup firmly against the heads of the height adjustment screws.

Possibility #2
The pickup coil was not wax potted properly.

Possibility #3
A previous owner custom ordered the offending pickup with little or no wax.

Possibility #4
A previous owner changed the bridge position pickup for an inferior replacement.

Crazed_Fandango

I'm the 1st owner of the guitar and the pickups made and wound by Ancoats, so hopefully Possibility #1 is where I need to go, or it'll be a pickup swap (unless I can get it wax potted).

Thanks for the help @Funkfingers. 

Dave_Mc

How long have you had it? If it's still under warranty he should fix it for you. But definitely do what @Funkfingers suggested with the foam there, he's spot-on there (as usual!) with his suggestions- it may not be a problem with the pickup (and P90s can be noisy anyway).

Are the screws holding the pickup tightly to the body? That might be another source of microphonics if the pickup can vibrate.

Crazed_Fandango

I've had it a year and no doubt he would fix it, but shipping cost and hassle puts me off.  This isn't P90 noise, this is very loud feedback.

No, I can push the pickup down as the foam is quite loose.  I've tightened the screws as much as possible, but there's still 3-4mm movement.  I guess I could try some small wood blocks under the foam.

Funkfingers

More (or firmer) foam padding, methinks.

Readjust the pickup to its previous height setting.

If the guitar still howls, squeals, whistles or runs into feedback whenever the strings are not palm muted, it probably wants another dip in potting wax. 

Talk to Ancoats Guitars. Explain the problem. You might get away with just posting the pickup.

Dave_Mc

Good point about the shipping- you can't rule out something going catastrophically wrong when it's in the hands of a courier! 

As @Funkfingers says, try some better foam etc. first. With a bit of luck that might fix it. If not, and assuming you can solder, it definitely makes more sense, as he says, to just send the pickup, both from a cost and from the "something going catastrophically wrong" point I made above...

OilCityPickups

Another possibility is poorly gripped magnets ... the screws holding the bobbin to the baseplate also clamp in the magnets, if they are a little loose and can vibrate ... hey presto squeal