[darkbluemurder]

- Custom shop guitar with JB: squeals like crazy but if I press the pickup against the body it improves considerably.

Same category as loose wiring. A loosely mounted pickup can cause this phenomenon. Either put a piece of foam under the pickup to keep it tightly mounted or replace the springs with rubber tubes. If you use rubber tubes, be careful to not make them too long to keep the pressure manageable. There is some trial and error in this process so don't give up.

Good luck,
Stephan

[Guitar74]

I would look at pickups and how loose or tight they are. I just tried an experiment with my Big Apple Strat as the Pg+ likes to squeal. Pickguard mounted pickup. I have a kamikaze with a direct mounted pickup. No squeal. placed padding in the cavity behind the pickup on the Big Apple. Conclusion? Squeal gone!

I know I didn't originate this thread, but it helped me out quite a bit. Now on to my Jackson Dinky!

[BluesJam]

+1.    Years ago my Keeley modded TS9 was to blame for my annoying squealing and high pitched feedback.  Sometimes the culprit comes from an unexpected source.  Additional troubleshooting of your rig may be in order.