express bright switch squeal

[Randy Magee]

Is there a secret to the placement of the capacitors on the bright switch to eliminate a squeal that is induced. I hadn't really worried about it as I use a Strat with single coil pickups and the amp is plenty bright already, but I thought I might try to clean it up for future use. The amp is stable dimed, but even when turned down a bit, if I flip the bright switch either way, I get some squeal. I used the standard layout stacking them against one another with some silicone between them...

[selloutrr]

some brands/types of silicone are mildly conductive.

As well as some brands of capacitors coatings are not as shielded as you would think they are.

[fishy]

There are two recognized ways to wire this I know of and you might find it uselful to read the following thread. It is a a subtle difference but it all adds up.

https://tubeamparchive.com/viewtopic.ph ... ht+antenna

[M Fowler]

I wire mine the colossal way.

[Randy Magee]

Mark, I may have to try your method after I get a new switch... I already have the caps hooked to the outside lug on the volume pot, but something is causing some signal intrusion, hence the squeal...

[M Fowler]

Yeah I have had that same problem on my Express Combo apparently the wring was causing the problem. I switched to using this method of brite switch on all my amps. Keep the leeds short as possible.

DPDT mini toggle switch 3 position on-off-on.

Mark

[Randy Magee]

Well I just used the same bright switch and separated the capacitors away from one another and the squeal went away. Evidently my problem was the capacitor's proximity to one another... learn something every day, huh?

[M Fowler]

Yeah its crazy how lead dress can make or break your day

Mark