Bogner Alchemist squeal!

[Theroc165]

having a strange problem when I engage the effects that are on board my bogner alchemist. when I engage them it sounds like some weird delay phase swelling and feedback squeal. it only happens after the amp has been on for a minute or so and it slowly builds until its crazy loud. ive tried replacing the preamp tube that is the effects tube V4. nothing has worked any ideas guys would be welcomed

 

[sahlomonic]

It could be a bad capacitor somewhere. I've experienced that with 2 of my amps over the past few years. I do know that the Alchemist has a lot of connections that are PCB terminal blocks instead of soldering straight to the board. Maybe a connection got loose, and you'd just have to plug it back in. Spraying the board and connections with De-Oxit contact cleaner might also help.

 

[Theroc165]

Thanks, any ideas where I might start to look its has several boards in it?