OK, today I had some spare time on my hands and decided to tidy up a mod I did to my ProCo Dirty Rat a while back.

The idea behind it was to install a power switch so that I dont need to unplud the thing after every use, I can just hit the switch and save on batteries. Originally, this was just a switch on the wire running from the battery to the pcb, and that worked fine.

I wanted to tidy it up and remove the connector for the adaptor and also cut down on the excess wires inside to make room for further mods over the christmas period.

This went OK, I managed to locate the points where the power goes into the pcb, and hook up the battery to these point, going via a switch to cut the power.

But now, it seems to to have started oscillating. It changes pitch and volume with the adjustment of the controls, and is still present no matter what is connected (different guitars, mp3 player, etc) and the battery is brand new and is only been lightly used.

Anyone got any ideas on what I've done, and how to fix it?
Quote by Dave_Mc
how do those marshall handles compare tonewise to, say, mesa handles?

Owns a Blackheart Little Giant...