My SC 500 just randomly decreases in volume by like ½ while I’m playing and won’t increase again. I usually turn the gain way up to compensate then it’ll eventually get loud again. What’s going on with it? I use passive basses with different cables. Any suggestions?
If the amp has an Effects Loop try linking the Send and Return with a signal cable. Sometimes the contacts in the switches attached to these jack get corroded and cause all sorts of troubles.
Also that 500 had a series parallel toggle to their effects loop by pulling one of the balance knobs... Try manipulating those also