The filter caps are the capacitors that make up the part of the circuit that filters the power supply on an amp. If you take the amp to an amp tech, replacing caps is a relatively easy (and usually inexpensive) job. It's a very common thing for older amps to need caps replaced because many of the caps used back in the day are electrolytic and actually dry out over time.
I don't know where you are located, but someone on here probably knows a reputable amp tech in your area if you want to let us know.
― martin m. (mushrush), Tuesday, 21 February 2006 23:32 (nineteen years ago)