SWR Redhead Humm


2016-02-05 11:16 pm
Working on an SWR Redhead Bass amp (240W), MFG in 1997. The amp is producing a hum. Signal goes through pre-amp and power amp, sounds good except for the hum. The hum is present with no input and master volume and gain low. Replaced some caps that had some visible bulging on the power supply (4700uf, 63v), no change. Any suggestions on where to look?