Hello, I recently acquired an old mid 70's Univox Stage 400 (90 watt, 2x10) amp. I have cleaned it up and replaced both speakers, but there is a lingering low end issue that I cannot diagnose. Even with the settings all at "Noon" (Cilpping and Reverb set to zero), the low end of the amp is really farty, flabby and distorted. Even with the Bass set to 1 or 2 on the dial, it still distorts. I have cleaned all of the pots and dusted and instected the circuit board. I am less familiar with solid state amps than I am with solid state amps. What could the culprit be? Could a filter cap replacement help resolve the situation? Any advice would be appreciated.