Conrad-Johnson Amplifier Repairs

Conrad-Johnson MV55 Stereo Amplifier

When one of the bias adjustments was being made, noise was heard from the speaker, which clearly wasn’t right. I cleaned the dust from the top of the PCB and noticed several areas where the solder joints were in poor condition.

Overall, the PCB was in surprisingly good condition considering the amount of heat generated by the valves. However, the heater diodes for the smaller valves, along with the diodes in the voltage regulator supplying the output amplifiers, appeared to have been working particularly hard and showed signs of heat stress.