Hi all. I recently had to change the POTS in my Musical Fidelity A5 integrated as the old one only rotated a 1/4 turn. The new POTS is an exact latter day version of the original POTS. At listening distance, there is a noticeable hum from the speakers since the POTS was replaced. The hum doesn’t increase/decrease with volume.
The transformer also used to hum a little but only noticeable at very close distance. The transformer noise is now audible from listening distance. I have changed power cords, speaker cables, disconnected the only source, and the buzz persists. Nothing else in the environment has changed or further afield in the house.
Has anyone any suggestions before I buy ferrite beads for the power cables?
It sounds like a ground loop, but odd it showed up only after a component was replaced.
Have you tried a cheater plug which lifts the ground to the unit?
Have you tried unplugging everything from the integrated leaving only the power and the speakers connected and checked if the hum remains? If it goes away you have a classic ground loop.
I seem to have found the problem. The tech didnt mount the POTS to the PCB properly and also left a lump of electrical tape on the PCB under the POT. Buzz barely audible now but will still bring back.