I'd try to isolate the problem by connecting components in reverse. Ie start with just the speakers connected to the amp with everthing else disconnected. If no hum then add one item at a time. Ie a pre-amp to amp cable, then the other one then the pre-amp, and continue until you get the hum.
May also need to use ac cheater adapters on each component.
Tranformer hum is usually a 60 cycle vibration. If it were the source, the amp will vibrate and the speaker woofer should be quiet.
Other sources of noise can be anything with a motor, flourescent lights, electronic dimmers, items with high/low switches and computers. Try temporarily disconnecting suspect items to see if hum disappears.
Hope this helps. Hum problems can be aggrevating.
May also need to use ac cheater adapters on each component.
Tranformer hum is usually a 60 cycle vibration. If it were the source, the amp will vibrate and the speaker woofer should be quiet.
Other sources of noise can be anything with a motor, flourescent lights, electronic dimmers, items with high/low switches and computers. Try temporarily disconnecting suspect items to see if hum disappears.
Hope this helps. Hum problems can be aggrevating.