Concert Bass amp - hum/buzz

[mckinnon audio]

   Hi there,the fact that the hum decreases considerably when you turn 90 deg. really points to single coil pickup hum.Check all the ground connections in the bass and clean up the 1/4" jack the same way you did to the ones in the amp.Make sure the pickup leads are twisted all the way to the controls.Sounds like it's becoming a bit of a "search and destroy" mission,but eventually you'll find it.On the plus side,you're going over your gear with a fine toothed comb,so everything will be working well when "it's" over.Good luck,Mel.

[brianl-cdn]

Mel, as you suggested, I twisted the Jazz bass' pickup wires, and reseated the jack on the plate. Everything is clean and solid, but the hum is still there. I've found some cancellation by tweaking the pickup volume balance, and the other bass still hums less (now the AC plug is fixed), so I guess it's "normal" single-coil hum. Like you said, it's good to have gone through everything and know it's working, pots and connections are clean, etc.

Since the amp has a bit of hum that doesn't increase with volume, it could probably benefit from new caps, but since it's only mild, I'm hesitant to mess with it (or spend money on it), before selling it.