This is my first post on this forum so please be gentle 
I was given a Crate B80XL bass amp (80W/1-15 combo). It works quite well but it hums whether my passive Peavey Grind NTB-5 is plugged in or not. The guy that gave it to me said it 'always' hummed.
I haven't gone beyond preliminary troubleshooting but so far (I think) I have determined the hum is coming from the power amp section as the hum doesn't get louder or softer or change character when I move any one of the controls. I hope I am correct in my presumption(s) so far. Does anyone here know where I can get a schematic for this amp? Or does anybody have any experience with this amp (or its relatives) in curing the hum problem?
Otherwise, when I finally get to open it up (not soon - my work area is being painted), I will:
1) Clean every control, switch, jack, etc. I can access.
2) Check all of the grounds to make sure there are no cold solder joints
3) Test all of the power supply caps, diodes, etc....
Any other thoughts would be helpful!
AAC
I was given a Crate B80XL bass amp (80W/1-15 combo). It works quite well but it hums whether my passive Peavey Grind NTB-5 is plugged in or not. The guy that gave it to me said it 'always' hummed.
I haven't gone beyond preliminary troubleshooting but so far (I think) I have determined the hum is coming from the power amp section as the hum doesn't get louder or softer or change character when I move any one of the controls. I hope I am correct in my presumption(s) so far. Does anyone here know where I can get a schematic for this amp? Or does anybody have any experience with this amp (or its relatives) in curing the hum problem?
Otherwise, when I finally get to open it up (not soon - my work area is being painted), I will:
1) Clean every control, switch, jack, etc. I can access.
2) Check all of the grounds to make sure there are no cold solder joints
3) Test all of the power supply caps, diodes, etc....
Any other thoughts would be helpful!
AAC