Got a hum

[scheek]

I just replaced both pots and output jack on a Musicmaster bass, a single PU. The pickguard does not have grd foil.

I purchased the pots and output jack prewired. I feel they are right. There are no switches.

I have a grd coming from bridge that is grd to pot.
I have a grd from PU to pot
I have red wire from PU to lead wire on vol pot.

However, I have a hum. I have not put strings on. Guitar cord is good. Other guitars do not hum with amp.

I disconnected PU and it still hums. I can tell that the vol and tone are working. Vol off cuts hum.

Any clues?

 

[JimmyM]

Ground wire to the bridge hooked up?

 

[scheek]

Yes. It is. However, I did alligator clip to bridge and to one side of output plug and it stopped. I hooked it to the hot side thought. Go figure. Does that make sense.

 

[scheek]

Will not having strings on make it hum?

 

[JimmyM]

Yes, I have had hum problems on basses with no strings that went away once strung. Not sure why, though.

 

[bassmanbiff]

because the grounded strings acted as further shielding.

 

[scheek]

Trouble shot and found that my single pickup was bad. Temporary, I hooked up a strat 6 pole single pole and it worked. Still got a hum WITH strings. Stops when I put my hands on strings. Too, I have a tremendous amount of treble. The pots are wired for a P_bass which is wrong. I should have wired for a MUsicmaster bass. This is my fault though. the harness which I got off ebay (a good one) was pre-wired for P-Bass. I'm thinking I may have to undo the soldering an re-wire. I need a good schematic thought.

I'm not sure if the 6 pole has any affect on the treble. Whatcha think.