Double Bass Piezo pickup hum

[prsussmann]

I get a low cycle hum when plugging my double bass Fishman pickup directly into my amp. Hum goes away when instrument cable end is grounded by touch. Is this what a pre-amp like an Hpftech would solve?

 

[DoubleMIDI]

No.
Try a different cable. I guess you have a bad shield connection. Maybe there are only a few strands left making the electrical connection from cable to plug on either end. It also might be a bad shield connection on the pickup side, broken pickup cable, loose connection inside the adjuster or (most probably) a bad shield connection from RCA plug to 1/4"-adapter.

 

[prsussmann]

No.
Try a different cable. I guess you have a bad shield connection. Maybe there are only a few strands left making the electrical connection from cable to plug on either end. It also might be a bad shield connection on the pickup side, broken pickup cable, loose connection inside the adjuster or (most probably) a bad shield connection from RCA plug to 1/4"-adapter.

Thx for the info - must be a bad shield connection or compromised cable in the pickup. Time for some soldering I guess...

 

[BobKay]

Using Deoxit spray cleaner in all the jacks fixed an identical problem for me. I went through cable switching, etc. turned out to be dirty connections.

 

[Les Fret]

I have the same problem with my Barcus Berry Outsider pickup on my sitar. When I touch something the hum goes away. I solve this by attaching a small iron wire going from my jack cable plug to a string of the sitar. That is sort of a McGyver solution. But not the best solution. It has nothing to do with the instrument jack cable. I would really like to know how to solve this and why this happens..

 

[Les Fret]

No one any solution for this annoying ground hum? I guess many pickups have that hum.

 

[drurb]

Ground loops can be a pain (if that's what it is)! I assume that your solution keeps things quiet even when you're not touching a string. What device is the pickup plugged into? What device comes after that, if any? How are those devices grounded?

 

[MR PC]

If you have a good active direct box, like the Countryman, and an amp with XLR input..flip the ground on the direct box. This has worked for me in diminishing the hum. On my Underwood equipped EUB with a metal tailpiece, I added a ground strip 'tween the tailpiece and the output jack. Still have the hum sometimes, and don't always use an amp with XLR input. PITA, seems that's just the way it goes with piezo pu's under pressure.

 

[Les Fret]

Ground loops can be a pain (if that's what it is)! I assume that your solution keeps things quiet even when you're not touching a string. What device is the pickup plugged into? What device comes after that, if any? How are those devices grounded?

Doesn't really matter what I device I use with it. Mostly I use my Fishman Platinum preamp. But there is also a hum when my sitar is going direct to the PA or computer or amp or whatever. The little improvised metal ground strip solves it but I have to attach it every time I use the pickup and that is not very practical on gigs.

Using the ground switch on the Platinum doesn't help.

 

[bassfacer22]

Do you have another pickup to try?

I had hum before on some of my setups and now I can't remember which ones (I've tried a ton of pickups)

But I now use the full circle and there is no hum