De Humming my Stambaugh

[Aaron Brenton]

Hi all,

I have a beautiful Stambaugh custom I got from a fantastic member here on talkbass around last Spring. I love this instrument, and this problem only just popped up. There's a bit of hum when the instrument is in passive mode and still semi present when I am playing it active, which is most of the time. The control cavity is copper taped and when I had a guitar tech look at it he said that everything looked okay. The bass IS almost 20 years old and I don't know if Copper tape is supposed to be replaced or if I should do a copper paint type deal. I noticed that it gets better when my hands are on the strings and it comes back when I take them off. Any help would be much appreciated! I can send some pictures later today.

 

[RSBBass]

You may simply be in a place with a lot of electrical interference. No bass is 100% shielded. Properly applied copper tape should last close to forever.

 

[Aaron Brenton]

You may simply be in a place with a lot of electrical interference. No bass is 100% shielded. Properly applied copper tape should last close to forever.

Oh okay, yeah, it covers the whole cavity and all the wires are soldered/properly covered. Thanks, I’ll work with my volume on my amp and my preamp to get a good clean sound.

 

[Turnaround]

It sounds like your bass is normal. When you are not touching the strings the electrical noise from your body is being "heard" by the pickups. Once you touch the strings you ground yourself to the bass's ground which drains your body noise. It's working properly.
To totally eliminate body noise when not touching the strings you will need to completely shield the pickups, which will mean that they won't see the string vibrations either. Probably not what you are looking for.

 

[Aaron Brenton]

Thank you all very much! I should also mention it usually only happens when I’m plugged into my headphone amp.

 

[MrLenny1]

Sounds like an issue with that amp.

 

[Aaron Brenton]

Sounds like an issue with that amp.

Yeah, it could be. It's actually a DSM Humboldt Bass Station, so it's also not grounded to anything. And the headphones kind of create another connection between my head and the preamp and the bass.