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Re: OT: Bass Hum



redrum123 wrote:

> (sorry this is so off topic, but you guys are uberhelpful and 
>informative)
> 
> I've had my acoustic bass for not even a month, and there is a rather 
>severe
> noise issue using the pickup (it has a Fishman Classic4 preamp).  I 
>think it
> is a new problem, I don't remember having this level of noise on the line
> before.  I have the guitar running into an Ultra-DI box (by Behringer), 
>and
> then into an AB switch to my EDP.  I've tested the guitar by running it
> straight into my Tube Preamp, and even straight into a mixer, using 
>either
> an instrument cable or an XLR to 8th-inch cable, and the noise is
> consistent.  I can get rid of the noise by touching the guitar and the DI
> (or mixer or preamp), so the instrument should be capable of much less
> noise.  Also, I've found that if I touch the metal of the cable 
>connector on
> the guitar, the noise disappears.

For certain, you have a grounding problem. The real issue is, where is 
it *really* coming from. First, remove the instrument from your 
recording environment, i.e. take it over to a buddy's house and plug 
into their system, with a known good cable. IF the buzz disappears, the 
problem is probably in your studio, which is not really good news :-( If 
the buzz is still present, try several different cables. If it still 
buzzes, then the problem is probably in the pickup itself. Most likely, 
the ground shield to the preamp is fraying and coming undone, which 
means that it's not grounding properly. Or a solder to the ground sheild 
is coming loose, or is cracked.

If you are comfortable with a solding iron and have a steady hand, take 
the preamp out of the instrument, take it apart, and resolder the loose 
connection. Test it with a multi-meter to ensure connectivity.

If you don't want to hassle with trouble-shooting and repairing the unit 
yourself, take it to the *best* guitar repair shop in town and discuss 
the problem with them *in depth* including all the trouble-shooting 
steps you've taken.

Good luck!

D.G.