High Pitched Whistle '78 Jazz

[jakenewmanbass]

I have a 78 Jazz with Symour Duncan pick ups (on when I bought it) they have 3 little white switches presumably to boost signal at various frequency ranges.
I have recorded with the bass, but have a more major project coming up and would like to eliminate the sound.
It could be an earthing issue as the sound almost disappears if I hold the strings, or if I touch the metal strip where the controls are.I know nothing about circuitry and would appreciate any suggestions from anyone that may have an idea (is it common etc...)
Or failing that suggest somewhere I could go with it (I'm just outside M25 south west of London, am in London working a lot)

Help would be greatly appreciated

Jake

Edited January 30, 2008 by jakesbass