• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join freeLog in
    Want zero display ads or expanded classifieds tools? Compare plans.

Annoying Hiss

I have a Fender MIM jazz bass that has an annoying high frequency hiss in it when I am not playing. When I turn the tone knob all the way off it goes away. The has shielded pickup cavities. Any ideas I can do to fix this?
 
Hiss is generated by active circuits, and normally occurs in the preamp (input) stage of the amp.
The level of the hiss depends on both the gain setting of the amp, and the impedance of the source.
The source in this case is the bass. The tone pot affects the bass output impedance at high frequencies

If everything is working normally, the gain of the amp may be set too high. It is basically a matter of
signal to noise ratio.

Is the bass ouput level good? Are the volume pots set reasonably high? And the pickup height set
properly?

If the bass output is weak, the amp gain will have to be set abnormally high, and the input noise (hiss)
will be amplified.

-