High-pitch hiss when tone knob is turned full open on P-bass....

[Fender4Me]

My P-bass has a high pitch hiss that can be heard when I turn the tone knob to full treble. Would that indicate a bad cap on the tone pot or something else? Thanks

[walterw]

a passive P-bass?

that hiss is way more likely to be coming from somewhere else and getting masked when the tone knob is turned down.

[Fender4Me]

Yes, passive. Thanks!

[loinmute]

I don't think tone capacitors exhibit that type of behaviour when they fail.
Maybe a shielding/grounding issue.

[Stealth]

It's a shielding issue, certainly. Shielding the pickup and electronics should eliminate it.

[Fender4Me]

Ok Thanks guys. Its really not that bad so, since it is a vintage bass, I will not do the shielding. I play it mainly with the tone control at about 10-20% anyway.