Tone capacitors

[Twigman]

OK can someone explain tone capacitors to me.
How does the value of the capacitor uF affect the signal and thus the tone?
The voltage rating of the capacitor (100V, 600V etc) - how does that affect the effect of the capacitor?
The composition of the capacitor (oil and paper etc) - how does that affect the effect of the capacitor?

I am building a passive pbass and although I already have a couple of capacitors that were sold to me as bass tone capacitors I am unsure as to which to use or if I should use another different capacitor.

So you boffins can you explain how all the variables relate to the signal so I might make an informed decision.

thanks

[Beer of the Bass]

I would say that the only important parameter for a tone control capacitor is the capacitance. The value affects the frequency above which the tone control starts sending signal to ground, with larger values starting at a lower frequency and thus sounding darker as the tone is turned down. This is worth experimenting with to find the value that does what you want.
The voltage rating is unimportant here, as it is just a recommended maximum at which the capacitor can be used. Guitar signal is in the range of a few hundred millivolts, so any available voltage rating is fine.
Capacitor composition can be a touchy subject on forums, leading to interminable multi-page "mojo" versus "science" threads. I have yet to hear anything to convince me that it makes a difference in a tone control, when comparing between capacitors of equal value.

[chris_b]

Google is your friend....


[url="http://forums.fender.com/viewtopic.php?t=23438"]http://forums.fender...pic.php?t=23438[/url]

[brensabre79]

great link above. Although I would say that the noticable effectiveness of the expensive PIO capacitors is quite little. And beware of those really very expensive ones from the 60s that pop up on eBay.
Voltage doesn't really matter on a bass, 100v tolerance would matter on a 240v circuit - i.e. it would melt! but not for a passive bass.

So get some cheapo Poly ones (like Fender do these days) of different values and see what suits you best. A lot depends on the pickups you have, and the tone you want in terms of finding the sweet spot frequency to roll off.

[lazybones]

go with the modern capacitor first ,i bought a oil in paper capacitor and couldnt live with it,thats when i realized the reason things change is that things get better..