Variable cap for tone control?

[DrVenkman]

Just curious about this. I see people changing out the capacitor on the tone control for different values, but I haven't seen anybody go with a variable cap on the tone control. Has anybody tried that? What did you think of it?

[line6man]

You mean one of these?

[NickInMesa]

Originally Posted by DrVenkman

Just curious about this. I see people changing out the capacitor on the tone control for different values, but I haven't seen anybody go with a variable cap on the tone control. Has anybody tried that? What did you think of it?

There are setups with a rotary selector. Look it up.

It's a fun DIY if you're bored

Look it up, it's somewhere. But you can figure it out yourself of course.

[NickInMesa]

Originally Posted by line6man

You mean one of these?

That's for if you want to build an old-school AM radio.

[DrVenkman]

D'oh! Messed up the search the first time around. Now I understand.


Nothing to see here, move along......

[line6man]

Originally Posted by NickInMesa

That's for if you want to build an old-school AM radio.

Exactly.

They are far too large to be used in an instrument.
They also usually have very small capacitances, and the range of adjustment is relatively small as well.

[i_got_a_mohawk]

If you want to change the cap value, you could just use a rotary switch with some different caps connected to the ground.

(heck, chuck in an inductor and use it as a notch filter)

[grue]

Or you could put in a push/pull pot which switched between two different caps.

What you're describing is almost like a parametric EQ, though. I bet you could find an active preamp that did something like that.

[Bigjohn]

I believe the capacitance of those air core tuning caps is very small. I don't think it would work practically.

[slyjoe]

Practical only if you use 100 of them to get to a 0.047 uF cap.