Would this varitone circuit work?

[DrVenkman]

Just an idle thought that came to me when I was supposed to be thinking about other things....

The schematic labled 'Standard' is how the tone control is typically wired. My question is, would the 'Alternate' circuit work as a poor man's varitone (provided you used the right value caps)?

And don't be afraid to tell me this is stupid if it is, I won't be offended!

 

[line6man]

I really don't see something like that as being practical.

What exactly is a "poor man's varitone?"
A varitone control is simply a rotary toggle switch and several capacitors. You're talking a few bucks.

 

[slyjoe]

Agree with line6man - lose the pot, replace it with a rotary switch and various caps.

That isn't a standard tone circuit either, at least in most basses. Pot should be hanging in parallel off the input, wiper through cap to ground.

 

[DrVenkman]

You're right, I screwed up the 'standard' wiring.

Oh well. I was 98% sure this wouldn't work but posted it on the theory you learn by making mistakes.

 

[M0ses]

Wait.......would that create two different rolloffs?

 

[line6man]

You're right, I screwed up the 'standard' wiring.

Oh well. I was 98% sure this wouldn't work but posted it on the theory you learn by making mistakes.

Well, the schematic is fine, you just don't have an input shown.
Connect the output from your volume/blend/preamp/whatever to the output jack and you're good to go with that illustration.

It would work, but I just don't see it being practical to adjust.
The main tone control is like a master, and then the alternate further cuts the treble, but it can only cut up to the extent that the master tone is cutting.

For example, if you have the master tone rolled down just a touch, the alternate tone probably isn't going to have very much effect on the signal until you roll it way down so that the two caps are close to being in parallel to increase the capacitance.

With the range you would expect from each pot, you would probably just be happier with on/off switches, and in which case, you would just be happier with a rotary toggle instead.

 

[DrVenkman]

The reason I was thinking about this is one of the other threads about adding a multi-position switch with a selection of capacitors to go in place of the typical single tone cap. And to be clear, this isn't really something I'm thinking of doing it's more of a thought experiment to try and understand this stuff a little better.

Since capacitors in parallel add (and IIRC, it was line6man that corrected me when I got that wrong in the other thread - thanks!), I was thinking of this as a way to vary the capacitance of the tone cap.

Take a look at the revised circuit. When the second pot is zeroed out, does that in effect just change the total capacitance in the tone circuit? I think that's right.

What I'm much less clear on is what happens when the second pot is anywhere except zeroed out. Can anybody more knowledgeable on this take a crack at explaining it?

And just out of curiosity, what would happen if you ran two tone circuits in parallel with very different value caps?

Thanks!