Modified guitar tone pot - similar to big muff?

[James HE]

I bought an old EKO acoustic guitar that has a magnetic pickup and passive volume and tone controls. I had made a post about using a cocentric pot to possibly have a parmetric eq or notch filter instead of the regular tone pot, but after some research, I think I will try something simpler like the tone control for a Big Muff. I've dowloaded the Duncan amps TSC and I've been playing around with that (awsome tool!) I'm imagining this being point to point just wired to the pot and lving inside the guitar. I usually give a low-mid cut on the eq on my mixer, so a heavy mid "scoop" is what i'm looking for (i think). If the tone control went from flat to a mid scoop that would be cool. Bass / treble on a cocentric pot may be preferable for more flexability, but the Muff circuit seems a little easier.

Since I will be pushing this tone control from the output of a magnetic pickup (on an acoustic guitar) what should I exspect? Will it even work? In the Duncan amps TSC what should I put as the source resistance?

Anyone ever done any special wiring with guitar pickups like this before? Is it feasable as a passive circuit?[/url]

 

[adamasd]

I did this in a guitar, Generally I do not like this tone control, I get very tierd of the always have the highs up and the lows down or the lows up and the highs down. The pretty much fixed midpoint drives me nuts after awhile. On this guitar though I have a seperate volume and tone control for each pickup, which makes this a pretty nice setup as long as you have both pickups on. Try the load at different source resistences and see how it sounds, its the only way you are going to know for sure. Different loads are going to make it sound different, so just start trying it out, its a simple circuit, cheap, and you will learn more about how loading effects the signal by jsut trying it out.

adam

 

[Kit]

If the tone control went from flat to a mid scoop that would be cool.

You could use a passive "twin-t" filter and and adjust the depht of the notch. Might be to narrow for a guitar "mid dip" though, dunno.

 

[clintrubber]

http://www.muzique.com/lab/tone3.htm

 

[James HE]

Thanks for all the help guys!

At this point I'm swimming in information. For this tone control I think I'm going to go attempt a bass / treble circuit. I'm still very confused about impedance issues and how the input impedance effect the load on a circuit. Actually I'm not sure in undestand the term "load" at all. Very basic stuff, but I'm learning as I go.

Currently I'm using a Duncan Performer acoustic pickup, I had it lying around and it's more balanced and cleaner sounding than the pickup that was on there originally. How can I measure the output impedance of the pickup? From what I understand it changes at different frequncies. Pretty lost here. While I try to figure this out, I think I'll attempt a passive DI, but that's another thread...

 

[PRR]

> output impedance of the pickup?

http://www.groupdiy.com/index.php?topic=170271#170271

 

[James HE]

Thanks PRR. I think I understand. There is a big peak at about 1M, but the Z is much much lower in the rest of the frequency range. If i'm using a simulator to get a sense of what values I wanted would it be more accurate to assume the average (say about 100k - 200k) or the highest at 1M.

 

[Kit]

The Z of a guitar pickup is somewhat complicatad to simulate, i think.
I recomend that you just wire it up and tweak it to taste.
That is, if the design is simple enough.