[sdiy] CV wah-wah with gyrator

[Aaron Lanterman]

On Mon, 1 May 2006 gte111x at mail.gatech.edu wrote:

> Aaron, I'm attaching my schematic with this email I've been working on 
> implementing this on the bread board last week, and it SEEMS to be

Jonathan - this is very interesting. The use of the gyrator to replace 
the big bulky expensive inductor is clever. (I think Paul Schreiber does 
that with his version of the Moog filterbank, so you're in good company).

I'm ccing The List on my response. Listies - I've Jonathan's draft here:

users.ece.gatech.edu/~lanterma/wah.pdf

(Remembger, this is a quickie sketch.)

(I'm just handing out direct links now, I've stopped trying to keep up 
with the page with all the links in one, since they're temporary anyway).

Jonathan - when you draw the final schematic, you'll want to chance your
symbol for the Vactrol, as what you're using is nonstandard. Typically
you'll see a circle with a resistor in it and a diode in it.

> working, I couldn't get a chance to check its result with my guitar but 
> with the sawtooth wave input, it generates some sound with the same 
> freq.

Ah - but what do you _hear_? There's a couple speakers floating around lab 
with a 1/4" adaptor, you can hook a couple of allegator clips to it real 
quick and take a listen. For your CV source you can just grab one of the 
lab supplies and sweep the voltage.

Do you see the waveform change shape on the scope as you twizzle the CV?

> I'll be done with my finals by this Wed. and continue to work til Friday.  I
> hope to finish it all soldered by then.

Excellent. Yes, put it aside for a bit and focus on studying for your 
exams. You can pick it up later.

> Once again thank you so much for this fun!!!! class!

Thanks for your kind words!

- Aaron

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Dr. Aaron Lanterman, Asst. Prof.
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