New project: Voltage Controlled Filter

[dislocations]

Hi,
Sorry if this is a bit vague
I'm looking round for a schematic for a VCF (easier the better). In short I want a LPF that is controlled by a oscillator outputing sine, square, sawtooth waveforms. I want to be able to control the rate of the oscillators.
Any advice would be great!

 

[poor mystic]

Hi
do you want the filter to be controlled by a DC voltage, or by the rapidly changing signal from an oscillator?

 

[dislocations]

By the oscillator I think

 

[poor mystic]

So the frequency filtered will rise and fall as the voltage of the oscillator signal rises and falls?

 

[dislocations]

Yeah, thats sounds right!

 

[poor mystic]

We need to know a bit more yet, please. Can you tell us

1) the signal which will drive the filter, please. We need the frequency and voltage of the signal.

2) what frequencies the filter must handle?

3) It might be helpful to know the application.

Mark

 

[dislocations]

This is roughly what I'm looking at building..........

http://musicpcb.com/pcbs/gristleizer/

 

[(*steve*)]

Check that page, they have the full circuit diagram for it.

They don't seem to publish the PCB layout which makes things a little more tricky.

 

[poor mystic]

A VCF is not really all that easy a thing to design,compared to a lot of other circuits. Why change what is already a known-to-be-working circuit? Of course if it's an exercise in learning electronics design - well fair enough, but it's not an easy, beginner-friendly kind of project.
A google search brought up several useful links, including one to a thread on a forum in which several contributors have built 'gristleizers'.
Mark

 

[jackorocko]

I got a guess why, the cost. $14 dollars for a PDF file??? I have paid that kind of money for a PCB with instructions and a BOM before.

edit: I guess the cost is for the board. The way the site was setup it really looked like they wanted to sell you a PDF. I'd by the board and make it, looks simple enough

 

[dislocations]

Thanks for the advice all!!! Considering buying the board after all.