# Low parts-count DIY VCF...

- Site: Analog Industries
- Author: Chris Randall
- Date: 2006-01-26
- URL: https://analogindustries.com/2006/01/low-parts-count-diy-vcf/

If you're looking for a pretty easy DIY project, I just came across this low parts-count VCF that looks pretty promising, done using vactrols. [Here's the page.](http://www2.charlielamm.com/synth/vactrolvcf.php3) Everything is pretty easy to get, and I bet it could be done on veroboard or something without too much drama. I may build one this weekend, provided I can tear myself away from the two-headed hydra of coding and trying to get this comp out the door.

## Comments (3)

**inverseroom** (2006-01-26):

What are Vactrols? Where d'you get 'em?

**Chris Randall** (2006-01-26):

A vactrol is a combination of a light depending resistor (LDR) and an LED put into a small light-proof case. It's sometimes called a photoresistor or optoisolator. Small Bear has several to choose from.

-CR

**inverseroom** (2006-01-27):

OK, I've built a trem pedal using a cds cell and an LED, I get it. Thanks, man, I'll check that out!