NEUTRON - MUTRON 3 Help with the filtering!

[marshal2107]

I need a little help here on the GGG Neutron (Mutron iii work alike). Here's the link to the GGG site http://www.generalguitargadgets.com/effects-projects/filters-envelope/neutron/ .

Leds move around with the envelope, but no sweeping happens.  I have tried openening up the ldrs, and y try to sweep them with a flashlight, but I don't get any frequency sweep.  If I give too much light It starts buzzing or oscilatting around 10k.  In a softer flashlight move, all I get is a variation in volume. Like it's working as a tremolo instead of a filter.  Also with the less pointing to the ldrs, I don't even notice a variation in volume.  This with the schematic " up position". The actual behaviour is that when I strum the light goes off for a glimpse of an eye, whether that's right for up or down position I don't know yet.

Any clues?

Thanks!

[Kevin Mitchell]

It's likely just your optos. The LDR's resistance aren't hitting the range the MUTRON circuit is designed around.

This sounds like the same problem I had with my home made optocouplers. I ended up using a pair of VTL5C3 optos and got it working.

What are you using? If they're homemade optos, what LDRs are you using? Are they shielded from external light? If not, they should be.

-KM