calavera trimpots

[jimmy]

hi all

in my search for a smooth distortion tone i have built tim escobeos calavera and i have no idea what to set the trimpots to.

help?

[gez]

I designed a similar circuit a while ago based on the same principle.  I can't speak for Tim, but my own reason for using trimpots was to bias the outputs of each inverter in the centre (using a divider, the bias was WAY off with some chips I used, which caused gating problems - trimpots sorted this out no problem).

My advice would be to use a multimeter and measure the voltage at the outputs, adjust the trims till the outputs are at about half the supply.  Of course there's no reason why you can't bias them slightly off-centre for asymettry, though I found this to produce harsh intermodulation distortion if the DC bias is too off.

[Tim Escobedo]

Stick the trimpots around halfway with the gain all the way up. You should be able to hear some guitar coming through, though it may sound sputtery or have little sustain. Then fiddle with each trimpot until it sounds best. Then turn the gain way low and adjust the trimmers again for best sound. Should be about done. The settings will vary from chip to chip.