Demeter Fat Control

Looking for a mid-range frequency booster? This one's apparently really good at it. Schematic and discussion on FSB here.

Demeter Fuzzulator

Here's an interesting opamp-based fuzz from Demeter for Fuzz Friday. I imagine other dual opamps can be used in place of the LF442, so socket and experiment. The trimmer in the original seems to be set at 2.5k. Schematic can be found here.

Demeter Tremulator

Here's a great sounding tremolo circuit from Demeter–the Tremulator. It's an optical trem, using a VTL5C1. That part can be replaced with an LED and a LDR (600Ω on/50M off) combo. Also, the diodes used in the originals are 1N5229 4.3v zenners, though you can use other zenners up to 5.1v. Here's the schematic for reference.

Demeter Compulator

Here's a really nice optical compressor from Demeter. It offers vintage studio compression that's very transparent and a fairly simple simple build as well. The trimpot sets the gain of the compressor's preamp stage. If the signal is distorted, turn down the trimmer till it's clean. Here's the schematic for reference.