Demeter Fuzzulator

This design was pretty awkward to get down to a reasonable size due to two opamps, a trimmer and mere ten diodes on board. I'm not liking the asymmetry, but i still fitted it in a quite compact size. In the demos, this one sounds like a nice and creamy opamp fuzz..

From Demeter site:  "The Fuzzulator was designed to be a fuzz with focus. So many fuzzes sound cool but get lost in the mix because they don't have a clear sound image. I solved that problem with tonal pre emphasis before the sound hits the distortion generator. The unit also has both LED or germanium diode distortion available at the flip of a switch." - James

Demeter Fat Control

Info from Demeter about their original:

The Fat Control is an on board guitar mid boost/buffer which includes a wide variable gain mid frequency power booster control and a built-in low impedance buffer that has been installed into a steel stomp box. The Fat Control boosts a wide mid frequency range for a more distinct natural musical frequency boost than all other mid controls. The frequencies selected give your guitar the best response and sustain possible.

Demeter Tremulator

Requested by a few people.  This uses a vactrol but it might work with a roll your own LDR if you want to give it a try.  The spec of the VTL5C1 is 600 ohm on resistance and 50M ohm off resistance.

If you would prefer a tempo rate LED instead of a standard always on LED then take a feed from IC1 pin 7, and you will need to include a limiting resistor in series.  I didn't add this to the board because it would add an additional column which I didn't want to do if the feature wasn't required by most people.

Info from Demeter:

A hybrid of vintage sound and state-of-the-art quality, the Demeter Tremulator is designed for years of trouble-free operation.

Designed to emulate the classic Fender tremolo effect (or vibrato as it is often referred to), the Tremulator features "lopsided" amplitude modulation with a rounded off traingular modulant waveform. Suffice it to say, the Tremulator sounds like the classic effect found on many vintage amps, but with less noise and hum and a greater range of speeds and depths.

Operation is fairly straightforward. There are two inputs on the front side of the unit: a 1/4" input jack on the right and a 1/4" output jack on the left with a battery-ground switch on the input jack.

There are two controls on the unit: Depth and Speed, plus a footswitch to bypass the effect, and an LED to indicate effect operation. On the side there is a trim pot to set the bias for the optical unit.

Depth affects the amount of amplitude modulation on the signal or the amount of effect. The tremulator design incorporates a small amount of gain (approx. 1dB) to allow for proper "tremulation." Also, by turning the Depth all the way off, the TRM-1 will function as a low noise volume boost. It's low-impedance output allows it to act as a line-drive, eliminating signal loss on long cable runs.

Speed increases and decreases the frequency of the low-frequency oscillator, enabling you to time the effect as desired.

Trim pot sets the bias of the optical tremolo unit. It effects the signal on and of time ratio. Turned up to height it will squeeze the signal, low it will loosen it. The unit comes preset to Ry Cooder's preferred setting.

Youtube demo showing good examples of the range of sounds from the pedal:

Demeter Compulator

Info from Demeter about the original:

"The Compulator was born after I solved an engineering problem of biasing an optical unit with only a single 9V battery. I had always loved the sound of optical compressors and designed and manufactured tube units in the pro audio market for a number of years. I wanted to make a pedal, but it took years to come up with a method to do it the right way. The result is the Compulator, winner of Guitar Player Editor's Pick Award and the only compressor that does not suck away your tone." - James

The sound of classic studio optical compression of the 60's and 70's at your feet! The first compressor pedal not to suck the life out of your tone.

Operation is fairly straightforward. There are two inputs on the front side of the unit: a 1/4" input jack on the right and a 1/4" output jack on the left with a battery-ground switch on the input jack.

There are two controls on the unit: compress and volume, plus a foot switch to bypass the effect, and an LED to indicate effect operation. On the side there is a trim pot to set the overall gain of the unit.

Compress affects the amount of gain reduction (compression) of the input signal. Turning this clock wise will give you up to 30dB of gain reduction (depending on input gain). Please note that the Compulators max gain is 26dB (see Trim Pot) so in some circumstances if your instrument is very hot you could achieve less than unity gain if you turn up the compress knob too much.

Volume increases and decreases the output volume of the Compulator. Use this for level matching between the effected and unaffected signal.

Trim pot sets the gain of the compressor's pre-amplifier. If distortion occurs turn this down until the signal is clean. The unit is set at the factory at 20dB of gain which is perfect for most instruments. If you have weaker pickups or want to push the envelope turn it up to its max gain 26dB.

Update:  There was a missing cut between the top of the 619R and the 10K, so if you've been having trouble with this layout then give that a try.  Layout updated below.