http://www.heavyelectronics.com This thing is way beyond a compressor...almost a preamp on its own. Great secret EQ hidden in here somewhere...SKOL!
from their site:
For far too long, guitarists have had to choose between two categories of compression. Some are subtle and nuanced. They give the small amount of compression that is needed to level-out their playing, but have a hard time making a transformative effect. Others are squish- city and give a very effected type tone, but lack any sense of subtlety. Rarely, if ever, have the positive aspects of these two different paths intersected. This was our demand with the Sonic Oppressor, to create a pedal that could produce delicate compression but also had the capacity to become a seriously effective compressor with significant peak reduction and some smash to it. Beyond that, it had to be right all the way in between these too extremes.
Our optical compression circuit reacts very smoothly, so there's no "pumping" sound found commonly in highly compressive circuits. To achieve this with the maximum effect, we employed a vactrol rather than the "roll your own" method that many builders are using for their optocouplers. The Sonic Oppressor features a full-wave rectifying circuit (rather than half-wave) that allows for greater depth, and we believe, improves over-all performance on a wider array of frequencies. To reduce the noise often found in compression units, we've selected a very high quality Burr Brown Op-Amp from their OPA line.
The Sonic Oppressor has great headroom and it's been left intact with the OUTPUT control. The THRESHOLD and SUSTAIN work in tandem to define the response of the compression circuit. As they are adjusted the results are shown with the LED inside of the "All Seeing Eye". This LED is tied directly to the optical circuit and shows exactly when the notes you play are triggering compression (Threshold) and to what degree (Sustain). The GAIN switch adds significant boost to the circuit allowing the SUSTAIN knob to push well into Overdrive territory so that the Compression can be tied directly to that gain sound if desired. Join the Sonic Oppression!
I used a http://www.kingbeeguitars.com King Bee Guitars 'Haystack' Blackguard Telecaster, cocked, rocked, and loaded with http://www.riograndepickups.com Rio Grande, Muy Grande Tele Bridge and Buffalo Bucker neck pickups, http://www.drzamps.com Dr Z M12 amp, and a pair of mighty fine http://www.thedivinenoise.com Divine Noise tasty white coily and straight cables....yep!