Here's the textual explanation of what kind of processing Klon does to the sound quoted from La Revolution Deux site. It pretty much complies to what I see from the brief analysis of schematic. "It truly is an original circuit which utilizes some great ideas. The Klon basically splits the signal into 3 parts - highs, mids and lows - the mid and low sections are "eq"ed and the highs are run through an overdrive circuit before the three parts are mixed back together again with an opamp mixer section - which is run off a charge pump supplying a dual polarity supply to stop any further clipping taking place. As the gain is increased the level of mids and lows present in the final mix is reduced, this is controlled via a dual taper pot which simultaneously increases the overdrive gain and reduces the level of the mid and low sections. The tone control is an active treble boost/cut allowing the level of the highs to be adjusted to taste." http://revolutiondeux.blogspot.ru/2008/01/klown-centaur.html I've done a simple mod to my SD-1 which made it sound really sweet. I also wondered why Boss can't do it rihgt at the factory. After many years of third party mods Boss got the idea and will deliver the modded SD-1 (as well as BD-2 and DM-2) soon to the market as a part of their new Waza line. I know I'm in a minority but I never heard a good sound from my Soul Food. I've no idea what EHX has done to a good cirquit. Probably it's a cirquit mod or SMT or bad component quality or altogether. I failed to find the SF schematic on the Net and lazy to do cirquit tracing myself just to find what's wrong. I've just assembled my Silver Pony and going to test it against the Soul Food and one more clone of mine tonight.