"ToadWorks Mr. Squishy is an analog compressor pedal that combines purity of tone with tight, punchy squeeze-on-demand. Mr. Squishy has been tested with a wide range of amplifiers, including tube, solid state and hybrid, and it delivers the goods every time.
ToadWorks Mr. Squishy provides great compression without oppression, remaining transparent enough that you never lose the original tonal qualities that made you love your axe in the first place. For years, guitarists have sought a natural sounding compression that did not diminish their tone, and ToadWorks has delivered.
Don't you just hate when you kick on the compressor, and your guitar sound changes? Compressors aren't supposed to do that. ToadWorks Mr. Squishy is the anti-compressor - your tone stays crystal clear and unblemished.
Mr. Squishy provides plenty of squish where you want it, and none where you don't. The Gain, Squish & Level controls allow you to compensate for all manner of differences between guitars, pickup types, etc. Mr. Squishy has a nice, tight attack, and a long, slow release, giving you the best of both worlds. Mr. Squishy won't distort unless you want it to; there is no buffer, the Op-Amp can be overdriven, but that's what the Gain control is for. And when you listen to the sound clips, notice that the Level is always around six... want to guess what happens if you turn off the Squish, crank the Gain, and set the Level at 10? A very serious clean boost that will overdrive your amp's input. Yes, that's right - Mr. Squishy can double as perfect clean boost, with power to spare."
And here's a demo of the Mr Squishy in action:
Well, thanks to phibes and aegert over at freestompboxes.org the Mr Squishy has been gutted and here's the schematic: http://www.box.com/s/194dc32665d393373c68
As you can see the circuit is a tuned variation of the original Dan Armstrong "Orange Squeezer" opamp/jfet based compressor:
This type of compressor is a good option if you are looking for a more transparent compression with a less evident "squish" on the tone (a quick attack/release time). You can get some distortion caused by overloading the input and forcing the attenuation jfet to clip but overall this compressor design works well for it's simplicity.
For further reading here's the freestompboxes.org forum topic: http://freestompboxes.org/viewtopic.php?f=7&t=16760