big muff basics

[JasonG]

Ok , so I just learned about transistor circuits and noticed that the big muff is a common-emiter type circuit. In the book I am reading ( TAB electricity and electronics a great book so far ) they have a common- emitter with a resistor and a cap on the emitter the cap is a bypass cap which helps stableize the circuit. But on the big muff they have a cap (500p) on the collector and a resistor (470k) that is parallel to it. Is that also a coupling cap ? Also is the cap after the sustain pot also a bypass cap or is it a coupling ? 
                                                                       Thanks !

[Skreddy]

The 500 pf and 470k are negative-feedback components.  The cap reduces noise, and the resistor reduces gain and stabilizes and biases the transistor.

The cap after the sustain pot is a coupling cap.

[soggybag]

on the subject of the Big Muff. The sustain knob sets the gain of the first transistor. Why does this create more sustain and compression?

[Seljer]

I'm not really good at this kind of stuff but isn't the sustain control just a regular volume control after the first gain stage (which I presume gives a very nice amount of gain) and before the 2 clipping stages which obviously add a nice amount of clipping.
The sustain and compression are just there from the amount of gain and clipping thats happening.