Hi.  I'm playing with some bazz fuss circuits, and I was wondering....Is there a general rule for how low (in voltage terms) the collector of a simple emitter-to-ground transistor (or Darlington pair) can go?  (ie like the bazz fuss transistor or Q1 in a fuzzface)

For that matter, how close to the supply voltage can you go?

I presume that the 1.2 V (double junction) base-emitter difference in a Darlington gives the Bazz Fuss some extra headroom on the low side (legroom??).

I'm kinda thinking out loud here...Anybody got any decent rules-of-thumb?

thanks

Till you get 'undesirable' gating?  That's the 'ceiling/floor' I use for setting max and min collector Voltages.
 I think it can go pretty high...like 7+volts, of course your pos[?] swing will be reduced the higher the Collector bias voltage is set

I'm pretty hazy on this, but I've got it in my notes somewhere (though God knows where!).  I think that the base collector junction needs at least .7V - 1V across it for normal transistor action to occur.  

I'm sure someone (probably RG) will come along and give you the real answer!