Why is a 70hfe germ trans so much more gain than a 70hfe silicon??

[Stephen]

Seems strange but the idea of this is happening that I can get massive more drive with germs than silicon..


WHY IS THAT

[bwanasonic]

Seems strange but the idea of this is happening that I can get massive more drive with germs than silicon..


WHY IS THAT

Are you confusing clipping with gain? My feeble understanding is that Ge has a lower threshold (by half) of clipping than Si.

Kerry M

[petemoore]

  Probably beating on a dead horse where it's already been beaten...
  Why hasn't I seen a GE diode placed to clip at GE threshold, parallel to the diode in an Si transistor in a FF or other transistor clipper?

[brett]

Hi
In the FF, one side of the signal is clipped by the cut-off voltage of Q1.  In a Si that's a bit less than 0.7V and in a Ge that's a bit less than 0.3V.  (Note to self: must measure  actual values one day.)

Pete: unfortunately, you can't use a parallel ge diode coz all the base current will flow through it (Vf=0.3V) rather than the transistor (Vf=0.7V).  Hence the transistor will turn off and there'll be no signal.

You CAN affect the tone a bit by changing the DC operating point ("bias").  Increasing or decreasing the base current affects the emitter and collector currents, which affect the gain quite a bit.  In a fuzzface, adjust the R on Q2's collector and the "feedback" resistor in various ways.
cheers