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DIY Stompboxes => Building your own stompbox => Topic started by: richon on June 22, 2009, 10:43:51 PM

Title: hybrid Fuzz Face (which first , Silicon or Germanium)
Post by: richon on June 22, 2009, 10:43:51 PM
I'm building hybrid Fuzz Face

which transistor first , Silicon or Germanium??
Title: Re: hybrid Fuzz Face (which first , Silicon or Germanium)
Post by: John Lyons on June 23, 2009, 12:36:45 AM
Use the germanium in the Q2 position.
All the fuzz happens there and you will get
more out of the germanium's sound there.

john

Title: Re: hybrid Fuzz Face (which first , Silicon or Germanium)
Post by: brett on June 23, 2009, 02:04:27 AM
Hi
I thought that Q1 is where the asymetric clipping happens (b to gnd is only 0.3V).  It is also the device that lowers input impedance (via low hFE).  So wouldn't you go Ge for Q1 for tubish-ness and bloom?
cheers
Title: Re: hybrid Fuzz Face (which first , Silicon or Germanium)
Post by: John Lyons on June 23, 2009, 05:59:04 PM
I'm just going off audio probing results and with Joe Gagan's Easy face which is a hybrid with
a SI transistor in Q1. I just assumed that Q2 gets hit harder an germanium would come into
play there more than SI for a woolier sound.

John

Title: Re: hybrid Fuzz Face (which first , Silicon or Germanium)
Post by: Derringer on June 23, 2009, 06:04:12 PM
socket both transistors and see which sounds best where


but otherwise ... the Lower gain Q is what typically goes into Q1


but the only rule that applies here is that there are no rules
Title: Re: hybrid Fuzz Face (which first , Silicon or Germanium)
Post by: liquids on June 24, 2009, 10:53:16 AM
To my ears, and to my surprise, if you have to pick one, you get more mileage with Q1 as Silicon and Q2 as Germanium than the opposite.
Title: Re: hybrid Fuzz Face (which first , Silicon or Germanium)
Post by: mac on June 26, 2009, 12:30:32 AM
I prefer Q1 Si for two reasons,
1. most of the fuzz happens at Q2. The dist of Q1, if you take the output from there, is soft.
2. No thermal run away, and you can use leaky Ge at Q2. Finger heat Q2 and see what happens at Q2C, a very small deviation.
Once bias is set, temp will be no longer a problem.

I also use a 47k to 68k at Q1C.

mac