Upper Octave Fuzz made from J-FET + (leaky)GeTr + SiTr

[Koji Kusanagi]

Last year I made some germanium Fuzz Faces, so I have a lot of leaky germanium transistors left behind.
After thinking about their effective use, I made a BazzFuss-like fuzz prototype like this.
Large idle current makes its leak less noticeable!



Q1: 2SK369GR: gm = 22mS
Q2: 2SD187: hFE=61, leak=230mA
Q3: MPSA18: hFE=1200

C1,C2,C4,C9,C10: Film, C3,C6,C8: Ceramic, C5,C7: Chemical BP, C11: Chemical

Here's some demo movies.
http://www.youtube.com/my_playlists?p=F8A1EC2FAAC11B56



3 knobs in demo movies are (L to R) Volume, Fuzz and DUMMY
Dummy knob derived from old pedal, because this is recycled enclosure of old one.

This is a dual mode fuzz. The "Mode" switch toggles between 2 modes; upper-octave and dark-boost.
Upper-octave mode: J-FET boosted Ge-Si hybrid buzz box
Dark-boost mode: J-FET boosted Ge-Si hybrid Bazz Fuss + another boost

The FUZZ VR controls not only gain but tone/texture.


This prototype has some known issues:

• While upper-octave mode does not so loud, dark-boost has way tooooo much gain (I had blown out one of my amp).
• 
  
  
  
  • SW can be DPDT. In case it points R6, other pole should add some R or VR between Emitter of Q3 and GND, to lessen the gain.
  • Asymmetric clipper diodes can be replaced by a pair of Si and Ge.
• R3 may be too small (for battery).
• C1 may be too large for guitar. It's C/O freq is around 1Hz.
• Circuit itself is quite easy to build, but 2SK369GR and 2SD187 are very tough to get even in Japan, needless to say in other countries.

By the way, this circuit still has no name.
I'd appreciate if you could give canditates.

Thanks.

[faptdivers]

Karma Hunter , Upper Flooractave , Octavepuss , Leaky Dummy , Prototypee Octavee.

[Koji Kusanagi]

Karma Hunter , Upper Flooractave , Octavepuss , Leaky Dummy , Prototypee Octavee.

Wow thanks, they all are somewhat meaningful, especially the first one.

[Koji Kusanagi]

5 audio demos are available now. I don't know how to play better

1 of 5: http://twaud.io/qc3H - Lead tone, 3 different mode/PU settings, Fuzz=10.
2 of 5: http://twaud.io/qc3P - Lead tone, Bridge Pickup, UpperOctave mode, Fuzz=4.
3 of 5: http://twaud.io/qc3v - Playing some riff, Bridge Pickup, DarkBoost mode, Fuzz=6.
4 of 5: http://twaud.io/qc3w - Playing some riff, Bridge Pickup, UpperOctave mode, Fuzz=4. 
5 of 5: http://twaud.io/qc3y - Code stroking (like shoegazer), Bridge Pickup, UpperOctave mode, Fuzz=7. 

[Koji Kusanagi]

Oh, video URL was wrong.
That should have been: http://www.youtube.com/user/kojikusanagi#grid/user/F8A1EC2FAAC11B56