FZ1 fuzz problems (LTSPICE, output is 1pV)

[ericohman]

Hi!

I'm a beginner with pedal electronics but since me and my friend bought a byoc kit we feel like there's nothing more fun and interesting than building pedals.

I started using ltspice since I read gaussmarkov's blog, his blog is also the reason I found this amazing forum. I've did a schematic in LTspice of both the rangemaster and Maestro FZ1 fuzz and they both show the same problem when I run a simulation. I get around 1 pV at the Output and I have 100mV ac sine for the input. Will this mean that if I build this pedal it will have the same problem, and why is this happening?



I got the schematics from http://fuzzcentral.ssguitar.com/ (both the fz1 and rangemaster)
IMPORTANT! I use AC128 transistors because I couldn't find the original FZ1 transistors inside LTspice, I use potentiometers that I found on gaussmarkov.net

If you feel like helping out I have made a .zip file which contains all the files, links to schematics and LTspiceIV that you will need.
I'm a beginner so I might have gotten the Input and Output wiring wrong.

Link to fz1.zip:
http://dreamfield.dyndns.org/_eric/guitar/diy/fz1/fz1.zip

Best regards from Sweden

[Sir H C]

My guess is that you will have to play with the model parameters to get this to work.  It is the transistor leakage that makes the circuit bias correctly, so if you do not have the leakage ballpark right then nada.  I forget the parameters (IIRC it is the Gummel-Poon model for bipolars) but something should be there for leakage.  Raise it up so that it works.