Si Fuzzrite

[hohlamazoo]

I finished a Si Fuzzrite a while ago and it just doesn't sound right to me.  It seems to be missing the trademarked characteristics which make it identifiable. I used the 2N2222 transistors with hfe around 300.  I noticed a lot of other people suggest hfe ranging from 100-150.  Is that my problem?

Also, I have access to a large amount of 2N5551's and 2N5550's.  Both have gain listed in the recommended range, but I never hear of them be a suggested component.  Is it because of their high voltage rating? 

[jrod]

Which schematic or layout did you use?

There is a 22K resistor missing from most si FuzzRite schematics which adds to the trademark trebly sound.

I think those 2N2222's should be just fine and would bet you wouldn't here much difference if any to the overall sound. The 22K resistor will make more of a difference if it's missing.

[hohlamazoo]

Here's the schematic:

http://fuzzcentral.ssguitar.com/schematics/fuzzriteschem.gif

[John Lyons]

I would go with some lower gain transistors and the 22K.
The 22k cuts a good bit ow low end (a good thing) and also alters the Attack knob
settings in the middle ranges. I'd put it on a switch to get the best of both
settings.

[hohlamazoo]

So, where do I install the 22k?  and will the 2N25550/2N5551's work (they're lower gain NPN silicon)?

[jrod]

Have a look at this germanium version: HERE

The 22K resistor goes to ground between the fuzz pot and the 2nF cap to Q2's collector.

[hohlamazoo]

I'll give it a try this weekend with the 2N2222's.  If it still needs adjustment, I switch transistors.  Thanks

[LucifersTrip]

I'll give it a try this weekend with the 2N2222's.  If it still needs adjustment, I switch transistors.  Thanks

I did use the 2N5550's with very good results....and also 2SC1815's.

...and I actually put a pot (20K, I believe) in place of the 22K (w/ a small cutoff resistor)

btw, to get 350K and 33K for the pots, use 1.2M and 100K resistors, respectively

good luck

[Electron Tornado]

Here's the schematic:

http://fuzzcentral.ssguitar.com/schematics/fuzzriteschem.gif

That schematic is missing the 22k resistor to ground that is on the original Fuzzrite. The link below shows the schematic with the resistor:

Have a look at this germanium version: HERE

The 22K resistor goes to ground between the fuzz pot and the 2nF cap to Q2's collector.

I also put that resistor on a switch. Use transistors with gains around 100 for a better sound. Higher gains don't sound as good.

[hohlamazoo]

Well, I left the high gain transistors in, but added the 22k resistor.  It sounds much more authentic now.  I'm going to experiment with the lower gain transformers on the next build.  Thanks for all your help.