Best Fuzz Face board for experimenting with my russian PNP's

[bassybeats]

So I have a crap ton of PNP (and NPN) Russian germaniums. And trying to find a good base pcb where i can put trim pots all over it and swap out and try out all these transistors. Attempting to breadboard one out but don't know which is best.

thoughts?

[mattlee0037]

1776 effects has a 5 o clock fuzz with onboard charge pump that I used with my Russian PNP's. I really enjoy it!

[bassybeats]

Cool will look into it. Their echo looks nice too and their shipping has come down.

I have had less success with the NPN's more than the PNP. are the low gain ones better suited in a 3 transistor arrangement..?

[davent]

I've been playing with low gain PNP's in a Darlington arrangement for Rangemasters as outlined by Small Bear.

https://www.smallbearelec.com/HowTos/BreadboardGeDarlingtons/BreadboardGeDarlingtons.htm

Also built one stage of this circuit (with plastic emitter caps 2uF total so i can swap power leads and use with PNP's or NPN's) for taking measurements and listening to/audition the various GE's hanging around.


thread http://www.diystompboxes.com/smfforum/index.php?topic=105551.0


dave

[murdog47]

This one 

[jrod]

LOL I second this^^^^

Beavis Audio has a great breadboard layout for the Fuzz Face in his Beavis Board project guide.

dave

Where did you find the green sockets on the right? Those would be great to use for RG Keen's Ge test circuit.

[davent]

 Sounds good to me, spring actuated and 0.100" pitch. Digikey #277-1796-ND


dave

[jrod]

Right on! Thanks Davent!

[bassybeats]

Yeah I've breadboarded up one of each of the Beavis ones (one PNP and one NPN).

Made all the resistors trim pots and a couple of cap options, but what other variation can i use? a 100K vol swap somehow. other things I can switch in and out?

[jkokura]

I think you're coming up against something really common with the Fuzz Face - there are really only a few parts you can really adjust in the circuit. The real key with it isn't the values of anything, or adding/subtracting anything, it's the transistors. The different transistors sound different, largely because of their performance rates and HFE, but also because of their relationships with the other parts.

Good Fuzzes are really about good transistors. The other parts are just there to get the best (or worst sometimes) performance out of the trannies.

Jacob

[jrod]

I came across a thread that forum member Gus started over at DIYSB about a different way to bias a Fuzz Face that I am interested in trying.

Gus has suggested biasing the circuit by using a 5K trim pot on the emitter of Q2 instead of changing the 8K2 on Q2 collector.

I will see if I can find the thread and I will link it here because he has a new way to bias the circuit. IIRC you add a 1M in parallel with the 100K feedback resistor.

Also, in the thread member mac posts a schematic of how he biases the circuit that looks interesting.

After you read their ideas and then go back and read RG Keen Technology of.... article it makes sense. Anyway, I'll try to find what I am talking about.

It might be something to try since you have the circuit on the breadboard.

Ok, found it! But, realized it is for biasing Si transistors. Don't see why it work with Ge though.

http://www.diystompboxes.com/smfforum/index.php?topic=104818.0

Gus posted his schematic with the 5K trimmer I was referring to.

[bassybeats]

I've come across a few good options so far. Mostly PNP. I'm finding that ALOT of the NPN Ge's are very fizzy, anyway to smooth them out?

Also some of the PNP Russians IT408V are huge and in the hfe 70-90 range, but display no fuzz at all, barely even boosts the signal.

going to try some of those bias options though.