Flipping a PNP circuit

S

stinkfeet

New member
Hi everyone! I'm working on my trace of the 3 GE transistor fuzzrite, and I wanted to not have to add an LT1044 and instead just flip the circuit so it'll interface nicely with other pedals. I learned about this technique from Union Tube and Transistor's tour bender. I wanted to confirm that I should send C4 to the positive rail and leave R9 grounded, right?

Here's the trace
3 ge pnp fuzzrite reissue.png
Here's the flipped one
flipped 3 ge pnp Fuzzrite-reissue.png
Here's what I based it on
unionT&T tour bender.PNG
 
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You could try the GE 2N169. I believe Amplified Parts still has a ton.

Fantastic NPN Germaniums. Raw stock usually in the 60-100 hFE range with low leakage.
 
Ginsly said:
Ah, so you're aware of the Pyrite! :)

Did you trace an actual unit?
Click to expand...
I was looking for the 3-transistor variant after hearing a certain YouTuber's demo, and I stumbled across the Pyrite. It's really cool! I'm glad I'm not the first person interested in this fuzz.

I'm grateful for the photos you posted on this thread because that's what I used to trace it, as I couldn't find any other info on this pedal other than that one video. This is my first pedal trace, but I have traced quite a few tube amps. I think the trace is right, but with the limited pictures and messy wiring, it's hard to tell. R1 should come after C9, and I couldn't 100% make out the multiplier band on R1 and R2. R12 is probably a 22k, not a 47k.
 
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Big Monk said:
You could try the GE 2N169. I believe Amplified Parts still has a ton.

Fantastic NPN Germaniums. Raw stock usually in the 60-100 hFE range with low leakage.
Click to expand...
NPN is probably the best way to go, but I have some Russian MP42Bs and MP25Bs coming for a harmonic percolator, and I was planning on using the low hfe ones for this since this circuit is designed for 20-40 hFE transistors.
 
Ha, those pics! Well how bout that.

The general flow of what you have here is what I originally thought Sanner had done - simply plop a gain stage in front of a standard Ge Fuzzrite and call it a day. And it does indeed sound like a supercharged Fuzzrite should when doing it that way! I'm not even sure which way I prefer... That being said, I really wanted to hew as closely to Sanner's pedal as I could when making the Pyrite.

If you look at the annotated pics - you have Q1 labeled correctly. But - look at that 47n coming from "8" on Q1 - where does it lead? It connects to "2", meaning that the transistor you've labeled Q3 is actually Q2. This transistor has the 22k/47n-to-ground/100k situation, which I found to be odd - Sanner flip flopped what was originally Q1 and Q2, swapped some resistors and then added a boost in front - at least that's what it looks like to me.

I'll follow up later with some value differences I found (some of yours must be guesses), but take another look at the flow of the board and see if I'm crazy or not! :)
 
Ginsly said:
Ha, those pics! Well how bout that.

The general flow of what you have here is what I originally thought Sanner had done - simply plop a gain stage in front of a standard Ge Fuzzrite and call it a day. And it does indeed sound like a supercharged Fuzzrite should when doing it that way! I'm not even sure which way I prefer... That being said, I really wanted to hew as closely to Sanner's pedal as I could when making the Pyrite.

If you look at the annotated pics - you have Q1 labeled correctly. But - look at that 47n coming from "8" on Q1 - where does it lead? It connects to "2", meaning that the transistor you've labeled Q3 is actually Q2. This transistor has the 22k/47n-to-ground/100k situation, which I found to be odd - Sanner flip flopped what was originally Q1 and Q2, swapped some resistors and then added a boost in front - at least that's what it looks like to me.

I'll follow up later with some value differences I found (some of yours must be guesses), but take another look at the flow of the board and see if I'm crazy or not! :)
Click to expand...
Okay, I definitely got Q2 and Q3 swapped on the annotation, and now that I look at it again, I got the collector resistors flipped from Q2 to Q3. I must've been thinking that the one with 22k/47n-to-ground/100k22k/47n-to-ground/100k had to be v3.

Thanks for checking my work!

Here's the proper one
fuzzrite-3-ge-pnp-trace_v2.png
 
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