The Planet Smasher - Ge transistor overdrive from capt. Brannigan

[Zapp Brannigan]

Howdy folks! What do you think about pocket-size black hole generator from ye olde buck Zapp? If you don't mind I'll share the secret of this deadly weapon with you. Let's suppose you said: "OK!"

The schematics is rather simple and  reminds Big Muff a bit. So here are the recommendations that might be helpful:
http://www.kitrae.net/music/big_muff_guts.html

Some comments about my scheme:
1. I found it in old russian book on semiconductor electronics, it was published in 1979-1981. So the conclusion is that the schemo is for low-impedance pick-ups (this type pickups were most widespread in Soviet Union. Actually they were the only type of pups during the period). Quite dissappoiting, right? NOPE,GUYS - it sounds awesome with single-coil pups.
2. I also modified it - original scheme contained some kind of noise gate. I threw it away - who needs noise gates? But not only that - input cap value is reduced, gain pot is inserted between cascades 1 and 2.
3. Possible mods:
- Another tonestack. Original TS is crappy and must be eliminated. That is tha law of Brannigan.
- Rotary switch with a battery of caps instead one input cap
- Kick away gain pot! Swap R11 trimmer with a normal pot and enjoy (at least I think gain control might have become more adequate)
- Place source follower in the input (you'll need p-channel Jfet). Why, would you ask me? Remind what I said before - the thing sounds good with single-coil equipped Strat, but not good with humbuckers because of low input impedance. Source follower will solve the problem
3. Transistors: I used old russian MPs 28 and 42, but you may replace it with any other Ge transistor which you prefer, for example in Fuzz Face.

So, meet the schemo dudes!

http://ge.tt/7DYebUt/v/0?c

[Jaicen_solo]

AVG tells me your site is infected with a Virus.

[psychedelicfish]

Schematic image:

[Zapp Brannigan]

Damn, it was fine recently. Wait a minute, I'll try to attach the scheme in another way.

Thats it:

https://hotfile.com/dl/248666826/5ebfb0f/no-ng.pdf.html

psychedelicfish, thank you, dude!

[mistahead]

Who wants to teach me what the correct term for the below statement (RE this design) would be?

I like the way (appears via schematic) the feedback network seems to be layed out to push back through the amplification Q's, rather than the Q's pushing forward and the feedback network venting that push back around.

Who can f-n interpret that... hmmm.

[mac]

Interesting. I'll give it a try.

Q1,2 seems to bias near a volt or so for a wide range of leakage, same for Q3 which should bias near Vcc.
Q1 might need some fine if you put a very leaky germ there.

R23 and R21 are not decoupled so they might crackle a bit like the Rangemaster pot.
Is the schematic right?

Some input and interestage series resistance can help to avoid HM and stages loading.

mac

[Zapp Brannigan]

R23 and R21 are not decoupled so they might crackle a bit like the Rangemaster pot.
Is the schematic right?

There is a description of mods I made in the first post. R23 in original scheme situated before input cap as a rheostat, I placed it between cascades 1 and 2. R21 was untouched by my dirty hands. The device is built, tested and now lives in my pedalboard. Both pots work fine without crackling.