tres hombres

[rocket88]

Just saw this posted by mac on DIYSB forum. Here's what he said about it:

"Do you have some unused low gain, med leakage germs?
Here is a classic 3 stages circuit I built this weekend using some unused 2SA101 Matsush*ta PNP Ge about (50; 150ua)
It also works with Ge as low as 20-30; you can try lower inter-stage resistors.
It can easily be adapted for low gain silicons like TIPxx, BDxxx, MPSA92, etc. Just replace those 22k with 33k.
D1 can be omitted, I did not use it."



Thought it might be good since, I know a lot of us are collected Ge Transistors and can get a lot in the lower hfe range. Not sure how it sounds though.

[johnk]

the schematic that you posted is an unreadable .gif file.
what's the link to the thread?

[johnk]

nevermind. I found it. I also drew up a vero for it, but it's not verified yet.

[rocket88]

Shit. I'm sorry. I didn't realize it was unreadable once it was uploaded. I wonder what this thing sounds like and it its any good.

[johnk]

I have no idea of how it sounds. IMO, building home-made circuits like that one are pretty risky.

if you want to build it to find out, i'll post the vero for it.

[Geezer]

John, please post the vero....I'd like to give it a shot

Jeff

[johnk]

[iggy]

so how did the pedal come out? love that old ZZ top sound. did it work?

[rocket88]

I haven't had a chance to build it yet, been too busy with work. It's in my queue. Give it a shot if you can, I don't know when the next time I'll get enough time to build.

[iggy]

Can you tell me where to find the original information you were basing this off of? I tried to find it on that forum but didn't have any luck. I'd like to see what its about before investing the time.

[johnk]

it was on the diystompboxes forum. here's the posted schematic:

[iggy]

i'll give it a shot. if you think it'll work.

[rocket88]

go for it iggy, and let us know how it goes. i'm pretty sure it should work.

[iggy]

i'll breadboard it this weekend. if the circuit works i'll build the board. I'll post here after seeing what happens.

[iggy]

Well i built the circuit and it does work. I need to play around with it some more. It sounds like a low grain overdrive to my ears. Might have some potential. Ill try some different trannys and work on the biasing. to see what it'll do. I'll post more feedback when i get a chance to play with it some. more.

One question should all the tranny's bias in the same voltages? t2 was way off from the other two. maybe 1.5-1.8 volts instead of 4-5 volts. from what i remember.

[johnk]

from the looks of it, to me, all of the transistors should be biased the same.
i'd first try swapping them around to see if the low voltage follows the tranny or the circuit.

[rocket88]

glad to hear the circuit works. once iggy get's done playing with it, hopefully it will be something really worth building.