anyne built one with success??
It says PNP version so I expect that I connect the power like a Fuzz face with the -9v to the board instead of the +9v?? It says =(v at the top where the power connects but I can't seem to get it working.

any help is appreciated and pic of the build would be even better  :wink:

Thanks
Mike N.

OK, it's spitting and sputtering a little now and I have to hit the strings really hard to get just a little sound.
Do I need to bias the trannies?? isn't that the reason circuits like this don't work well or spit and sputter??

 Which trannies do I have to change or could I use some trim pots for certain ones?? My meter is broken so I can't take any readings and I can't afford a new one so any guess work would be appreciated.

Mike N.

I built it. I followed the schematic without make any changes. I used 2N3906s for the PNPs and 2N4400s for the NPNs and worked at the first try.

suggested that matching closely the two 68k and two 22k as well as the two diodes with a multimeter...the target zone for these values being small [that they are very close to same value as the 'other one'] is stated as being necessary to get a 'full wave' ? rectification or best octave.

Quote from: Mike Nichting... I have to hit the strings really hard to get just a little sound...

Mike, my guess is the diodes didn't get flipped around and aren't biased ...  - diodes should be Germanium ...

there are no diodes in the layout~!! I'm not talking about the Original green ringer of which I've built 2 that work beautifully.
This is the 21st century layout by Hemmo.
It consists of 4 trannies(2-3904/2-3906) a couple of caps and a few resistors and 2 switches. One for fuzz and one for clean octave.
Do I need to add diodes and if so where??

I will send this schematic to you JCM if you want to look it over and give me your opinion.

Marcos, do you have a pic of your build??

Thanks all,
Mike Nichting
BTW- JCM, I never did get the "NULL" mod working on my regular GR's ??!!  I'm not sure what I did wrong but I followed your instructions to a "T". BTW- you rock bro~!!

Sorry, I don't have a pic.

Finally dug up the old Electronotes sheet on using equal-value-R single-transistor rectifiers.

Bernie Hutchins notes that the value of the Re should be about 8-20% smaller than Rc for optimum functionng, depending on the specific transistor involved.  Of course, he illustrates this with an NPN where the collector goes to V+.  I'm not enough of a transisto-phile to know if this means the resistor to ground (from the collector of the PNP) needs to be tinkered with here, or whether it is the Re, regardless of connection or orientation.

I suppose the safest thing to do is replace the 10k Rc resistor to ground with an 8k2 resistor and a 5k trimpot, so that it can go from a bit less than 10k to a bit more, and tinker until it sounds best.

thanks Mark~!! But ........um.....could you tell me which one that is??
Do I add the 8K2 and 5K trim in series where the 10K was?? Is that what you are saying?? There are 3 10K R's going to a transistor in this layout.

I'm dumb and not ashamed to admit it. Please tell me more so that I can get this thing working. I can hear a slight bit of ringer when I strike the strings and it's just teasing me.

Thanks again Mark.
Mike N

The second transistor is a PNP, right?  In many other octave-up units that use this single-tranny FWR trick, like the Fender Blender, Superfuzz, Tone Machine, and Scrambler, there are equal-value resistors from E to ground and C to V+.  In this case, using a PNP means the resistors go from E to V+ and C to ground.  What I am suggesting is that maybe the place to stick the trimpot is between the collector of Q2 and the resistor to ground.

I too am not ashamed to admit I don't know much about these things, so I don't know if this is the right one to tinker with or whether it is supposed to be the other one (E to V+).  That's why I suggest that resistance be variable from less than to more than 10k.

Thanks Mark~!!

 I guess it wouldn't hurt to make all of them trimmers would it?? That way you could dial in anything you need and then go to permanent resistors??
I know this isn't a new idea but I huess it would work??
I finally fixed my meter so I can check some voltages hehehehehe  

 Thanks for the help sir it is much appreciated as always~!!!

Mike N.