FetZog (Request)

[Silver Blues]

I didn't know what the transformer was supposed to be, so I assumed it was one of the 42TMXXX series ones without the center taps connected, so I ran with that. Also, I apologize about the slanted resistor there by the transformer, the layout was already large and I didn't want to add two columns and make it even bigger.

[Sergio]

Thanks a lot, Silver!) These days are full of family events, but on a pair of days I ll go with that and a tychobrahe transformer style... I ll be posting here how that works!
 Cheers,
   Sergio

[johnk]

just and FYI, there's actually 15 cuts on siilverblue's vero.  the lower bare board is missing the two under the 220K resistor.

I also drew up a vero using silverblues' layout but was able to make it a bit smaller #21 x 12# so it would fit in a 1590B#

[Silver Blues]

Ah yeah, thanks for catching that  I hadn't thought of what you did with the 6 ohm, that's clever actually. Thanks for the review John.

[Sergio]

A big thank you, John and Silver! Tomorrow I ll be able to build the thing up.) I ll tell you how it woks.
 Cheers
  Sergio

[Silver Blues]

Shit, I missed something else. There should be a cut separating the wipers of the two bias trimpots.
That's what I get when I don't review carefully enough  a cut at position GB on my layout will do it.

[johnk]

I just added the cut on mine so as long as everything else is correct, it shoud be good to go

[Sergio]

I built the circuit tonight, but no success! At least, until the moment, Ive changed transformer orientation and nothing,
I biased 2nd transistor at 4.5 but 1st transistor couldnt manage to make it less than 5,8-6volts, i dont know if that can be the mistake, or a wrong transformer. I readed something about an Octavia similar transformer, I can try with a brassmaster one too..
 I ll keep telling you about the progress, i hope!
 Thank you,
  Cheers,
  Sergio

[johnk]

I think that with either layout you should be able to bias Q1 and Q2 at just about any voltage that you want. first i'd check for a shorted row, cut or a misplaced or bad component around Q1.

[Mark SL]

Built JohnK's layout and its not working.   Any thoughts?

[johnk]

I just checked my vero against the posted schematic of it again and there are no errors that I can find. I haven't built one yet but if the schematic is correct, the vero should be too.

[Sergio]

I requested this one, built this, but havent managed to get sound out of it, still Im trying to debug, but the web where I dound the schematic had no information about schematic being verified. Maybe it's wrong in some place.

[Mark SL]

Its definitely different from the original schematic.  What schematic was used?  Can you post that one?

[johnk]

from diystompboxes:
http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/FetZog/FetzogSchemDIYSTOMP.jpg

[Mark SL]

It looks like the last j201 is backwards.

[johnk]

nope. it's not backwards but I think the that the last 22uf's positive should've been connected to the source and not the drain.. I corrected it now.

[glasspak73]

Has anyone verified this yet?

[glasspak73]

I want to build this asap but i dont have a clue what transformer to buy?can anyone help?I will build it and post all my results.I also have a 1987-92 fender champ 12 that i want to try converting into a real herzog,Is there anyone on here that can help me with a few questions i have?

[Silver Blues]

It wasn't listed on the original schematic, but I assumed it was a 42TMXXX like that in an Octavia. Give that a try. Also I believe John's layout may be more correct than mine so go ahead and build his.

[glasspak73]

I have found the 4TM022 transformer on mouser.what is the purpose of this transformer in this circuit?sorry if this is a stupid question but this will be my first circuit useing a transformer on the output.just trying to get a better idea of what it does and what other may be a good substitute.