Pro Analog MKIII Fuzz

[acdsee]

Hi i'm searching for a schematic or some info about this fuzz but can't find anything.I think it is one of the best benders out there so it's worth some time to trace it.Could anyone who owns the pedal help?

[casiotone1331]

Im a friend of Scotty's.

He says "good luck".

[IvIark]

That's awesome, thanks very much, and thank Scott from us too

[acdsee]

Thank you very much, its been along time searching for this one!

[Neil mcNasty]

Here you go:

[Sphere80]

 Verified.   I had trouble with the layout on the main page oscillating, but this one works.  I only flipped #1 & #3 on the fuzz pot.
   Acdsee has also verified it and recommends a matched TBmk2 (not mk3, of course) set. Due to the filtering, it's pretty mid focused and high gain.  There are 4 and 5 knob "Plus" models, but I think they attenuate the hot signal or help get a gated sound. This sounds excellent as is.

[Frank_NH]

I looked over the main page vero and the only difference I see is in the position of the 100uF cap.  I believe the main page's negative end of the electro should connected to the top row so the 100 ohm + 100uF cap form a proper filter.

I just got some Ge PNP transistors and will try out this circuit myself.  One thing I believe will help with oscillation is to make the power filter cap bigger (> 100uF).  I have a bunch of of larger caps and will try those.  It may also be helpful to put 100nF ceramics in parallel with the large electro for additional filtering.

It would be cool to add a charge pump to provide the -9V supply.  That may also help with the oscillation as you could put all your power filtering there.

[Sphere80]

Thanks, Frank_NH, that did it!  Noise is gone. The layout on the main page just needs that correction, and the rows corrected to 16x10.  http://tagboardeffects.blogspot.com/2016/02/pro-analog-mkiii-fuzz.html

[Frank_NH]

Excellent!  The nice thing about these circuits is that there aren't a lot of parts so it's easy to put a larger filter cap in there.  I have some 220uF and I think a monster 470uF too.  For noise suppression, nothing beats these large caps - but their size can be an impediment.

BTW, for charge pump circuits, tantalum caps are supposed to be best due to their low esr.  More info at the link below.  Make sure their rated at greater than 2x the supply voltage and don't ever hook them up with reverse polarity!

https://forums.qrz.com/index.php?threads/tantalum-instead-of-electrolytic-capacitors.566140/

[Sphere80]

Thanks for the charge pump advice.  Where would you place it? Would you remove not only the 100uf but is the 100R unnecessary now?

  Taking advice from board member Anders,  I converted mine to NPN by flipping the electros and using  MP38A, MP38A and a leaky GT404B  for Q3.  He pointed out that this is obviously a Rangemaster into a Fuzz Face.