Roger Mayer Classic Fuzz vero question

[vizcities]

So: I am not a breadboarder, nor am I vero plotter - at this point, I'm basically a guy who neurotically checks his solder joints and follows directions well, so my circuit reading skills are non-existent.  (I teach, so I'm waiting for the summer to arrive so I can build them up.)  At the moment, I'm building my brother a Roger Mayer Classic Fuzz, which is (as I'm sure many of you know) just a modified PNP Fuzz Face.  Some of this seems pretty easy; swapping out resistor, cap, and pot values shouldn't be a problem.  However, the Classic Fuzz has an extra .0022uF cap connected to the Volume pot (47k on the Classic Fuzz, 500k on the Fuzz Face) and I don't know what to do with it.  Can anyone tell me where to place it on the attached vero layout?  Or is it something I need to solder onto the pot itself?  Also: AC128s are crazy expensive.  Is there a more available (and cheap) alternative?  And do I need to get matched transistors?

Fuzz Face schematic:


Fuzz Face vero:


Classic Fuzz schematic:

[vizcities]

OK, based on the Fuzz Face vero posted earlier, I think I can insert the Classic Fuzz's extra cap if I:

a) Extend the veroboard to 10 horizontal spaces.

b) Put a trace cut at b8.

c) Put a .0022uF non-polarized cap at b9 & c9.

d) Wire Volume 2 at b10, Volume 3 at c10, and Volume 1's lug to ground.  (Not sure if positive ground or negative ground - I've never built a PNP pedal before.)

Does all of this square?  Pardon me if I sound like an idiot - this is my first schematic reading session and I'm pretty confused.

[TGP39]

Hi Vizcities. The Roger Mayer Classic fuzz is a positive ground effect in its true form. There are ways of changing this to a negative ground effect, but the vero and schematic you showed are for the positive ground effect. This isn't a big deal if you use a battery to supply the voltage to the circuit.
     To answer your other question, from the schematic it looks like a 2.2nf non-polar capacitor has one leg connected to lug #2 of the volume pot and the other leg connected to lug #1 of the volume pot. I would think directly soldering the cap to the volume pot would be much easier than changing the vero layout.  Notice how lug #3 of the volume pot is directly connected to ground so the more you turn the volume pot clockwise, more voltage is sent to the output = greater volume.
     The AC128's are expensive, but they do sound really nice in this circuit.  You could try other PNP transistors (Hfe of around 80-110 I believe) and see how you like the sound.

     Hope this helps.

Steve.

[TGP39]

Forgot to add a great read about fuzz face designs....
http://www.geofex.com/article_folders/fuzzface/fffram.htm

Steve.

[vizcities]

Awesome!  This is just the kind of info I needed.  Like I said, I'm pretty good at following instructions, soldering correctly, and even troubleshooting shorts and stuff - I'm just a rank amateur at reading/enacting schematics.  (Btw, the Fuzz Face page is good reading; thanks for the suggestion.)

[Bret608]

I think you should take this layout as your jumping-off point: http://tagboardeffects.blogspot.com/2010/02/roger-mayer-classic-fuzz.html. It's for tagboard and not vero, but I think when you look closely you'll see there are mistakes on the schematic you're using (e.g. the volume pot isn't shown; what appears to be a volume pot is actually intended for bias).

Then, you could just look at a standard vero PNP Fuzz Face layout on this same website (tagboardeffects.com) and walk the parts values across pretty easily. You'll find it hidden in a post entitled "A few veros..."; just use the site map to find it. Mike's layout looks good, but it's going to be hard to walk across to this Mayer schematic given that it's not quite 100% usable as is.

[vizcities]

That List of Veros page actually seems very useful for the future - I've been meaning to play with the Fuzz Face circuit in general and it seems like a great place to start.  As far as the Classic Fuzz and its messy schematic go, I managed to find an all-purpose PCB at GuitarPCB that should simplify this quixotic quest for me:

http://www.guitarpcb.com/apps/webstore/products/show/1514021

Hopefully this will make the build quicker/easier.  Quick Q, though: where would one go to find decent (i.e. GeoFex's 80-110 gain prefs) AC128s?  I've seen a few on eBay, but they were neither cheap nor necessarily reliable.  Or is this a question I should relegate to the Parts Jar forum?

[Bret608]

I would check out DIY Guitar Pedals, which is run by Chromesphere here on the forum. He sells measured and tested AC125 sets, which will not sound any different than the AC128s. Really gain and leakage is more important than the part number.