freestompboxes.org

Well, thanks to jerms over at the DAM forum, I finally got to trace the Two Face. I'll tell you right now.... not for the faint of heart. The amount of el cheapo wire that's stuffed into the enclosure is hallucinatory. Take a look.....



I also had a request for a close up of the knobs, so here are some more shots, including the fuzz, and clean board. The 12vac to +/-12vdc board is identical to the PLL, or Lion.















And of course, my trace,





Going to breadboard this in the coming weeks to validate the trace. I've been playing with this over the past few days, and it's a little reminiscent of the Skyripper, but more menacing. It's noisy, buzzy, with lots of Velcro stuff going on. Has settings for oscillation induced screaming, and much of it is interactive with the guitar's volume. Just a plain weird-ass box.

I love it.

I'll will try (I mean try) to put together a video of this unit in action. I'm not really happy with the videos out there now, since they don't show the guitar volume interactivity, which is important. It just so retarded though, I don't know where I'll start.

EDIT: I've added the power pin numbers to the LF351 in the schematic. I forgot before, sorry.

Sorry, here is the new schematic, with the power pins numbered.

Thank you for another contribution. Great job as always

It's good to know that someone's wiring and soldering skills are worst than my little son

Designwise - I will look at it when I get myself together after that shock

I usually try hard to restrain myself from commenting other folks build quality and methods, but dude. What the f....!?
+m

There was an error with a cap on the clean circuit. Here is the corrected version.

mirosol wrote:I usually try hard to restrain myself from commenting other folks build quality and methods, but dude. What the f....!?
+m

can't find your soldering iron? fuck it, use the cake icing thing instead.
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Here's my vero take;



It'll fit nicely into a 1590J.

Here's the updated schematic, and switching diagrams as well;

what a mess, which makes this layout even more impressive. great work! i'm a bit thrown off though with what's going on with the trimpots used. is one of the outer lugs on the trim pot(s) tweezed off, with a jumper going from the wiper to where that tweezed lug would’ve gone at the bus below, without any real trace cutting to the vero itself?

also, are C4, C14, and C15 bi/non-polarized electrolytics?

I'm also counting 71 trace cuts in all if those are cut traces underneath the trimpot's (68 without). was the 70 cuts originally listed on the layout a mistake with an extra unaccounted for trace somewhere on the board? I guess this would in turn help answer a part of my original question with the trimpots too.

thanks alot!

just listened to a couple of demos of this on yt

and it sounds how i imagine a fuzz factory made out of vacuum cleaner parts would sound. or a stylophone being played underwater. it clearly does every conceivable flavour of gatey and starved, but is there much gutsy fuzz potential in there too?

BakedAlaskan wrote:what a mess, which makes this layout even more impressive. great work! i'm a bit thrown off though with what's going on with the trimpots used. is one of the outer lugs on the trim pot(s) tweezed off, with a jumper going from the wiper to where that tweezed lug would’ve gone at the bus below, without any real trace cutting to the vero itself?

There is a cut on the vero where the third leg is located, and then you bend the third leg over, and solder it to the second leg. Just ensure that the third leg doesn't contact the trace that's been cut in any way.

BakedAlaskan wrote:also, are C4, C14, and C15 bi/non-polarized electrolytics?

Yes.

BakedAlaskan wrote:I'm also counting 71 trace cuts in all if those are cut traces underneath the trimpot's (68 without). was the 70 cuts originally listed on the layout a mistake with an extra unaccounted for trace somewhere on the board? I guess this would in turn help answer a part of my original question with the trimpots too.

Recount confirms 71 cuts, and not 70. My apologies. I'll make the necessary corrections.

For those of you that are a bit more adventurous, here is the vero that I'm working on now. This one includes diode choice selection for the input to each fuzz. I've tried germanium diode (1N270), and it does provide different flavors of Velcro. You can try different diodes, ymmv.

tabbycat wrote:just listened to a couple of demos of this on yt
and it sounds how i imagine a fuzz factory made out of vacuum cleaner parts would sound. or a stylophone being played underwater. it clearly does every conceivable flavour of gatey and starved, but is there much gutsy fuzz potential in there too?

The gutsy fuzz appears in LINKED mode, when both are working together. That's why I'm sort of hyped on this project. When linked, you can dial in a really good fuzz, without all the noise effects. It really does remind me a lot of the Skyripper, sound-wise.

I've tested 2N404/2N1304, and GT402/GT404 combos, and both yielded very good results. The Russian transistors are noisier on the breadboard, but that might disappear once enclosed. As for gains, 2N404/2N1304 combo I'm using are 75/95 for the PNP side, and 125/190 for the NPN side. For now, I've installed sockets on the board, and I'll be testing different combos until I'm satisfied with them, then I'll solder them in.

In the end, as with any Ge fuzz circuit, it really does come down to transistor selection. The original used NTE102/103's, and from what I've encountered, my version sounds much better. By "better", I mean, the controls are much more responsive, and the fuzz sounds meatier than the original, or any of the YT versions, for that matter. Either the NTE's that Schumann was using were crap, didn't bother checking gains, or all of the above. From my explorations of three different PLL units, it looks to me that Schumann was a creature of opportunity, and tended to use whatever he had close at hand, or easy (cheap?) access to. Of course, that just makes it more interesting for us... right?

unbelievable work! great demo by the way, sounds like a nightmare in the best possible way!

did you end up using a c100K dual gang for the drive control and an A15K for the sense controls? I'm having real trouble finding either of those values anywhere for sale, then again its gonna be a long while till I tackle this and should have plenty of time to keep my eyes open for them.

BakedAlaskan wrote:unbelievable work! great demo by the way, sounds like a nightmare in the best possible way!

did you end up using a c100K dual gang for the drive control and an A15K for the sense controls? I'm having real trouble finding either of those values anywhere for sale, then again its gonna be a long while till I tackle this and should have plenty of time to keep my eyes open for them.

I really wanted more control from the drive, so I separated them. They're still C100K pots. You're correct on the limited availability of 15K pots, so I went with the more available A20K. Works fine.

Here's some pics of my build. I housed it in a 1590J;





The four russian transistors look like silos, full of crazy fuzzy goodness.



Controls are basically the same, except I seperated the Drive pots, and added germanium doide selection for the clamping.





I had a choice of three different combos; AC128/AC176, 2N404/2N1306, and the GT402/GT404. Specifically, I'm using GT404G, and GT402V here. They both have an hFe range of 60-150, and I selected transistors with leakage below 300uA. One transistor is around 275uA, while all the rest are below 150uA. Q1/Q3 come in at the 80-85 range, while Q2/Q4 sit around 112-115. As you see, it's Fuzz Face range, and the closer you can mirror them the better.
Why did I go with the Russian transistors? Because;
a) I have lots of them.
b) I like the look of them.
c) The leakages are fairly low, and matching up pairs was fairly easy.
d) Cost is low.
e) I have lots of them, and I like the look of them, and they're cheap.

Voltages are as follows (Q1/Q2 are the NPN, Q3/Q4 are the PNP);
NOTE: Sensitivity control at noon, all others at zero. Oscillation controls off (at 1 on my unit's rotary switch, 2 using the originals on-on-on switching), nothing plugged into input or output.
Main voltages = +10.94, and -10.49

Q1
E = 0.0v
B = 44.2mV
C = 1.418v

Q2
E = 1.280v
B = 1.418V
C = 1.296v

Q3
E = 0.0v
B = -40.8mV
C = -1.458v

Q4
E = -1.270v
B = -1.458V
C = -1.289v

For the most part, rail voltage-wise, you can run it anywhere between 7 to 12 volts, but you have to compromise at some point. Too low a voltage will starve the crazy oscillation side of things, and too high will render the normal fuzz almost useless. Keep in mind, all this depends on the transistors as well. Lots of variables to consider. This one has been on the bench longer than any project that I've ever done. The madness would get to a point that I would get tone deaf, and have to walk away from it for a day or two. Come back, try different things, walk away, and so on. The half volt offset on the rails is there to balance the transistor voltages as much as possible. The only other place where you could mess around with is the voltage divider at the input of the fuzz opamps. You could tweak the voltages here, to balance the input voltages between the two, once the transistors are evened out, but this is really nit-picking.

The other changes I made was using TL071's instead of LF351's, polystyrene caps for the diode clamping, and as I mentioned before, added 1N270 diodes for added craziness. An 680pF cap replace the 33pF, and an 1800pF instead of a 47pF cap. I found that upping the values stabilized some of the oscillation settings. You can experiment with different values here. I just didn't like the LF351's either. The drive seems to be much more stable with the TL071's. Oh, and R9 I changed from 330K, to 240K, to up the voltage at the opamp input. I found the input signal a bit weaker on the NPN side, so it increases the voltage another .5v. This gives me a 1v difference between the two sides, but evens out the output. The optional germanium diode add-ons are 1N270's.

As for the fuzz, at it's mildest, it's like the love child of a pissed off Big Muff, with an Uglyface, and a Skyripper being the crazy uncle. Very hard squarewave. From there, velcro, mosquito, octave jumping, motorboating, oscillation of every audible frequency, and then some. It's a knob twiddlers dream. Linking the two circuits, you can affect one side using the oscillation from the other. Craziness! The seperate drive pots really add to the attainable textures, and the lower Vf of the germanium doides can push the oscillation to different levels. Totally interactive with the guitar's volume, and tone knobs as well. With the right settings on the unit, you can have oscillation on demand using the guitar's controls. My fav setting right now is one where a short burst of oscillation can be initiated by pick attack. I hit a chord or note hard, and a short blast of oscillation cuts in, followed by the chord or note. Less pick attack gives you the normal chord or note. Too cool. :icon_cool: Mixing in clean signal just adds more texture to the whole shootin' match. And then, just when you're blowing ear drums, you can kick in the boost, and melt some brain cells as well.

Here's the video. A word of warning; it's fairly long, and there's a lot of talking. It's quite the tweak monster, and I try my best to demo it's capabilities, while explaining what's going on. Be ready to fast forward if boredom sets in. There, you've been warned, so I don't want to hear any bitching.