Death by Audio - Fuzz War  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
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Mbas974
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Post by Mbas974 »

Hi everybody, I had the RE of this pedal from our Italian forum.
A smart guy (thanks again!!) tooks some picture and performed a great RE.
Here the details, snapshot and schematic.

PLEASE NOTE that all tranny in the schematic have to be 180° rotated !! (as usual for DeathAudio design)


http://www.sendspace.com/file/ap636b


Enjoy !!

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Post by Suede »

Hi!
In the schematic you posted bubstance there seems to be a DMOS on the 9V supply (VP3203).
Could someone explain its purpose there?Is it used as a voltage regulator?What's the point of a regulator though after a DC supply right? :hmmm:

Is it necessary to include it, because I can't find an equivalent of it.I also can't see it on the PCB photos!

Thanks and since this is my first post here, I have to say I'm very happy to be a member of such a great community!

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Post by bubstance »

Don't worry about it, it's a polarity protection thing I had added out of habit to all of my schems from that time.
powered by 9front

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Post by Suede »

Built one following bubstance's 4-transistor version but needs troubleshooting.
The thing is really,I mean extremely, LOUD.I set my Twin Reverb to 0,5 not even hearing the dry signal and when I turn it on I get heard 2 blocks away!One issue I have is it sounds kind of gatey at times,like a dying battery effect but it goes away sometime,and changes by using the volume control.The sound is definitely in there somewhere though...Any guesses?
I'll try to find a camera and post some pictures later.

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Post by Suede »

Problem solved,the heatshrink on the LED's anode wasn't applied properly so it was touching some solder joints on the board,hence the strange dying battery sounds.

So schematic verified (if it hadn't been previously) ,special thanks bubstance and Glass Hero for your work as well as everyone else involved in tracing the pedal! :D

It sounds as thick and fuzzy as it should.The tonal character of this pedal isn't something special or new to my ears (I'd describe it as a fuzzier,with pronounced high-mids muff) ,but I'm sure it sounds much better than that old weird 5-transistor one.
The tone control isn't as responsive as I'd like, maybe if I build it again I'll tweak the tone-stack.

Like an interstellar overdriver I used to have, it has an insane amount of output, to the point it is almost unusable since it's hard to tame and find a useful setting in a rig.Feels like it'll make your amp explode if set high enough.

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Post by lowbrow »

I've been messing around with this on the breadboard using analog guru's posted schematic for the early seven transistor version. I also breadboarded the later four transistor version, and while it too is also cool, they do not sound the same. Regardless, I corrected the orientation of the transistors, dropped the 27K and pair of germanium transistors on stage 6 and currently have the volume control wired "normally", not as it is drawn (output from C12 to lug 3, lug 2 to output jack, lug 1 to ground). I want to try it with the 680nF caps in place of the 100nF ( I gather some earlier units used the 680nF but ti was later switched to the 104?) as well as bring the volume wired as drawn and hope to tonight.

My point in posting is to mention some things on transistors. I isolated one of the middle stages (Q2, Q4, Q5…take your pick) so that I could test various transistors to see if I could get one of these stages to work without tweaking values. Like many of you I am sure, I have some 2N5088 and 2N5089 trannys from Tayda and tried those first. None of the 2N5089 would work at all. About 2 out of 15 of my 2N5088s did pass a weak signal. At some point I tried some of the "cheap" no name 2N3904s from Radio Shack. These actually work OK and pass a good amount of signal, and worked OK in the stock circuit but didn't blow my doors off. Eventually I tried some MPSA18s I got from Tayda and they worked fantastic! Plenty of output, a fantastic grindy fuzz with some gating in the overall sound but still a decent amount of sustain, especially on chords. I've got some other styles of transistors on order just to try a few different kinds but, frankly, I'm ready to box it up with the MPSA18 transistors. Killer and rather unique fuzz!

I've looked at data sheets and I just don't know what qualities are responsible for the 2N3904s and the MPSA18s working, but not the others I tried...2N5088. 2N5089, 2N4401, 2N2222 plus others. Is it the collector-base capacitance? The emitter-base capacitance? The emitter-base voltage breakdown? Something else entirely? I've seen gut shots from two different seven transistor versions of the Fuzz War but only one specified that 2N5089s where used. I'm wondering if there would be enough difference between, say, a Fairchild 2N5089 and some other brand that one would work and one would not? Did anyone happen to note want brand where used in the pedal or find some that worked in their experimenting?

Lastly, I think the 100K drive trimmer is pretty much useless with the setup as I have it now….20K is much better, but frankly it sounds best (to me) set to zero, so it could also just be eliminated.

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Post by davidstopdroid »

hello, can you repost the schematics file?

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Post by jrfox92 »

Hi, even though this is an extremely old thread, I figured there's no reason to start a new thread. So, I think I might've found an issue with all the schematics/layouts.
After looking at the pictures of the real deal, I noticed that everyone mislabeled the value for one of the capacitors as 680nF when it was actually 4.7nF.
Anyway, I made a Vero layout which I'll try to verify within the next day or two.
Image
and one with just values
Image

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Post by jrfox92 »

Verified. Works as I expected.
I'll post a video in another week or so, after I finish the enclosure and everything.
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Post by Lubdar »

That's awesome!! I'm trying to work on this as well. What brand 2n5089s are you using? I've had some luck with National Semiconductor, but no luck with OEM motorolas. I'm checking out ON Semi later this week, but I was just curious...
Best,
Lubdar

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Post by jrfox92 »

Honestly, I don't even look at brands. If it works, it works. I got mine from Mammoth Elec. so there's probably some particular brand they use, but I don't really worry about it.
As long as the specs are the same, I don't worry about who makes them. :roll:

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Post by Lubdar »

Heh, you're in the same boat as me right now. I've breadboarded this with 2n5089s from mammoth and then tried some that I got from smallbear which didn't work. Its something about the National brand that is different...
Mine are labeled N630 2n5089, i presume yours are labeled the same..

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Post by tabbycat »

jrfox92 wrote:Verified. Works as I expected.
thanks jr and great news. this has had a reputation as a ball breaker for a years. would be nice to think you nailed it.
i hope to have a go this weekend so will report back with a build report as and when.

re the 2n5089, what hfe are you using? i got my harmonic transformer going with 6x 2n5089 @ 900hfe (tried to match closest six in my batch). some have reported that the original transformers used really low (almost off spec) hfe 2n5089 (like 500-600 hfe). am guessing this would suit the higher territory? though my fuzz war has 4x 2n5088 @ 400-450hfe and that stuns.

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Post by jrfox92 »

Now that I'm actually looking at it, I have three different types of 2N5089s in there, too. :hmmm:
Most of them are labeled C 2N5089, one's labeled N624 2N5089 and another is N630 2N5809. They probably have similar specs, but I doubt they act quite the same.
No matter, I don't have any plans to build and distribute these, so I'm not worried about matching transistors.

One thing I'll note, though, is that the schematic (and thus my layout) utilize the Fuzz/Gain control as a trim, so thus you go from a loud and strong, but fairly tame overdrive style fuzz to full on, kinda thin sounding fuzz. So, I'd suggest adjusting the pot value until you find smoother taper, probably something closer to 50K or even 10K.

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Post by Lubdar »

Yeah i'm not planning on distributing my build or anything either, but some other builders were curious.

I'm using 1n34's as the Ge diodes throughout, For the tone stack I'm using 33k/150nF to ground (Assuming that the 120nf and 20nf in parallel of 140nf is close enough...)
and a 3.3nf/33k to ground.

Right now I've got a lot of interaction between the tone control and the volume control, with the volume cranked there is very little difference across the sweep.
But if I turn the volume down to about noon, then there is a tonal shift.

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Post by jrfox92 »

Lubdar wrote:For the tone stack I'm using 33k/150nF to ground (Assuming that the 120nf and 20nf in parallel of 140nf is close enough...)
and a 3.3nf/33k to ground.

Right now I've got a lot of interaction between the tone control and the volume control, with the volume cranked there is very little difference across the sweep.
But if I turn the volume down to about noon, then there is a tonal shift.
I can barely turn the volume up past 10 without potentially blowing my speakers. So, I'm not sure what changes you might've made that could have changed that (assuming that that's part of the issue along with tone control).

As far as the parallel capacitors are concerned, replacing them with one capacitor shouldn't really change much since they're probably getting the same voltage.

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Post by jrfox92 »

The more I mess around with it the more obvious it is that the gain control needs to be changed to a better value. Right now it's basically just a switch where 80% of the taper is a loud as all hell clean-ish tone then it's just full splatty, treble heavy, incredibly insane fuzz.
But, I don't even think they use the 7 transistor version anymore.




















Probably because it sounds kinda shitty. :slap:
But I digress.

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Post by Lubdar »

Yeah I don't have the gain control on mine breadboard setup, I wonder if a smaller value pot tied from 390ohm to ground would work better.
I was going to try out using a 1M pot on the input (like the megalith) to be a sort of saturation control. Since the Megalith(aside from the boost control) is essentially an aweomse full on Fuzz with the only taming elements being the input and output potentiometers.

The reverse sound is pretty awesome, but I'm testing out some other transistors to see if this circuit will play well with others :) Otherwise I'm sure stacking some of Jack Orman's Reverse Boosters http://www.muzique.com/lab/reverse.htm cascaded might get something similar with a bit more stability, I have yet to try it though...
Best, Lubdar

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Post by Lubdar »

I ordered a batch of 2n5089s from Mammoth this week, 8 of them were C 2N5089, and 2 were National Semiconductors. So far I've tested the national, On Semi, and now these C brand 2n5089s. In order of descending performance, the Nationals work the best, then the C, then the On Semi...

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Post by jrfox92 »

That's an interesting tidbit. Perhaps I'll look into matching the transistors for the next build. The current one was mainly just an attempt to help grow a friend's pedal collection, but I think I'll try finding some better components for the future.

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