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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Glass_Hero
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my favorite amplifier: My Glass Hero Amplification
Completed builds: 1973 Orange Graphic 120 head
Fender Champ clone head
custom Pentode input single channel 20 watt head
custom "plexi" 5 watt single ended head
custom Pentode input single channel ~2 watt combo (smaller version of my 20watt)
( i build amps and pedals )

pedal clones
Pro Co Rat
Univox SuperFuzz
Sonic Edge J&J Overdrive
Interfax Harmonic Percolator
EHX Electric Mistress
EHX Big Muff PI
EHX Big Muff into a DBA Fuzz War
Green Ringer
Orange Squeeze
Boss Slow Gear
Death By Audio Sound SAW
Death By Audio Armageddon
Death By Audio Fuzz War
MXR Phase 90
EA Tremolo
TS 808
another TS808 modded out for bass
various loop, boost, kill, stutter, feedback and signal pad stompboxes

pedal modds
big muff clipping modds and internal feedback loops w/ LDRs
EHX POG exp pedal modd
VOX 847 wah modds (expression pedals should be expressive)
Cry Baby Modds
BOSS XT-2 modds


this list is tragically outdated..
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Post by Glass_Hero »

bubstance wrote:If anyone with a 4 transistor Fuzz War could check something, I'd be very grateful. There's a mystery resistor tied to a 100R and one lug of the trimmer... in the pictures provided by headless I can see 3 of the bands (the last three; black, red, gold) but the first band is completely obscured by the battery leads. I'd guess it's either 1K or 2K, but any info would be much appreciated.
i think they wired the trimpot similar to the sustain control on a big muff.. i have not finished tracing it out yet.. because the guitar shop i work at just got an apocalypse pedal in and instead of tracing this i decided to remove portions of my hearing range..

so i can either post pics of the apocalypse or trace this circuit.. i have a busy weekend and i can only do one or the other..
culturejam wrote:So I just googled "reverse beta" to see if I could do some reading on the topic. First search result:
http://www.muzique.com/lab/reverse.htm
However, the most interesting effect is when this reverse booster circuit is driven into clipping - it clips in a matter totally unlike that of the basic common emitter circuit! The overdriven reverse booster generates a mess of harmonics different from other clipping circuits and configurations.
i was looking for this yesterday and was going to post it.. and yeah i'm pretty sure DBA was trying to be different and stuck the transistors in backwards.. I read somewhere the guy did some 'circuit bending' awhile back..but since i have friends that are into 'circuit bending' i'm going to avoid that whole topic.. I do however think they have come a long way from their beginnings.. and yeah they do need to use more solder on their builds.. some of the traces are way to thin, while others are way to thick..but i would assume they are still just 'fucking around' with a pcb layout program..the underside of the apocalypse doesnt appear to have too many of the thin/thick traces.. and since that is the newest release i would hope they stick with cleaner layouts..
ShortScaleMike wrote:Well consider me schooled! My frustration with this pedal came from building one and struggling manfully to get anything decent out of it without extensive changes. Maybe I missed something stupid.

I appreciate all your responses and the tech insight.

I'm not a fan of the Tubescreamer though, so count me out there.
did you have the transistors in reversed? collector to ground, emitters to the positive voltage? if you had it bread-boarded and tore it apart, wait unitl we come up with the 4 transistor model it looks like a better circuit..

sorry about the tube screamer comments..i hate tube screamers, its probably the most overrated, over-cloned, over-discussed pedal on the market..

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Post by culturejam »

Glass_Hero wrote: I do however think they have come a long way from their beginnings..
I agree. They are improving their quality.

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Glass_Hero
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Posts: 114
Joined: 31 Jan 2011, 03:02
my favorite amplifier: My Glass Hero Amplification
Completed builds: 1973 Orange Graphic 120 head
Fender Champ clone head
custom Pentode input single channel 20 watt head
custom "plexi" 5 watt single ended head
custom Pentode input single channel ~2 watt combo (smaller version of my 20watt)
( i build amps and pedals )

pedal clones
Pro Co Rat
Univox SuperFuzz
Sonic Edge J&J Overdrive
Interfax Harmonic Percolator
EHX Electric Mistress
EHX Big Muff PI
EHX Big Muff into a DBA Fuzz War
Green Ringer
Orange Squeeze
Boss Slow Gear
Death By Audio Sound SAW
Death By Audio Armageddon
Death By Audio Fuzz War
MXR Phase 90
EA Tremolo
TS 808
another TS808 modded out for bass
various loop, boost, kill, stutter, feedback and signal pad stompboxes

pedal modds
big muff clipping modds and internal feedback loops w/ LDRs
EHX POG exp pedal modd
VOX 847 wah modds (expression pedals should be expressive)
Cry Baby Modds
BOSS XT-2 modds


this list is tragically outdated..
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Post by Glass_Hero »

is there any more pics of the 4 transistor model? i got the first two stages done abut after that things get weird and i cant figure it out..it looks like a mix between nyc and russian muff stages, oh and i was surprised to find the transistors in this were in forward positions..emitter to ground and collector to positive voltage..

the first stage has a gain of 15k/390, the second is 15k/100, both of these stages have feedback stabilization resistors and caps..teh third has the diodes and what appears to either be feedback or a parallel path around the tone filter to the output stage which is is up much like russian big muff.. the trimpot is like the sustain control on the muff with a resistor to ground to prevent the fuzz from grounding out the signal..

but better pics of the 4 transistor model would be nice..

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Glass_Hero
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Posts: 114
Joined: 31 Jan 2011, 03:02
my favorite amplifier: My Glass Hero Amplification
Completed builds: 1973 Orange Graphic 120 head
Fender Champ clone head
custom Pentode input single channel 20 watt head
custom "plexi" 5 watt single ended head
custom Pentode input single channel ~2 watt combo (smaller version of my 20watt)
( i build amps and pedals )

pedal clones
Pro Co Rat
Univox SuperFuzz
Sonic Edge J&J Overdrive
Interfax Harmonic Percolator
EHX Electric Mistress
EHX Big Muff PI
EHX Big Muff into a DBA Fuzz War
Green Ringer
Orange Squeeze
Boss Slow Gear
Death By Audio Sound SAW
Death By Audio Armageddon
Death By Audio Fuzz War
MXR Phase 90
EA Tremolo
TS 808
another TS808 modded out for bass
various loop, boost, kill, stutter, feedback and signal pad stompboxes

pedal modds
big muff clipping modds and internal feedback loops w/ LDRs
EHX POG exp pedal modd
VOX 847 wah modds (expression pedals should be expressive)
Cry Baby Modds
BOSS XT-2 modds


this list is tragically outdated..
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Post by Glass_Hero »

i converted my hand drawn schem to a schematic capture program.. here is the partial schem.. I didnt get the tone section figured out or the feedback/parallel path thing..

this is not a full schematic please don't flame me for posting it..it is here for reference only..

i also did not include cap & pot values..mostly because the coupling caps could be any value (in this case i am assuming they are probably 100nF but you can adjust to taste and frequency content) and because i didnt have the actual board in hand..

it kind of reminds me of a mix between NYC and Russian big muffs.. i still dont understand the feedback loop/ parallel path thing..

here is the partial schem..
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bubstance
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Post by bubstance »

So, using the pictures from headless, I've got (what I think is) a correct schematic. I got a slightly different result than Glass_Hero, mostly in the "feedback/parallel path" section; in the pictures from headless it seems to be just a 680pF cap from the second feedback loop to the output stage's input cap.

Of note is the absence of a feedback cap in the second clipping stage, which is instead replaced by a 43K resistor. Also the pulldown resistor has been moved to behind the input resistor (although it shouldn't matter).

I omitted the power filtering/polarity protection part I've been including, mostly because no one seems to like it. :lol: I kept DBA's volume control wiring as well.

If anyone spots any errors just let me know and I'll correct them. Enjoy!
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Post by Emanuele »

I think it must be some errors in the schem..the 15k resistor must be on the collector of Q3, otherwise you won't get any signal passing from that.. then the 43K resistor looks very strange to me in that position since the 470k gets useless in that way.

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Post by Nocentelli »

so in summary, is this a big muff without the second stage clippers, aka a jumbo tonebender, but with an added feedback cap and a few parts value changes)?
modman wrote: Let's hope it's not a hit, because soldering up the same pedal everyday, is a sad life. It's that same ole devilish double bind again...

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Post by bubstance »

Emanuele wrote:I think it must be some errors in the schem..the 15k resistor must be on the collector of Q3, otherwise you won't get any signal passing from that.. then the 43K resistor looks very strange to me in that position since the 470k gets useless in that way.
You're right... damn, what the hell was I thinking?

Checked and revised.
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Glass_Hero
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Posts: 114
Joined: 31 Jan 2011, 03:02
my favorite amplifier: My Glass Hero Amplification
Completed builds: 1973 Orange Graphic 120 head
Fender Champ clone head
custom Pentode input single channel 20 watt head
custom "plexi" 5 watt single ended head
custom Pentode input single channel ~2 watt combo (smaller version of my 20watt)
( i build amps and pedals )

pedal clones
Pro Co Rat
Univox SuperFuzz
Sonic Edge J&J Overdrive
Interfax Harmonic Percolator
EHX Electric Mistress
EHX Big Muff PI
EHX Big Muff into a DBA Fuzz War
Green Ringer
Orange Squeeze
Boss Slow Gear
Death By Audio Sound SAW
Death By Audio Armageddon
Death By Audio Fuzz War
MXR Phase 90
EA Tremolo
TS 808
another TS808 modded out for bass
various loop, boost, kill, stutter, feedback and signal pad stompboxes

pedal modds
big muff clipping modds and internal feedback loops w/ LDRs
EHX POG exp pedal modd
VOX 847 wah modds (expression pedals should be expressive)
Cry Baby Modds
BOSS XT-2 modds


this list is tragically outdated..
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Post by Glass_Hero »

bubstance wrote:
Emanuele wrote:I think it must be some errors in the schem..the 15k resistor must be on the collector of Q3, otherwise you won't get any signal passing from that.. then the 43K resistor looks very strange to me in that position since the 470k gets useless in that way.
You're right... damn, what the hell was I thinking?

Checked and revised.
that looks a lot better than my schem..i lost track of where some of the parts were going in the 3 stage..I think i got the 43k confused and placed it into the parallel path thing.. i made the schem quick and knew it had errors..i knew it was sloppy and not really complete.. thanks for coming up this..

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Post by ShortScaleMike »

Glass_Hero wrote:did you have the transistors in reversed? collector to ground, emitters to the positive voltage? if you had it bread-boarded and tore it apart, wait unitl we come up with the 4 transistor model it looks like a better circuit..

sorry about the tube screamer comments..i hate tube screamers, its probably the most overrated, over-cloned, over-discussed pedal on the market..
This is all in the mists of time for me now I'm afraid as it was a pretty early build for me, a few years ago now, but I think I tried the transistors both ways. I clearly didn't understand what was intended and probably didn't pursue it enough before rebiasing the stages in a more standard configuration, hence completely missing the point!

These new versions look a lot more familar to these eyes!

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Glass_Hero
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Posts: 114
Joined: 31 Jan 2011, 03:02
my favorite amplifier: My Glass Hero Amplification
Completed builds: 1973 Orange Graphic 120 head
Fender Champ clone head
custom Pentode input single channel 20 watt head
custom "plexi" 5 watt single ended head
custom Pentode input single channel ~2 watt combo (smaller version of my 20watt)
( i build amps and pedals )

pedal clones
Pro Co Rat
Univox SuperFuzz
Sonic Edge J&J Overdrive
Interfax Harmonic Percolator
EHX Electric Mistress
EHX Big Muff PI
EHX Big Muff into a DBA Fuzz War
Green Ringer
Orange Squeeze
Boss Slow Gear
Death By Audio Sound SAW
Death By Audio Armageddon
Death By Audio Fuzz War
MXR Phase 90
EA Tremolo
TS 808
another TS808 modded out for bass
various loop, boost, kill, stutter, feedback and signal pad stompboxes

pedal modds
big muff clipping modds and internal feedback loops w/ LDRs
EHX POG exp pedal modd
VOX 847 wah modds (expression pedals should be expressive)
Cry Baby Modds
BOSS XT-2 modds


this list is tragically outdated..
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Post by Glass_Hero »

i just built one..it sounds huge.. i used the armageddon filter on a second stomp and toggle for changing the clipping diodes to leds.. i also used some other big muff style mods and put in 1uF coupling caps, tweaked the tilt filter for more scoop.. bubstance's schem works :D

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Post by Zero »

bubstance wrote:
Emanuele wrote:I think it must be some errors in the schem..the 15k resistor must be on the collector of Q3, otherwise you won't get any signal passing from that.. then the 43K resistor looks very strange to me in that position since the 470k gets useless in that way.
You're right... damn, what the hell was I thinking?

Checked and revised.
Well looking at the gut shots, it seems the input is connected to the 1.5K input resistor AND the 1M pull-down resistor.
So the 1M resistor should be moved before the 1.5K resistor in the schematic.

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bubstance
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Post by bubstance »

Blammo.
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Post by Cannibal »

are you sure about the 0,1uf cap in the tone control? This would lead to an extreme mid scoop. To me 0.01uf seems more realistic but, hey, we are talking about death by audio :D
Seiche wrote:there's a difference between being drugged (I don't think it was only booze) and retarded.

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Post by bubstance »

Yep. It's labelled 104 according to the pictures.
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Post by RnFR »

after all these years, a DBA schem that actually makes sense to look at. I'm not sure if I'm sad or glad. :wink:
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Post by bubstance »

I'm curious as to the effect of the 680pF cap in that parallel path and the combination absence of feedback cap/resistor on the second stage.

Ideas?
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Glass_Hero
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Posts: 114
Joined: 31 Jan 2011, 03:02
my favorite amplifier: My Glass Hero Amplification
Completed builds: 1973 Orange Graphic 120 head
Fender Champ clone head
custom Pentode input single channel 20 watt head
custom "plexi" 5 watt single ended head
custom Pentode input single channel ~2 watt combo (smaller version of my 20watt)
( i build amps and pedals )

pedal clones
Pro Co Rat
Univox SuperFuzz
Sonic Edge J&J Overdrive
Interfax Harmonic Percolator
EHX Electric Mistress
EHX Big Muff PI
EHX Big Muff into a DBA Fuzz War
Green Ringer
Orange Squeeze
Boss Slow Gear
Death By Audio Sound SAW
Death By Audio Armageddon
Death By Audio Fuzz War
MXR Phase 90
EA Tremolo
TS 808
another TS808 modded out for bass
various loop, boost, kill, stutter, feedback and signal pad stompboxes

pedal modds
big muff clipping modds and internal feedback loops w/ LDRs
EHX POG exp pedal modd
VOX 847 wah modds (expression pedals should be expressive)
Cry Baby Modds
BOSS XT-2 modds


this list is tragically outdated..
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Post by Glass_Hero »

bubstance wrote:I'm curious as to the effect of the 680pF cap in that parallel path and the combination absence of feedback cap/resistor on the second stage.

Ideas?

the cap is a high roll off cap.. its absence retains a certain amount of high end..
http://rkerkhof.ruhosting.nl/Taas/Mods/Big%20Muff.htm


the parallel cap around the tone stack is a high pass cap, so some of the high end remains in the signal despite the tone control settings..

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Post by Emanuele »

the 680p cap is the bigger difference beetween a regolar muff, anyway it seems to me it can't do anytihing if the tone pot is on full bass..part of the highs should be grounded by the 0.1uF cap anyway..isn't it?

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Glass_Hero
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Posts: 114
Joined: 31 Jan 2011, 03:02
my favorite amplifier: My Glass Hero Amplification
Completed builds: 1973 Orange Graphic 120 head
Fender Champ clone head
custom Pentode input single channel 20 watt head
custom "plexi" 5 watt single ended head
custom Pentode input single channel ~2 watt combo (smaller version of my 20watt)
( i build amps and pedals )

pedal clones
Pro Co Rat
Univox SuperFuzz
Sonic Edge J&J Overdrive
Interfax Harmonic Percolator
EHX Electric Mistress
EHX Big Muff PI
EHX Big Muff into a DBA Fuzz War
Green Ringer
Orange Squeeze
Boss Slow Gear
Death By Audio Sound SAW
Death By Audio Armageddon
Death By Audio Fuzz War
MXR Phase 90
EA Tremolo
TS 808
another TS808 modded out for bass
various loop, boost, kill, stutter, feedback and signal pad stompboxes

pedal modds
big muff clipping modds and internal feedback loops w/ LDRs
EHX POG exp pedal modd
VOX 847 wah modds (expression pedals should be expressive)
Cry Baby Modds
BOSS XT-2 modds


this list is tragically outdated..
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Post by Glass_Hero »

Emanuele wrote:the 680p cap is the bigger difference beetween a regolar muff, anyway it seems to me it can't do anytihing if the tone pot is on full bass..part of the highs should be grounded by the 0.1uF cap anyway..isn't it?
i had an old black BMP box laying around so i built another fuzz war based only off this schem and no BMP mods..etc..or other filters..

the 680pf cap lets a portion of the high end remain throughout most of the tone rotation.. and all bass its deep and low, less than a quarter turn up the high start to bite (without the 680pf cap the highs don't come back in until about mid rotation), around mid rotation more highs and mids came in somewhere just before this.. at the high end side its cot some low/mid content with tons of biting highs..

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