Death By Audio Fuzz War 7 transistor version

[anders]

BOM!
Verified vero with some tweaks and mods.

[Travis]

Great work Anders! I haven't built any of your layouts yet, but it seems that we have similar taste in pedals (fuzz!). I really appreciate the contributions you've been making here

So which parts of this have been changed from the original?

[anders]

Thanks! The major change I did was upping the values of the 430k resistors that goes from 9v rail to base of the 5 first transistors to 820k. That eliminated the gating completely. A minor change I did was to sub the two 910k resistors to 1 M Ohm simply because I didn't had any. Tried several transistors, 2N3904, MPSA18 and 2N5088. Don't have any 2N5089 at the moment but will try as soon as I get any, but 2N5088 sounds best to me so far.

I went with 680nf caps as the oldest version has. Was unsure about the 680pf cap in the tone section, I haven't seen a confirmed value yet but went with 680pf because it's in johnk's layout.

Uhm, that's it!

[rocket88]

Looks great man. Got to ask one thing since there was a lot of issues with some peoples builds of this from johnk's layout. What voltages are you getting. I remember someone saying they could get it to work right when they biased the transistors they could only get it to work with ~1.5V as opposed to the more common 4.5V. Definitely looking at building this, the older 7 transistor version and newer 4 transistor one. Very curious at how they compare sound wise. Awesome job.

[anders]

Sure, will do after work tomorrow.

[anders]

Noob question...I'm about to meassure the voltages of transistors firts time ever. Where do I put the red and the black wires of the multimeter?

[rocket88]

Red to the transistor legs, black to ground. If I'm testing in an enclose I usually put the black into one of the screw holes.

[anders]

Ok, here is the voltages...
Q1
E 1,78
B 0,58
C 0,03

Q2
E 1,58
B 0,58
C 0,03

Q3
E 1,38
B 0,57
C 0,03

Q4
E 1,89
B 0,58
B 0,03

Q5
E 1,24
B 0,57
C 0,02

Q6
E 0,56
B 0,56
C 0,02

Q7
E 0,15
B 0,56
C 0,02

[rocket88]

Interesting. It's super low voltage, 1.5V. This might explain the trouble people have building this

[IvIark]

Nice job anders, thanks for sharing

[anders]

Built another one today with 100nf caps instead of 680nf caps and it's differs quite a bit. With the 680nf cap version you have to fight to control it while with 100nf caps it's a bit less unruly and and less noisy. I also omitted the trimmer and went with an external Drive pot and it's works ok, it goes from fuzz to more fuzz with a bit added noise. For the diodes I used D9D's which is less gritty than the D112's I used in the 680nf cap version.

[Tune Tone]

quick question:
I'm having terrible crackle scratchy sounds with either the drive trimmer / fuzz knob. dosnt matter which I chose to put when turning I get horrible noise which apparently do not relay on the pots (I tried like 4 different ones with different values as well)
SO I figure out it must be something within' the circuit ? this is the pot / trimmer that sets the bias of the tranis is it ? so maybe you can not avoid the noise ?

thanks!!

[Tune Tone]

[tabbycat]

many thanks for the post anders. damn, i thought i had hit peak fuzz and could move onto synth.

[anders]

My "Drive" pot is very noisy as well. I haven't played a real Fuzz War  so I don't know if it's something wrong or if it should be noisy.
I have played around more with this circuit and the 27k resistor and the two diodes next to Q6 is quite useles. Snipped them of and noticed no change in the sound except for a volume boost.

[ryder17]

Anders, kudos to you sir! I built this and have been having a lot of trouble with it, until I found your posts. The 820k's have got me up and running. The only trouble I'm having is that it's very noisy when I'm not playing, a fizzy kinda gurgle. Are you getting this too or have I gotten something wrong?

[btthrt]

You are not alone, ryder.
I've got a noise issue too when the pedal is powered with 9v isolated power supply.
No hum or fizz when using battery.

Still can't figure what's a problem. Gonna play a bit with input voltage.

[anders]

Sorry for the late reply. Yes mine behaves quite erratic as well especially the one with 680nF caps. It all depends how you set the trimmer or drive pot, in some settings it's swells and feedback on it's own. If you want to tame it try 680k or 750k resistors instead of 820k and replace all the 680nF caps with 100nF caps.

As for the noise regarding the power supply, solder a 100uF cap between ground and power rail.

A friend of mine requested a Fuzz War and here is what a I did:

[btthrt]

Hi Anders,

I tried adding 100uf-220uf cap between 9v and ground, but it only changet a tonality of the hum and lowered it a bit.

[btthrt]

Hi Anders

Do you have any updates to your layout?
I've tried the last one multiple times and it seems faulty. I mean, it's not working at all. I hear crackle from vol pot and my voltages meet yours but only when the power is reversedl.