Fuzz Factory not working?

[vendettav]

Hey guys, as some of you may know, these few days i've been preparing for the fuzz factory build

now i fibnalyl got the parts and put it all together on the breadboard and it doesnt work.
I built it from this http://solgrind.files.wordpress.com/2008/02/zvex-fuzzfactory-rev1-1.gif
and the question is is it a legit schematic?

it does give the guitar sound but i dont know it's nothing close to fuzz (almost clean guitar) and it doesnt do anything that fuzz factory is supposed to do... the only sub'd parts are the 220k resistor at the output (to the ground) which is 240, the 2 Ge transistors which are BC558.

also the pots, couldn't get any 10 or 5 k pots so i took 20ks and put 3 10k resistors across the three of them for 10k pots and 2 7.5k for two 5k pots.. do you think this could lead to the fail?


anyways guys help me figure out what could i have done wrong?? I am mainly suspecting the schematic.

[CynicalMan]

The schematic is correct. What are your voltages?

[vendettav]

ok btw i tested the hFE of the BC558 and it's around 380. that seems a bit too much but i guess it has to work since everybody says BC558 work just fine

the voltages are

Q1 2n3904

C 2
B 0.67
E 0

(this for some reason doesn't look good to me)

Q2 (the left BC558)

E 10.8
B 10.3
C 4.4

Q2 (the right BC558)

E 4.7~ (this one was going up and down: 4.1-7
B 4
C 4.94

[vendettav]

anybody help please??

[MikeH]

I've never been able to get this circuit to work with just any old transistor set.  I think the gain needs to be pretty high.  I tried with a Fuzz Face set from small bear and got similar results to what you have.  I ended up buying a "fuzz factory" matched set from the guy in the Czech Republic off of ebay.  Those worked great, but it cost 15 bucks to get them into my hands.

[vendettav]

hmm, im still sure there's something wrong with something else, not the trannies.
the hFE  gain is about 380 which is huge and actually one is 380 and other is 379 so they're quite close

I'm thinking of putting it on a vero board and going from there may be... but \, shall i take the pots back to the store  and wait till they get the proper values? or shall i stay with the Parallel resistor thing? Im guess thing that mkes a pot B type (linear) but I already have B and the schematic requires B

[Scruffie]

I'm probably responsible for the BC558 thing going around, I tried them in my Fuzz Factory clone way back when and compared to my real Fuzz Factory, they sounded the same enough to me, some people don't like them though, any PNP Silicon will work fine probably... they even work alright backwards for about 6 months as I found out  

I don't think the Pot Value and Taper is gunna make that bigger difference to you... and parallel resistors should remove any problems, they wont make the pots not work unless... you soldered them to the pots and got solder inside the back in the mechanism, which can happen.

[vendettav]

hmmm i still don't get what's the problem... idk but do the NPN tranny's voltages look wrong???

the thing does have a very slight fuzz but nowhere close to what it has to be ... it's tooo slight...

I'll see if I can put it on a vero (so I'm sure i havent messed up the breadboarding part) from that layout available online
hopefully it'll work this time, but anyways keep the ideas coming, they're useful

ahh if i can build this...I've been dreaming for one for awhile now

[CynicalMan]

The collector voltage on the last transistor looks wrong to me. It should be lower than the emitter.

[vendettav]

so the rest does look cool?

I'll check to see if there's some mistake or something there:)

[LucifersTrip]

I used gains of  ~ 65, 96 for Q2, Q3, similar to what would work in a Fuzz Face ...and I used the exact same schematic.

the thread is here:
http://www.diystompboxes.com/smfforum/index.php?topic=87177.0

[vendettav]

yeah i've seen that thread... hmm I don't think i'll be able to go close to that value... all ive got is around 200-300

but i see a lot of people in here did it with BC558

idk what to think about anymore.. I'll do the vero tonight...

[vendettav]

anybody has tried BC558?