Thursday, 4 October 2012

ZVex Fuzz Factory - compact layout

A more compact layout for the Fuzz Factory using radial caps, so I thought I'd add a new post rather than add it to the old layout, to avoid confusion as this one obviously isn't verified yet.

Info about the original:

This is a five-knob fuzz using two new old-stock sixties germanium transistors. The circuit is not modeled after any classic fuzz design, but should have been around when Leary was still lucid.
Although the five knobs are named for the parameters over which they seem to have the most control, please don't hold me to it. They are controls for various operating levels and biases, and basically shape you a personalized fuzz. 







136 comments:

  1. I plan to build a Factory fuzz with one pot only and the other controls as trimposts on a side. A gear called 'stupid fuzz factory' or something like that. :p

    I've never used a Fuzz Factory. What would be the best main control for a fun gear ? :)

    ReplyDelete
    Replies
    1. I've built a fuzz factory and to be honest trimpots don't sound like a good idea for this. ALL the pots are VERY interactive. You turn one and it effects the other one. This oscillates all over the place (as it's meant to) so tweaking knobs is essential when using this. You'll find yourself tweaking constantly which may be a pain if you use trimmers.

      Delete
    2. I see the point in that.. As the circuit really has something like 3 settings that are in category of "good fuzz" - rest is just oscillation and noise. :) Volume would be the only control i'd take outside the box..

      Although. That would not be very versatile and basically just waste of the circuit. If minimum control is required, i think you would be better off with a Fuzz Face/Tonebender Mk1/1.5 instead. Or just build Babylon2 or DAM Meathead. Those have only one knob.. :)
      +m

      Delete
    3. I did the very same thing you're speaking of. It wasn't so bad because I found that if I bumped a knob or something my sound was instantly bad. In the end I decided I didn't like the fuzz factory's sound anyway when comparing mine to an original. I thought I could get Fuzz Face like sounds and then go into all out crazy feedback squealing, but I couldn't. I wanted to like it so bad, but I'm much more of a vintage fuzz guy.

      Delete
    4. I suppose it's down to weather you like the oscillation. I do like it very subtle. Or just build a mammoth which swamps this in my opinion ;o)

      Delete
    5. * whether ....Damn OCD!

      Delete
  2. Thank you all.
    But my idea was not to have a fuzz factory, neither a Tonebender, Meathead or something else :
    Setting 4 value on a special fixed 'spot' where the unique control provide a really unique fuzz.

    I want a One knob gear but with easy customisation possibilities.

    (...and the idea of removing controls to a fuzz built for tweaking make me laugh too ;) )

    ReplyDelete
  3. Tag it. Works like a charm. I used my leftover AC128/AC125 (hFEs of 88 and 121) pair which i originally had soldered to the original layout that i couldn't get working back in february/march. Now this thing lauched like it should and i have to admit, the super velcro/crushed/gated sounds are not that bad. I remembered them being much worse :)
    +m

    ReplyDelete
    Replies
    1. Cool, are you boxing this one?

      Delete
    2. I think so. Although the accidental knob turns are a risk, so BB is required here :)
      +m

      Delete
    3. I've got some really small 10K pots (Alps RK09) so I reckon I could use a 1590B vertically and have all the pots at the top. I've got to build one of these for someone so I may do that instead of the usual way.

      Delete
  4. I built mine with board mounted pots horizontally in a 1590b and had a hard time squeezing everything in. Vertically seems like the way to go for maximizing space, especially if you want a battery.

    ReplyDelete
  5. Hi, does anyone know how to build this as a 2 Knob version like matt bellamy has in his guitar? 5 knobs on a guitar is a bit ott :P

    ReplyDelete
  6. Hi, I had a go at building this one (my 2nd build after the SHO), however I'm a bit confused about how the the comp pot should be wired. Because I can only fit 1 wire into the vero how should the drive and comp pots be wired up? I've tried wiring the comp pot to the drive pot but it takes away all the fuzz!

    Also I've used a 91R resistor in place of the 100R and a 5k6 instead of a 5k1, is that acceptable or would that be part of my problem? (I have a 4k3 available, would that be better than the 5k6? I'm using 1% tolerance metal film resistors.

    Just one other thing, in the diagram both transistors are labelled Q2. I have a 53hfe in the left most position and a 104hfe in the right position, is that the correct way round?

    Thanks in advance :)

    ReplyDelete
    Replies
    1. I've just noticed it says Q2 twice, I'll correct that. Yes your gains are in the correct order and your replacement values look fine. Drive 1 and Comp 3 need connecting together, so you'll go out board in the position shown, into one, then daisy chain to the next.

      Delete
  7. Thanks, I used a multilayer ceramic cap for the 100n value, would that make a difference in tone if I used a poly film capacitor? Will the replacement resistors make any difference to the sound/tone of the pedal?

    ReplyDelete
  8. Built this last night. It sounds beautiful, and the problems I had with the earlier layout are gone. This sounds amazing. Thanks!

    ReplyDelete
  9. Just built this one (third version I build by the way) for a friend, as he felt in love with this pedal when listened my unit (previous "non compact" layout).

    Used GT380B (65hfe q2 and 96hfe for Q3) and the result is superb. First time , the outboard wiring semmed to me a real pain in the ass, now, afer the Centaur and the King f Tone, seems an easy and quick wiring :P

    BR

    ReplyDelete
  10. Havin some problems with this one. The fuzz sounds great, but when i'm not playing it screeches and when i turn my volume up and down it just oscillates. any suggestions?

    ReplyDelete
    Replies
    1. No you don't. Have a problem with it i mean.
      http://www.youtube.com/watch?v=PmPg7A_MurM
      It's a feature.
      +m

      Delete
    2. that explains the oscillation part. i still need to get the screeching under control. i only had linear pots for stab and drive while i used log pots for the rest. would that make a difference?

      Delete
    3. That can only affect the feel of the sweep, so that can't be the problem. Can you describe the behaviour more? That is really noisy circuit and it can be used as a synth. Does it do that all the time? there should be about 5 different settings that do not oscillate and with those it should work pretty much as a fuzz face..
      +m

      Delete
    4. It was really just a problem when the drive was turned up all the way. i turned it down a bit and tweaked the others and the screech disappeared. i think it'll be a lot easier to control once i put some linear pots in there. i'll report back on that.

      Delete
    5. Heh. Believe me. I was just as baffled when i built my first fuzz factory :) Banged my head to the wall a lot, and then looked for some demos. That is really noisy circuit - and most of the settings are quite unusable. But the good ones are really good.
      +m

      Delete
    6. That was a bit frustrating, but it's also MUCH easier to tame with the correct taper pots. I resorted to the crappy giant RadioShack ones and they work much better! Thanks for the help, Miro!

      Delete
  11. Some some stupid reason i put it in a big box...
    http://mirosol.kapsi.fi/varasto/boxes/factsoffuzz.JPG
    +m

    ReplyDelete
  12. anyone have any good suggestions for equivalents for the ac128? i just ordered some on ebay, but theyre coming from bulgaria, and i wanted to wire one up to with something close to compare. thanks!

    ReplyDelete
    Replies
    1. Zack also uses the 2N404 in the Fuzz Factory sometimes so that would be a good choice. Basically any PNP germanium will do the trick though.

      Delete
  13. Hello,
    can i use a boss style power supply with this circuit or to do that i must add a daughter board to make a negative voltage inverter?

    ReplyDelete
    Replies
    1. No you don't. This is negative ground circuit, even though it has 2 PNP transistors. So normal, boss standard will suffice.
      +m

      Delete
    2. Ok, thanks for your reply.
      I will have to give this a try.

      Delete
  14. Hi guys, is that correct that to gate 1 and 2 there is nothing connected?

    Thanks
    Pier

    ReplyDelete
    Replies
    1. There's a note at the bottom, Gate 1 & 2 to ground.

      Delete
  15. True! Thanks for replying so quickly :)
    Pier

    ReplyDelete
  16. Past evening built another one.

    Well, it works, but this time, it oscillates bit TOOOOO much. With Gate and Comp fully CCW and Stab fully cranked, can't get Drive knob beyonf 2 / 3 o'clock without getting hard oscillation.

    In other builds, this is a basic setup to emulate a classic fuzz, and Drive can be fully cranked.

    Any idea about what can be wrong? I've used several pairs of trannies (from 40-55hfe to 75-100) and the behaviour is the same.

    BR

    ReplyDelete
    Replies
    1. By the way, not only for this build, but for previous ones too, I'm afraid that the Stab pot is reversed. In all F. Factory demos, the Stab know if fully turn CW in order to "stop" oscillations, and has to be turned CCW to get crazy sounds. Wiring like this vero shows, gets the opposite behaviour. Don't think is very important, but want to comment it out.

      BR

      Delete
    2. Yep Stab is definitely reversed. Built it from this and I own a Zvex aswell

      Delete
  17. Could somebody please explain to me what this "hFE" value means, and which value I should use for the two transistors in this circuit? Thanks!

    ReplyDelete
    Replies
    1. hfe is the transistors measured gain. A good Fuzz Face pair should be good in this, and so around 70-90 for Q2, 110-130 for Q3.

      Delete
  18. Just a slight improvement to this circuit, try using a 10k log pot instead of the 5k linear, this reduces the maximum volume (which is far too loud) to something a bit more useable and also improves the sweep.
    Thanks
    Dave

    ReplyDelete
  19. Ok, so another question. I found on some forum that to get a thicker sound (more bass), you could replace the 10u output cap with a 22u output cap.

    Now, this might be a stupid question, but: the output cap is the electrolytic cap that is directly connected with the output, right? So in this layout, you have three electrolytic 10u caps, and the output cap would be the middle one?

    ReplyDelete
    Replies
    1. Yes it's the 10u cap at the output connection underneath Q3 (marked Q2 on the layout and now corrected). A 22u cap would in theory let more bass out of the circuit, but 10u is pretty big anyway and so it may already be letting out the full range. Personally if I wanted more bass I'd consider tacking a simple tone control on at the end like the Stupidly Wonderful Tone Control in between the 5K1 and the Volume pot. Like this:

      http://www.muzique.com/lab/swtc.htm

      You could even make that up with a trimmer on a small piece of vero and keep in internal as a set and forget base tone control.

      Delete
    2. Thanks for the suggestion. However, I'm going to use a toggleswitch to choose between "standard" (10u) and "more bass" (22u). I'll let you know how it turns out :)

      Delete
    3. Ok, so first of all, this sounds amazing. I have owned a vexter fuzz factory, which I sold because in any setting it sounded too thin and trebly to be of any use. However, this circuit, MUCH beefier, but with the same whacky noises.

      Changing the cap to 22u doesn't seem to change anything to my ears. Maybe if you use it with bass you could hear it, I'm not sure... If there is a difference, it's rather subtle.

      Delete
    4. This comment has been removed by the author.

      Delete
    5. I would also be interested in the addition of a tone control to be able to roll of treble.

      Does anyone know what the tone control is that Zvex added to the more elaborate FF7? Supposedly it works quite nicely.

      Or alternatively, what would be good values pot and cap values to in this circuit with the SWTC as described above, also taking the 5K1 in consideration.

      Delete
  20. There are 3 grounds on the circuit. Help? Where does each one go specifically?

    ReplyDelete
    Replies
    1. All the grounds connect together along with the negative lug of the DC socket and the input/output sleeves etc. Probably be easiest to take them all to the input sleeve

      Delete
    2. So the input jack is stereo?

      Delete
    3. Only if you want to use a battery. I only use mono because I never include a battery snap.

      Delete
  21. Just finished mine. It doesn't oscilate. I didn't find any errors. Can it be because I'm powering it with a batery? Gate pot has a strange behaviour but aparently strange is normal for this pedal.

    Any thoughts?

    ReplyDelete
    Replies
    1. Regardless of settings? It only oscillates ( slightly, or out of control ) on certain combinations of settings of the controls. I like the fuzz sound in some of the more oscillating settings of the controls. Trouble is, you can't stop playing or the oscillating sets in...so I just keep playing....

      Delete
  22. Yup, regardless of settings. I've got it all: Velcro, normal fuzz, "Knights of cydonia" Fuzz, etc, but no oscilation.

    ReplyDelete
  23. mine works exactly like the original and sounds great. I also added a switch to be able to have less fuzz (gain), which also allows me to dial in a darker fuzz for use with a bass.

    pics:

    http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/FuzzFact/F-Fact-01.jpg

    gut shot:

    http://johnkvintageguitars.homestead.com/Effects/Fuzz-ODs/FuzzFact/F-Fact-02.jpg

    ReplyDelete
    Replies
    1. Hi John,

      What is that switch connected to?
      Thanks

      Delete
    2. it just trims the input for lower gain.

      Delete
    3. Hola John Kallas, estoy armando me un fuzz factory con el mismo esquema que tu utilizaste pero no logro conseguir el sonido adecuado el pot "gate" al ponerlo al maximo pone el pedal en "mute absoluto", creo que todo el problema esta en el cableado externo, es decir del circuito a los pots y al 3dpt, me podrias enviar un diagrama de como cableaste los pots? muchas gracias y saludos desde México

      Delete
    4. translation:
      "Hello John Kallas, I'm putting together me a fuzz factory with the same schema as your you used but I can not get the sound suitable the pot 'gate' to put it to the maximum pedal it becomes 'absolute mute', I think that the whole problem is in the external wiring, i.e. the circuit to the pots and the 3dpt, I could send a diagram of as cableaste the pots? Thank you and greetings from Mexico"

      i'd have to check mine again, but the gate 'could' possibly mute the pedal if your input signal isn't hot enough.
      check this demo to see how it's supposed to sound.
      https://www.youtube.com/watch?v=JVceBkgsDME

      Delete
    5. Gracias John he visto el video y mi pedal no se escucha nada igual al original, volvere a conectar todos los cables desde el principio. seguro algo he hecho mal, seguire intentando, gracias amigo

      Delete
  24. Hi guys, built this and sounds perfect thanx. I would say that in testing a whole load of AC128s in this circuit i've discovered that they make the most difference to the final tone. Some sound great but others can be weak and tinny and don't oscillate at all. So if people are having trouble accessing all of the tones try some new trannies!
    I've been looking around of late for a layout or schematic of the new fat fuzz factory, basically i want to know which component is being switched? I can only assume there are 3 cap values on the new DPDT (on-off-on) which replace the 100n. I think the in/out caps are already massive so switching these would do very little, so process of elimination says the only other cap must be the one!? Complete guess again :) does anybody out there know any better? Cheers

    ReplyDelete
    Replies
    1. Hey! Thanks for the trannie advice, I'll socket them in my next build.

      I'm also on the hunt for a way to build the new fat fuzz factory, did you ever find out what its deal was? Have you seen a schem, gutshot or vero of it yet? I'd love to add one to my weird bass rig...

      Delete
  25. I've built this on a WOOD box! =D
    http://imageshack.us/g/811/u5we.jpg/

    The finished pedal: http://imageshack.us/photo/my-images/811/u5we.jpg/
    Gutshot #1: http://imageshack.us/photo/my-images/811/1bar.jpg/
    Gutshot #2 with germanium transistors from USSR: http://imageshack.us/photo/my-images/594/27j0.jpg/

    \__/_

    ReplyDelete
  26. ...and I made a review from this pedal built by Ugo Sangiorgi! Check it out:
    http://www.youtube.com/watch?v=JSX5fsSoh-E&feature=youtu.be

    ReplyDelete
  27. can someone pls. tell me where to buy matched Ge transistors that would definitely work in this Layout?

    ReplyDelete
  28. I just brought 4 ac128 transistors for mine and randomly picked two, probably not the best method but it works and sounds spot on so maybe matching isn't as critical as you may think.
    Cheers
    Dave

    ReplyDelete
    Replies
    1. Thanks Dave I did the same thing but no luck :(
      now i'm thinking between low medium of high gain matched set for fuzz face so if someone can hellp me decide
      http://www.banzaimusic.com/search.php?mode=search&page=1

      Delete
  29. finished like this sound,,
    this is matt belamy in song plug in baby,, nice :D
    thank Ivlark

    ReplyDelete
  30. quick question can i use oc 75 in this they are also pnp?? or do they have to have -9 insted of +9 ?

    ReplyDelete
  31. i love this circuit, but it has entirely way too much output- even all of the official zvex settings have the volume at 10 oclock. would messing with the 5.1k resistor and 5k pot affect the circuit negatively?

    ReplyDelete
    Replies
    1. I'm with you on that, the volume knob is so touchy its damn near unusable. I would think just using a larger value pot would sort that out, try 50k or 100k. Putting more resistance between the circuit and output should make it quieter and more usable. Let me know the outcome if you do this, as I'm about to rebuild my fuzz factory.
      Thanks
      Dave

      Delete
    2. Actually, bigger value will make it louder. There will be more resistance in series, but that won't contribute in lower level. The volume control sort of mixes the output with ground, so you'd end up with more volume when the resistance between ground and output grows. You could just try 10K log taper there instead. Or probably 5K to cut the sweep in half.

      Original is as loud as all the clone circuits i've built, so that is an feature.
      +m

      Delete
    3. Really? I always thought that a volume knob essentially attenuates the output, thus more resistance=more attenuation of signal=less volume?
      In that case, sure it'd just make sense to up that 5k1 resistor?
      Thanks
      Dave

      Delete
    4. That's my perception of the theory. You should try it. :) Luckily the volume control and the components around that aren't affecting the Q3, so it's safe to experiment without changing the tone.

      More resistance attenuates it, yes, but the main thing is to "mix" it with goung. You should also try bigger value for the 5K1. Althogh (i was wrong earlier with my 10K comment), 5K log taper should give you better feel for the volume knob. I would try that first.
      +m

      Delete
  32. Hey guys,

    I am building this and having a bit of trouble. I finished wiring it into the enclosure. I have bypass signal when power is both supplied and not supplied, but nothing when the effect is engaged. I have checked it with an Audio probe, and i am not even getting any signal from the input jack tip. When i check it in bypass mode, I get signal all the way from the input to the output. I am unsure what they problem could be. All i could see it being is a grounding issue is shorting the pedal.
    Does anyone know? I know this question doesnt specifically belong in this section, however this is the pedal I am building......

    Thanks in advance.

    ReplyDelete
    Replies
    1. Sounds like your circuit input is grounded. That explains it.
      +m

      Delete
    2. Cheers man!

      Excuse my ignorance, but how would I be able to solve this problem? I will research the issue, but any help is greatly appreciated!

      Delete
    3. You must have some sort of short circuit either at the switch or at the circuit board input. Either of those are grounding your input. Other chance is that there is voltage leaking to the input. The result would be the same.
      +m

      Delete
    4. Ok, I have had a look, and fixed it to a point where i now have an output. However, there is no note definition, and now actual guitar sound. The pots are all interacting as expected, but no guitar notes. What do you think this could be?

      Delete
    5. Hi, did you find out what the problem was? I'm having the same problem.

      Delete
  33. Hello,

    I finished a fuzz factory. However, I have a problem. I do not have enough gain, plugged directly into the amp, it is rather an overdrive. I need the boost with my RC booster (thank you for the vero!) and it's fuzz. I would add that the gain knob does not really affect. Basically nothing to do with the video posted.

    Initially I had two AC128 with a hfe of 70 and the other 90. I thought the second would not be strong enough, so I put an AC180 with a hfe of 120. But still little gain.

    I checked the circuit again and again and I still can not see. Ideas? Thank you in advance and sorry for my crappy google translation

    ReplyDelete
    Replies
    1. Same problem, did you find the solution?

      Delete
    2. If the components all measure ok then you've got a bad connection somewhere. Definitely a build or component related issue and 90% of the time it's a bad solder joint or connection, or an unwanted bridge/incomplete cut etc.

      Delete
    3. Thanks IvIark, finally I just take the AC28, put the leg really straight and put again on the pedal and now it's work completely. I don't know what transistor I've to put on the left and right position (mines are 70HFE and 90HFE). Probably a 2 legs were in contact or something like that now it works great.

      Delete
  34. I have a little problem with DPDT and led, while FX positions off there is a little fuzz sound to be clean, you have a DPDT wiring for fuzz factory?

    ReplyDelete
  35. i want to build this into a gutted crybaby, and use the stab pot as the foot control, but the pot is a 100k, and i can't seem to find a crybaby adapter to use a normal pot. my question is, how, if at all, do i make a 100k pot(stock) to a 5k that this circuit calls for?

    ReplyDelete
    Replies
    1. If I'm right you can reduce the value of a pot by placing some other resistors right on the pot between pin 1 and pin 3, Example if you have a 500k pot and put a 2m resistor across 1&3 it will then register as a 250k pot. There is no reason you couldnt then add another resistor in parallel to decrease it even further. Break out a multimeter and test it ;)

      Delete
    2. Yes just put a 5K resistor between lugs 1 and 3. That will give you around 5K, or close enough.

      Delete
  36. Can anyone explain why none of schematics on the web show that 100R from the 9V to the STAB pot?

    ReplyDelete
  37. I think you can find the 100R here:

    http://www.zvex.com/module_instructions.pdf

    ReplyDelete
  38. Hi,

    I'm having trouble getting this to sound just right. In my opinion I'm getting too much oscillation way too early (compared to some vids on youtube).

    For example with Gate, Comp, Drive at "Noon" and Stab fully to the right it's already squealing like hell. Turning Stab to the left just makes it worse, so the wiring of the pot should be ok. Should I get oscillation with the stab knob fully to the right ?
    The official Zvex settings sound nothing like they should, neither. Tweaking the knobs, I'm getting usable tones, it just never sounds like in the videos.

    I double and triple checked the values of the caps (for one of the 10u caps I used two 4,7u soldered together in parallel), resistors and pots. Checked the pot wiring a few times (used the 3-2-1 convention looking at the back of the pots). It all looks good imho.

    Q2 and Q3 have an hfe of 78 and 103. I don't have the equipment to measure them, so I have to trust the ebay seller. Those values should be ok, I guess.

    Oh, and I found out that I can change the orientation of Q1 (2N3904) from CBE to EBC and still get similar sounds both times. Is this normal behaviour for Q1?

    Did anyone else have similar problems ?

    THX in advance !

    ReplyDelete
    Replies
    1. some gut shots:

      http://abload.de/img/img_20140402_135526bjujx.jpg
      http://abload.de/img/img_20140402_135652vuuy7.jpg
      http://abload.de/img/img_20140402_135828ycuwf.jpg
      http://abload.de/img/img_20140402_135924nmudi.jpg

      Delete
    2. The problem with something that is designed to oscillate is that you can't tell whether the osc is as intended or you're getting interference from anywhere else.

      Make sure the input and output wires are well separated in the box and see if that affects the amount of osc you're getting. Other measures you can try is putting a low value resistor such as 100 ohms in series with the input and supply. And a low value cap such as 100p between input wire and ground can help minimise RF interference.

      Those are the things I would try first

      Delete
    3. Just noticed your pics. You're going to get a lot more noise as it is at the moment because the box will act as a shield when it's boxed up. That would actually be the first thing I would try.

      Delete
    4. I'll box it up and see how it reacts then, should have been the obvious next step,
      I guess :D

      If it still sounds weird I'll try your other suggestions.

      Thank you !

      Delete
    5. I just noticed this already has a 100R resistor at the supply so you can forget that stage.

      I always suggest people make sure an effect is working before connecting a switch or boxing, but with oscillation you really have to just get it boxed. As long as you can tell that all the pots are working correctly and in the right direction, and it's only noise causing an issue, then just box it and see how you get on.

      You will definitely get less noise when boxed, but another option to reduce it further if it's still not quiet enough is to try a filter cap between supply and ground. Something like 47u should help without being too much to tame the fuzz.

      Delete
    6. Found an old box with a few more holes than needed, put it in and....voila, it's working perfectly now.

      I never really thought that shielding (or lack of) might cause those problems, because probably all of the circuits I built from this site worked perfectly with and without boxing them.

      Awesome !

      Delete
  39. no idea why i didn't build it months ago...fantastic sounds in it! A real factory! and it works with two 2n3906 too!that's the only pnp i had home so i tried them...can't wait to put some germanium pnp in there but it's too difficult to find in my town...and i don't feel like ordering again...thanks Mark!you're the man!

    ReplyDelete
  40. So i built this circuit. Not working as it should. None of the pots work and have a very bad gate affect when playing. I did not use ac128 but replaced them with 2n3906's. Did not have 100R so combined two 47R in series. What could cause the gating effect ? Also as soon as i connect the two pots lugs to ground the effect stops working and no sound comes out..

    ReplyDelete
    Replies
    1. You're not using the right transistors, and although you can use silicon transistors to check that a circuit works, there's no way I would expect the results to sound like an original Fuzz Factory. The Gate pot should help bias Q2, and the Comp pot Q3, but the circuit was designed with germanium transistors with a Fuzz Face sort of gain and so isn't in any way optimised for the transistors you've used.

      Personally I'd get 10 Russian GT308Vs or similar off eBay, they'll cheap and will sound much better in this.

      Delete
  41. Hi, I've built this pedal but I don't get any sound. Only a slight clean signal.
    I've used two Ac128 and a 2n3904.
    Values are (C-B-E Voltage order):
    Q1: 0,7 / 0,6 0
    Q2: 0,47 / 2,8 / 2,9
    Q3: 0,6 / 0,47 / 0,66

    None of the pots do something. So hope anyone has a suggestion about what it could be.

    ReplyDelete
    Replies
    1. Q1 collector and Q2 and Q3 emitter voltages are too low. It may sound daft but is the Stab control right down? If the voltage isn't getting to the circuit then the pot must either be down, or you have a bad connection in the 9V or stab connections, or maybe even a faulty pot.

      Delete
    2. I tried a new pot but no changes. What I did discover is something strange. The row of Volume 2 (half of untill the cut) is connected to the ground. It's the only place which is connected to the ground, The rest of the rows are okay. But I knifed in between and I'm very sure that there's no connection between the rows. I have no clue what it could be. The 10u Cap is not putting the ground signal through either from another row or something. So strange. Any ideas?

      Wireless grounding wonder?

      Delete
  42. This is a great project and I think i will love you for all my life, but I have one question:

    how I can get more basses? Replacing in/out caps(I thought with 22uf/47uf) or that 100nf with higher(or lower?) value? I don't know very well but replacing with a lower value I guess the sound will be more squeeze... mmm

    ReplyDelete
    Replies
    1. This is a pretty simple circuit, basically just a booster into a Fuzz Face and there isn't a lot of places where the bass content can be affected. The 10u input and output caps will let all low frequencies in and out and so increasing those won't make a difference. The only area that you may be cutting some low end is the 100n cap and so you could try increasing that. I'm not convinced that will make too much difference either though.

      To get the bass content you want, you may want to try an active tone control like an EQ so you can get a real boost in the low frequencies.

      Delete
    2. I've tried to increase the 100nf until 1uf and actually have more basses. I reccomend this mod if you want use the Fuzz Factory with bass, it's a pretty good sound.
      I guess this is the same mod for the Fat Fuzz Factory.

      Delete
  43. I have this built finished it last night. Add me to the list of people who think the oscillation is out of control. Anything I can adjust to tame this thing Down? I can barely move the dials past quarter of the way...does not react like it does in the demo...Just has WILD oscillation when you're not playing.I had to sub a 1.2m in place of the 1m... but I don't think that's the issue.

    ReplyDelete
  44. For those looking for the "fat fuzz factory layout":
    http://www.guitarristas.info/index.php?controller=forum&action=view_attachment&attachment_id=48818
    ;)

    ReplyDelete
  45. As JaviCAP said on 27th December 2012, I think the STAB pot is reverse...

    ReplyDelete
  46. Or better, I think Stab 1&2 to Drive 1 and Comp 1&2.
    Drive 3 to Comp 3.
    Also Vol1 and Gate 3 to GND and Gate 1&2 on the first stripe....
    In this way all the settings here http://media1.zvex.com/FLASH/fuzzfactory/ are very similar! :D

    ReplyDelete
  47. Just built my first fuzz factory circuit and testing with alligator clips went great. I was sitting with my headphones playing guitar and twisting the knobs for hours. It's insane how many sounds this circuit can produce. Playing with my les Paul with neck himbucker selected sounded extremely beefy and with some settings it sounded suby almost like a bass. Now to box it... I'm too afraid to try and fit this into 1590b so I guess I'll try a 125b or maybe even a 1590s

    ReplyDelete
    Replies
    1. Don't worry, it easily fits in a 1590B :)

      Delete
  48. This comment has been removed by the author.

    ReplyDelete
  49. Alright 1590b it is then. I had a question about wiring drive and comp pots though. Going from the circuit, do I wire them in parallel or series? In my test I had them two in parallel and it worked, but when boxing ird be easier to wire in series. Would that make any difference?

    ReplyDelete
    Replies
    1. From stripboard to drive1, then from drive1 to comp3. The same for the other pot

      Delete
  50. For those who want to tame the oscillations a little, Nels Cline runs a buffered pedal before the FF in the chain and says that helps control it a little. I haven't tried it, but something like the Mad Professor Ruby Red Booster with a switchable buffer might be a great choice to run before the Fuzz Factory. I'll be building an FF soon and can report back.

    ReplyDelete
  51. This comment has been removed by the author.

    ReplyDelete
  52. My build isn't working so I did a probe and got a quieter and buzzy signal after the 10k resistor. I checked that value with a multimeter (I'm guessing that its not the most accurate way to test) and got a value still close to 10k. Would it be Q2 that is giving me issues or is there supposed to be a drop in signal there?

    ReplyDelete
    Replies
    1. I have a similar issue, the sound is very gated even with Comp and Gate fully CCW. I've built one before and it worked well. I'm pretty sure the transistors I put in the second one are the wrong hfe and end up spitting out this misbiased fuzzy mess of a signal. With Drive fully CCW it's still very fuzzy and there's no oscillation whatsoever. Sucks!

      Delete
  53. I have to use negative ground power supply or postive ground with this power supply with this pedal?

    ReplyDelete
  54. Can i replace AC128 with AC132 or AC176? I can't find anywhere to buy AC128 transistors.

    ReplyDelete
    Replies
    1. or with BC558 silicon alternative

      Delete
    2. AC128 are widely available on eBay. You can try any PNP germanium, but you're probably going to want something with low leakage and hfe between 70-120. You could use a fuzz face set from smallbear

      The AC176 is NPN so it won't work here. The BC558 won't sound right.

      The AC132 could work but looking at the datasheet it doesn't seem like a great choice

      Delete
    3. Unfortunately i live in Greece so buying from smallbear will cost me a fortune. That's why i am trying to find an alternative.

      The BC558 was suggested as alternative for the AC128 for this layout(at reddit) that's why i asked.

      Delete
    4. 2n5087 works extremely well as a silicon alternative. i used them in my build and the circuit sounds great and reacts the same way as the zvex fuzz factory (i've owned three).

      Delete
    5. hi mate.
      where are you in greece?i'm in thessaloniki and i have some ac128, and other germanium transistors.

      also i'm with Travis on this...if you've read the comments above, i've build this when i didn't have any germaniums, and used 2n3906...it will work but believe me...when you'll put the ac128 inside, then it will work for real...!!! mine turn out really really good...

      Delete
    6. hi mate ,
      i live in athens. Checked ebay and for 2 ac128 it will cost me something around 20 euros(too much for me right now) so i am thinking of buying these http://4.bp.blogspot.com/-zyvgGD0xKNE/T6QHFyvuRKI/AAAAAAAABbs/HlvgHecK6Qo/s1600/Header.jpg and put BC558 or 2n3906 s and when i ll be able to buy the ac128 just replace them.

      Delete
  55. The BC558 datasheet shows a max hfe of 150 which puts it in the right sort of hfe range theoretically but if you want this to sound and behave like the fuzz factory then I suggest you get some germanium transistors similar to the ones used in the original.

    I live in the USA so I don't know what it's like in Greece really but Russian germaniums are the cheapest out there and there are several which will work well here. MP20A and IT308V are a couple good ones to try. You should check out ebay because the regular electronic part store websites don't usually carry obsolete parts such as germanium transistors. If they do have them it tends to be a bad selection with bad prices

    ReplyDelete
  56. Hey there !

    Made this layout, and it sounds awesome !
    It reacts like a real FF :)
    Thx a lot !!!

    Cheers

    ReplyDelete