Zvex - Fuzz Factory  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
User avatar
poodlebra
Breadboard Brother
Information
Posts: 67
Joined: 20 Feb 2010, 12:15
Has thanked: 1 time
Been thanked: 1 time

Post by poodlebra »

or if you're in the uk i have a bunch of 404 and 128. ebay user: chakkaboom

User avatar
Scruffie
Opamp Operator
Information
Posts: 1739
Joined: 13 Mar 2009, 17:59
Location: UK
Has thanked: 28 times
Been thanked: 170 times

Post by Scruffie »

ckyvick wrote:
westarttodrift wrote:Can you conceivably swap out Silicon Transistors and make an otherwise stock Fuzz Factory? If so, which SI transistors work best in the circuit?
it would work just not the way germaniums would. You can get some cheap ge's that are perfect for this circuit from a number of sources(capsnsuch.com)
I used Silicons and tested it next to my actual Fuzz factory, not enough difference to worry over, but also, it'll take near any germaniums so that's always an option.

User avatar
Jaicen
Breadboard Brother
Information
Posts: 86
Joined: 28 Mar 2008, 21:12
Location: South Yorkshire
Has thanked: 1 time

Post by Jaicen »

Agreed, there's very little difference between Ge and Si in this circuit, they're both very bright.
That said, some leaky Ge I tried did sound particularly nice, but in the context of a band, you literally will not be able to tell the difference.
FWIW, 2N3906 sound just fine.

User avatar
westarttodrift
Information
Posts: 20
Joined: 15 Oct 2010, 22:22

Post by westarttodrift »

Jaicen wrote:Agreed, there's very little difference between Ge and Si in this circuit, they're both very bright.
That said, some leaky Ge I tried did sound particularly nice, but in the context of a band, you literally will not be able to tell the difference.
FWIW, 2N3906 sound just fine.
Okay cool, thats what I was thinking of throwing in there. Thanks!

User avatar
bobbybrenes
Information
Posts: 2
Joined: 24 Nov 2010, 08:17

Post by bobbybrenes »

Hi, I am going to start and build the FF as my first DIY stompbox, as I think it is relatively simple and a cool effect.I don't want to wire a DC jack in my pedal, since I only use batteries and I am using this layout: http://www.matsumin.net/diy/jisaku1/fuz ... layout.gif

How can I wire the battery to the pot and the LED so that I don't have to wire the DC jack? Also, what should be the forward current and the voltage for the LED? Also, what should be the power rating for the resistors? I was thinking 1/2 watt would be okay.

Thanks in advance!

User avatar
Renegadrian
Solder Soldier
Information
Posts: 180
Joined: 19 Aug 2008, 20:29
Has thanked: 15 times
Been thanked: 15 times

Post by Renegadrian »

1/4W resistors and you save space. they are fine for all battery powered circuits.

User avatar
bobbybrenes
Information
Posts: 2
Joined: 24 Nov 2010, 08:17

Post by bobbybrenes »

Another quick question, as you know I am quite a noob with these projects so I still need some experience. Would 16V electrolytic capacitors work or do I need one with a higher working voltage?

User avatar
Renegadrian
Solder Soldier
Information
Posts: 180
Joined: 19 Aug 2008, 20:29
Has thanked: 15 times
Been thanked: 15 times

Post by Renegadrian »

go for them, or 25v - same as above. 8)

User avatar
tekilap12
Information
Posts: 3
Joined: 27 Sep 2010, 19:37

Post by tekilap12 »

capitor 100nf?? dont see

User avatar
tekilap12
Information
Posts: 3
Joined: 27 Sep 2010, 19:37

Post by tekilap12 »

tekilap12 wrote:capitor 100nf?? dont see
C1 C2 C3 wher is " + " ??

AC128 how i nkow who is C, E, B ?

User avatar
Scruffie
Opamp Operator
Information
Posts: 1739
Joined: 13 Mar 2009, 17:59
Location: UK
Has thanked: 28 times
Been thanked: 170 times

Post by Scruffie »

tekilap12 wrote:capitor 100nf?? dont see, C1 C2 C3 wher is " + " ??
AC128 how i nkow who is C, E, B ?
Well spotted, I missed it off.

I've added the C&E for each transistor now, you would have had to have checked the schematic to find out.

If you look at C1,2,3 you'll notice that one side is slightly shaded, that's the negative :thumbsup

Updated Layout:
Attachments
Fuzz Factory On Board Pots Layout.gif

User avatar
azrael
Cap Cooler
Information
Posts: 564
Joined: 02 Jun 2009, 14:07
Has thanked: 35 times
Been thanked: 88 times

Post by azrael »

So, people who have built this pedal...Did you have to switch around sets of Germaniums to find ones that would work properly in the PNP negative ground position?

If so, I'm thinking about building it "upside down" with positive ground config, with a 2N3906, and a charge pump so I can run it with negative ground effects.

User avatar
ckyvick
Resistor Ronker
Information
Posts: 441
Joined: 21 Nov 2008, 06:53
Has thanked: 1 time
Been thanked: 4 times

Post by ckyvick »

^Why build it with npns and positive ground? the npn ges are usually more expensive :scratch:
Ive built a few with different pnp germaniums and honestly i couldnt tell much of a different with any set.

User avatar
Scruffie
Opamp Operator
Information
Posts: 1739
Joined: 13 Mar 2009, 17:59
Location: UK
Has thanked: 28 times
Been thanked: 170 times

Post by Scruffie »

azrael wrote:So, people who have built this pedal...Did you have to switch around sets of Germaniums to find ones that would work properly in the PNP negative ground position?

If so, I'm thinking about building it "upside down" with positive ground config, with a 2N3906, and a charge pump so I can run it with negative ground effects.
Well normally, converting PNP Germaniums to Negative Ground would cause all sorts of issues like oscillation, motorboating etc. But in this case... that sound is basically encouraged for the pedal, so you may aswell just use any Ge PNP, don't really need to find the 'right' ones to make it work.

User avatar
azrael
Cap Cooler
Information
Posts: 564
Joined: 02 Jun 2009, 14:07
Has thanked: 35 times
Been thanked: 88 times

Post by azrael »

^Huh, okay. That's interesting. I've tried the negative ground PNP transistor arrangement before, in a fuzz face using some Japanese transistors, and i was getting motorboating and oscillation, even at low gain settings.
Hoping to be able to replicate these settings I found...
Image
ckyvick wrote:^Why build it with npns and positive ground? the npn ges are usually more expensive :scratch:
Ive built a few with different pnp germaniums and honestly i couldnt tell much of a different with any set.
I dunno, just trying to think of a config that wouldn't cause any problems. Plus I have some NPNs.

User avatar
Hides-His-Eyes
Tube Twister
Information
Posts: 1940
Joined: 02 Feb 2010, 12:34
Has thanked: 50 times
Been thanked: 51 times

Post by Hides-His-Eyes »

azrael wrote:^Huh, okay. That's interesting. I've tried the negative ground PNP transistor arrangement before, in a fuzz face using some Japanese transistors, and i was getting motorboating and oscillation, even at low gain settings.
The fuzz factory is "designed" to oscillate and do weird things. Vex tries to use that as a selling point.

That said, running NPNs in positive ground will lead to all the issues that running PNPs in negative ground would.
Testing, testing, won too fwee

User avatar
ckyvick
Resistor Ronker
Information
Posts: 441
Joined: 21 Nov 2008, 06:53
Has thanked: 1 time
Been thanked: 4 times

Post by ckyvick »

azrael wrote:I dunno, just trying to think of a config that wouldn't cause any problems. Plus I have some NPNs.
The point of this circuit is to cause problems which makes the oscillations and crap noises that people want out of the pedal.
Honestly save your npns for a circuit where you could really use a nice negative ground fuzz. If you want this circuit to not make crap noises/sounds just make an npn mkii tonebender... Mindbender here:
http://fuzzcentral.ssguitar.com/mkII.php

User avatar
azrael
Cap Cooler
Information
Posts: 564
Joined: 02 Jun 2009, 14:07
Has thanked: 35 times
Been thanked: 88 times

Post by azrael »

Oh, I actually already build NPN Silicon MKIIs. :P Love that circuit! :horsey:

So the "crappy" method of PNP negative ground is actually WHY it's so different than a Tonebender, even though it's essentially the same idea (boost in front of Fuzz Face).

Gotcha!

User avatar
ckyvick
Resistor Ronker
Information
Posts: 441
Joined: 21 Nov 2008, 06:53
Has thanked: 1 time
Been thanked: 4 times

Post by ckyvick »

azrael wrote:So the "crappy" method of PNP negative ground is actually WHY it's so different than a Tonebender, even though it's essentially the same idea (boost in front of Fuzz Face).
Yeah, if you compare the two the factory uses the input boost as an npn si tonebender, then makes the fuzz face section pnp negative ground with a few mods/tweaks for added control over the squealing.

User avatar
RnFR
Old Solderhand
Information
Posts: 4879
Joined: 09 Jan 2008, 06:02
my favorite amplifier: Traynor YBA-III, Fender Super Six
Completed builds: custom fuzz.
Location: Inner Earth
Has thanked: 139 times
Been thanked: 133 times
Contact:

Post by RnFR »

it is possible to do the neg ground thing with pnp's. you just have to have the proper decoupling and layout. i do it all the time and it works fine. it's the lack of power rail decoupling that causes the oscillation in the fuzz factory, not necessarily the use of pnp's in a neg gr circuit. this kind of thing can cause motorboating at times, as some circuits are more prone than others(actually the tonebender is one of them) but that's not what's happening in the fuzz factory.
"You've converted me to Cubic thinking. Where do I sign up for the newsletter? I need to learn more about how I can break free from ONEism Death Math." - Soulsonic

Blog-APOCALYPSE AUDIO

Post Reply