ZVex Fuzz Factory

4 02 2008

Someone on a forum recently asked about a copy of the schematic for the ZVex Fuzz Factory. I had drawn up one last summer to contribute to the newly-christened Freestompboxes forum, but it contained a small mistake with the polarity of a capacitor and it was hosted on Photobucket, which has been really hard for me to work with. (Has anyone else out there had issues with Photobucket links not working correctly, etc…?)

So, without further adieu, I re-present the corrected schematic here, where it shall hopefully be easier for the seeker to discover.

ZVex Fuzz Factory
I redrew this schematic from a hard-to-read one which I found randomly on a Japanese site – possibly fffworks, I don’t remember exactly, and it’s been compared up against gutshot pics which can be found at, Effector Repair.
At any rate, successful builds have been accomplished with the previous version of this schematic (the one dated June ’07), and there is no reason to doubt the potency of this one. DIY layouts and exhaustive discussion of this circuit can be found at Freestompboxes.org in the “Boutique” section.

While you’re at it, I highly recommend checking out Effector-Repair for some really top-notch photos of various highly-prized effects… with complete disassembly instructions. I have the highest respect for the Japanese DIY scene, their Practitioners take an especial pride in quality work.



13 responses

27 02 2008

I really like how you draw your diagrams (e.g. https://solgrind.files.wordpress.com/2008/02/zvex-fuzzfactory-rev1-1.gif)

What software do you use?

27 02 2008

Hello, I use ExpressSCH. It’s a free schematic drawing program you can find here:

27 02 2008

Thanks Martin – I’ll give it a go.

15 03 2008

Martin, looking at the pictures from Effector Repair, shouldn’t two more of those 10mF caps be electrolytic/polar?

16 03 2008
Spencer Smith

I was curious if you could give me a parts list for the fuzz factory.

28 03 2008

Yes, I believe the 10µF input and output caps are polarized in the original, though it does not matter if you use bi-polar or non-polar caps in these positions. Personally, I prefer using non-polar caps for signal coupling.

Since many people have been asking questions about this circuit, I will do a “how-to” project with complete parts lists including vendors and a step-by-step of building it. I’m in the middle of moving right now, so please bear with me on this.


24 04 2008

Got a question:
What does the L at the pots mean? Is it logar.?


26 04 2008

The “L” stands for Linear Taper. I attempt to stay with the “L = Linear, A = Audio (Log)” standard for notating the taper of potentiometers.

8 05 2008

Thanks a LOT!

24 06 2008

The Schematic is so much different from http://www.beavisaudio.com/Projects/fuzzfactory.htm
and much simpler.
Wondering… which one is correct?

Ed. Note: The “Fuzz Factory” schematic found on Beavis’ site is an April Fool’s joke. It has nothing to do with the real circuit!

14 08 2008

I have built the fuzz factory twice now ,and in all fairness it has some interactive sounds,but they are just bias and voltage adjustments on the old 3 tranistor tonebender except the first transistor is inverted.flip the whole of the circuit,then flip the first transistor so it will be pnp, and you have the 3 transistor tonebender with varable resistors,its nothing new.

4 09 2008

Hi, i built this with a friend fuzz factory using this schematic and it worked perfectly. I tested it against a real Fuzz Factory and it was nearly identical. We made some changes to the schematic, we added a stereo input jack, and connected the negative of the battery to the ring. We also added a DPDT foot switch. The only problem we found was the connecting of the pots, we wired som of them backwards.

This is a great schematic.

24 09 2008

hey martin,
just wondering how the step by step instructions are going.
also im new to this stuff and i was wanting to know what kind of resistors to use (1watt, 1/4watt etc) and is that the same for all stompbox style circuits?

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: