Zvex - Fuzz Factory

sonicolone · Post by **sonicolone** » 30 May 2009, 16:09

Hello. I decided to build my first DIY pedal as the fuzz factory and wired it up using radio shack 2n3906 transitors in place of the AC128s. I tried wiring it without a footswitch just to see if it would work and I get NO sound! Should these transistors work and if so, would would the wiring diagram be if I dont want to use a footswitch? Right now I have the positive input of of the 1/4 phono plug going into the "in" of the circuit board and the positive going from the "out" conection to the positive of another 1/4" mon plug, the grounds between the two are connected to each other and to the ground on the board - HELP!!

trad3mark · Post by **trad3mark** » 30 May 2009, 20:34

how exciting! i found some 60/40!! time to clean and try again!

trad3mark · Post by **trad3mark** » 30 May 2009, 20:36

sonicolone wrote:Hello. I decided to build my first DIY pedal as the fuzz factory and wired it up using radio shack 2n3906 transitors in place of the AC128s. I tried wiring it without a footswitch just to see if it would work and I get NO sound! Should these transistors work and if so, would would the wiring diagram be if I dont want to use a footswitch? Right now I have the positive input of of the 1/4 phono plug going into the "in" of the circuit board and the positive going from the "out" conection to the positive of another 1/4" mon plug, the grounds between the two are connected to each other and to the ground on the board - HELP!!

sounds like your jacks aren't grounded or anything...

Scruffie · Post by **Scruffie** » 31 May 2009, 02:44

sonicolone wrote:Hello. I decided to build my first DIY pedal as the fuzz factory and wired it up using radio shack 2n3906 transitors in place of the AC128s. I tried wiring it without a footswitch just to see if it would work and I get NO sound! Should these transistors work and if so, would would the wiring diagram be if I dont want to use a footswitch? Right now I have the positive input of of the 1/4 phono plug going into the "in" of the circuit board and the positive going from the "out" conection to the positive of another 1/4" mon plug, the grounds between the two are connected to each other and to the ground on the board - HELP!!

to the forum

A fuzz factory for a first build, it's a heavy undertaking, but you'll get there...

2N3906's are Fine (aslong as you orientated them correctly, did you socket them?) For a wiring diagram without a footswitch you should go here http://www.geofex.com/article_folders/w ... rapper.htm however in future if you can't afford a footswitch or just want to test a pedal I would suggest just a simple DPDT toggle or slide switch for testing, you can keep it pre wired to 2 Jacks and for true bypasss so you just have to put it onto the board when you want to use it...

Connecting Grounds between two jacks is fine, perhaps not the best practice, but it will work, check that site and check the datasheets for your transistors to check there orientation & tell us how it goes, if your still stumped putting up some good quality pictures is a great help to help others debug otherwise we have to do it blind.

Good luck!

RnFR · Post by **RnFR** » 31 May 2009, 03:04

how about testing it without the switch first? this is what i used to do before i started using my proto bread board setup for testing circuits prior to wiring. this kind of thing can make trouble shooting much easier. simplify everything as much as possible, then move on from there.

Scruffie · Post by **Scruffie** » 31 May 2009, 03:09

Yea that's what he said he's doing hence the geofex link to the wrappers sections which shows a pedal wired without a foot switch, the use of a toggle/slide was just a suggestion for future builds, I find it useful as I know it's wired correctly so I can't make a mistake with the wiring when I first test a circuit but completely omitting it is just as viable.

sonicolone · Post by **sonicolone** » 31 May 2009, 03:54

Guys, I took it in to an amp tech and he found to places where there was no continuity in a couple of my traces. Figures, as I traced the pcb board with a sharpie at midnight last night! Now its working and have to say it sounds pretty good with those 2n3906's. Thanks to all of you for the quick and helpful responses.

So now if I want to switch the transistors out for something better sounding what should I go for? Should it be a matched pair?? I am going to buy from Small Bear or a similar online retailer. How will 3AX31C transistors sound?? Any suggestions would be greatly appreciated!!

Scruffie · Post by **Scruffie** » 31 May 2009, 04:10

Aha problem solved!

If it ain't broke, don't fix it! If your happy with it's tone, magic mojo transistors aren't neccesarily gunna make it in some way better go for what sounds best to you however...

For better transistors...
Silicons I suggest BC558B's as my favourite as i've said about 200 times in this thread...

Germaniums if your going small bear just go for a PNP fuzz face set any will work fine really, this circuit isn't that picky in my opinion... although others may say differently.

If you hand pick Germaniums (not suggested for a first time build as you have to test for leakage etc) For a fuzz face (which this circuit is based off) you should use transistors in the 70-120 hFe gain band you can read about it here http://www.geofex.com/Article_Folders/ffselect.htm

And if you like both options of silicon & germanium it is possible to switch between transistors so you could have both silicon, both germanium or 1 silicon, 1 germanium, at the flick of a switch, which if you wan't i'l link you to the switching option.

Ozzie 88 · Post by **Ozzie 88** » 31 May 2009, 17:04

Wehey got mine working now! Started on a fresh board with sockets used and BAM job done!

First impressions GODDAMN this is a loud muthatrucker!

Although i do get a popping when i bypass it using that 'grounded input' method on a DPDT push/pull pot?

Now just to wire it up into my guitar!

SpencerPedals · Post by **SpencerPedals** » 31 May 2009, 18:09

All I really know about this thing is that it uses PNP and NPN transistors...is this one negative or positive ground? If it's negative and I can chain it with my others, it may get bumped up on the list of things to build.

sevinisthenumber · Post by **sevinisthenumber** » 01 Jun 2009, 23:32

Im building myself one of these and im wondering how you guys measure for your drilling? I want to copy pretty much exact zvex look

and im afraid im gonna space the pots wrong. How should i do this for it to look pro?

ShortScaleMike · Post by **ShortScaleMike** » 02 Jun 2009, 08:04

With a ruler?

Greg · Post by **Greg** » 02 Jun 2009, 08:12

ShortScaleMike wrote:With a ruler?

Pretty much..

I use a set of vernier calipers.. put some low tack masking tape on, and leave it there while you mark and drill to protect the paint.

ShortScaleMike · Post by **ShortScaleMike** » 02 Jun 2009, 08:46

Or make a drill guide on paper (draw around the lid of the case to get a template size), and masking tape that to the case before drilling.

I generally prefer to drill before sanding and finishing, as anyone can get unlucky with a paintchip.

soulsonic · Post by **soulsonic** » 02 Jun 2009, 08:54

I use a paper template, too. What I do is trace the perimeter of the box on a sheet of paper, and then use a compass and straightedge to lay out a grid. I follow the Rule of Fours when doing the grid, so I can place a hole at any point on the grid and it will have the proper proportion relative to any other point in the area. Then, I mark the spots on the box with a spring-loaded center punch.

Greg · Post by **Greg** » 02 Jun 2009, 08:55

ShortScaleMike wrote:
I generally prefer to drill before sanding and finishing, as anyone can get unlucky with a paintchip.

I'm too lazy to paint, so I buy powder coated boxes..

lynessmy · Post by **lynessmy** » 03 Jun 2009, 07:31

IIRC, i have seen a case earlier that the FF fail to oscilate....
I can't locate the tread with search function.

Is the problem being nail down? I have a case here where the FF fail to oscilate in a suddent.
Yes, ealier was ok but then it fail to oscilate anymore now.

My guess is one or more transistor had fail.
Mine to share your experience so that i can cut down the troubleshooting time?

Thanks ahead.

srguitar · Post by **srguitar** » 09 Jun 2009, 18:13

Hi guys

What gain values are suitable for a Fuzz Factory?

I've googled and googled to no avail. Do the two values need to be different? I have an idea about rough values (between 75 - 150?) but should one be around 80 and the other 140 or something?

are these ok?:
link

Thanks

trad3mark · Post by **trad3mark** » 10 Jun 2009, 16:45

yes they'll work fine. You could always get a bunch of different transistors, try them, and pick your favourite flavour.

Speaking of doing that, I've a bunch of random transistors here which i was going to try out this evening. Here's what i gots:
NPN
-----
2N3904
BC107
2N2222

PNP
-----
2N3906
BC558B
ZTX500

I assume i can just have a bunch of wires going to a breadboard and swap them around, right?

Scruffie · Post by **Scruffie** » 10 Jun 2009, 16:56

Yea you can, or the joy of sockets which would make life easier but that will work, don't break it again though please! lol.

I wouldn't worry too much about changing out the 2N3904 as it's mainly for the boost... the PNP's though.

Zvex - Fuzz Factory [traced]