Axis Face Silicon Debugging

[Kultur Vultur]

So I built an axis face silicon this today and for the life of me I can't figure out why it doesn't work. I get no sound at all when the effect is on, but bypass works. The only change I made was putting a 100 Ohm resistor between Q1's emitter and ground.

The schematic's here: http://fuzzcentral.ssguitar.com/axisface.php

Here are some voltages:

Battery: 9.28

Q1
C: 1.75
B: 0.70
E: 0.02

Q2
C: 4.55
B: 1.75
E: 1.06

10k Trim:
3: 7.85
2: 4.56
1: 4.56


Q1 has an hFE of 58 and Q2 has 128.


Any help would be appreciated. I can probe more points if it would be helpful.

[Dragonfly]

So I built an axis face silicon this today and for the life of me I can't figure out why it doesn't work. I get no sound at all when the effect is on, but bypass works.

I think you answered it right there.

Your voltages look ok, so....

1) you have a bad switch

or....

2) you wired the switch incorrectly (could be in the switch or the "to" and "from" of the board to the switch)

or....

3) theres a solder bridge connecting 2 lugs of your switch that shouldn't be there

I'd check those things first. Of course I usually have a bunch of extra switches around, so I usually just wire a new one in...usually fixes the issue.

[Kultur Vultur]

I fixed it, you were right about the switch. I didn't clip a wire end on one lug short enough and it was just barely touching a switch lug it wasn't supposed to. Wire cutters and a small piece of electrical tape (had to be damn sure!) fixed her right up.

This is my favorite fuzz ever! It's so perfect!


P.S. 2N2369A and 2N3903 transistors are fantastic.

P.P.S. Thanks a bunch. You folks are smart as hell.

[Dragonfly]

I fixed it, you were right about the switch. I didn't clip a wire end on one lug short enough and it was just barely touching a switch lug it wasn't supposed to. Wire cutters and a small piece of electrical tape (had to be damn sure!) fixed her right up.

This is my favorite fuzz ever! It's so perfect!

It's a good one, that's for sure !

P.S. 2N2369A and 2N3903 transistors are fantastic.

Glad you like the 2N3903's. Ever since I "discovered" them I've been "preaching" about them for use in fuzzes...just a really good sounding, easily obtainable low gain transistor....and the fact that they're cheap is good too ! 

P.P.S. Thanks a bunch. You folks are smart as hell.

RG is smart. Jack is smart. Mark is smart. Guys like them are the "big brains" around here. I'm just a guy who's learned (the hard way) from experience...

Enjoy the fuzz ! I'm glad you got it sorted out.

[kurtlives]

Kultur is this the same fuzz as the one you made the vero layut for a few weeks back? I remember you showing it to me.

[Kultur Vultur]

Yeah, it's the same thing Kurt. I changed the vero layout a bit so I'd have more room on the board for all the parts and I could use the more common C-B-E pinout for Q2.

If you want, I can post the new layout.

[kurtlives]

Ya please do.

[Kultur Vultur]

Here you go, kurt:



I used a 2N3903 for Q2 though.

[Branimir]

Congrats Kultur Vultur! I will try the 2N3903 too, I have used 2N2222 for both trannies around 130 and 140 both hfe's....

And yes Axis Face Si owns, I have done a two week european tour lately and it delivered great sound everyday without a single difference, no temp instability...

Greets from Croatia,

B.

[kurtlives]

Damn it Kultur...

I was going to place a little Small Bear order to get a few little things for this pedal and ending up spending $110.

This pedal better be awsome.

[Kultur Vultur]

Just don't forget to put a buffer of some kind in front of it. Fuzzes sound kind of bland without one. Too dark.

At least that's my experience. Maybe I have a "weak" guitar?


P.S. Thanks Branimir! Go for the 2N3903! ...And maybe a lower-gain transistor for Q1. It's worth it to pick "ideal" hFE values! Unless you're in love with your current tone. Then by all means keep doing your thing!

[kurtlives]

I got tons of transistors to try....NOS and all. I cant wait to try this fuzz out.

[Kultur Vultur]

NOS as in Ge?

[kurtlives]

Nah...I got a few NOS silicon mushroom caps. Vey nice in fuzzes.