smallsound/bigsound Team Awesome! Fuzz Machine  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
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frooshontay
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Post by frooshontay »

So I found these pictures on the ss/bs blog, located here: http://smallsoundbigsound.blogspot.com/ ... -work.html

The pictures should give someone a good start, and the other image should give all of the part values. I'm not sure what the changes were between versions. I tried my hand at figuring this out, but didn't make it too far. I figure I'll leave it to someone more experienced. There are some more pictures on the blog that I haven't attached.
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image.jpg
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skywise
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Post by skywise »

You could probably ask Brian some details about the circuit. He seems like the kind of guy that would be down to share. He's an actual DIY guy, not a razzle-dazzle boutique douche. :thumbsup

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smallsnd/bigsnd
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Post by smallsnd/bigsnd »

yeah that version is OLD! i think the newer one is better, but some folks' opinions differ with mine.
the details are pretty simple - split the signal, fuzz one side, mix them together - there are endless variations on the theme. :hug:

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Bill_Mountain
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Post by Bill_Mountain »

smallsnd/bigsnd wrote:yeah that version is OLD! i think the newer one is better, but some folks' opinions differ with mine.
the details are pretty simple - split the signal, fuzz one side, mix them together - there are endless variations on the theme. :hug:
The endless variations is what gets me. Every time I think I've designed the ultimate fuzz (for me), I start going, "...well what if I do this? What about this? Maybe I can use some boutiquey mod's here? Maybe I can replace this BJT with an FET..."

How did you get to the end and say, "I'm finished!"

Honestly I don't think I ever will.

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Post by smallsnd/bigsnd »

Bill_Mountain wrote:
The endless variations is what gets me. Every time I think I've designed the ultimate fuzz (for me), I start going, "...well what if I do this? What about this? Maybe I can use some boutiquey mod's here? Maybe I can replace this BJT with an FET..."

How did you get to the end and say, "I'm finished!"

Honestly I don't think I ever will.
that's quite the philosophical query. i usually go with my instincts and personal taste though i've been through roughly 6-7 revisions with the TAFM (subtle tweaks), so i guess i will never be finished either...

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skywise
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Post by skywise »

Bill_Mountain wrote:How did you get to the end and say, "I'm finished!"
There is really no such thing as a "finished product". You just run out of time and have to ship it. :thumbsup

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MoonWatcher
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Post by MoonWatcher »

I like that the attention has been put on a clean layout as opposed to having some kind of fancy capacitors on there. Just regular electrolytics and a few types of ceramics if I'm seeing things right.

I know it could be argued that with fuzz you don't need "audiophile grade" caps, but just the same - it's cool to see.

I'm sick of seeing stuff with Panasonic metalized film caps, or even the old school approach of cramming some monster Mallory 150 high voltage type axial caps just for the el-bling-o factor.

I got to work on a few 1st gen 90's Marshall pedals for a friend, and I overall liked the emphasis on layout vs. "premium component" choices. The pcb's shown in this thread remind me of them.

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smallsnd/bigsnd
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Post by smallsnd/bigsnd »

MoonWatcher wrote:I like that the attention has been put on a clean layout as opposed to having some kind of fancy capacitors on there. Just regular electrolytics and a few types of ceramics if I'm seeing things right. I overall liked the emphasis on layout vs. "premium component" choices. The pcb's shown in this thread remind me of them.
thanks! that's pretty much where i'm at. :thumbsup

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Post by nr372 »

I've got a more recent version of this pedal. The PCBs are marked "v6.2 2012". It's quite different to the boards posted above.

I went ahead and attempted a trace of it. The IO board is a nice little design; it's a Brass Master descendant with some added spice.

I'm pretty confident in what I've drawn, but I welcome any questions or corrections!

Important note: most of the capacitor values are different from what's marked on the PCB silkscreens. It makes me question the pot values a little.
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TAFM_IO_TRACE1.gif
TAFM_FUZZ_TRACE1.gif
TAFM_GUTS3.jpg
TAFM_GUTS2.jpg
TAFM_GUTS1.jpg

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Post by smallsnd/bigsnd »

pretty close for the most part. think brassmaster + tweaked fuzzface with tone control.

this was from an NPN revision and i've since gone back to using PNP with an LT1054 due to the very inconsistent nature of NPN germaniums. too much of a headache.

also, small tweaks since that version which gave slightly wider range to the gain and tone control. tiny resistor/cap tweaks which could be adjusted for taste for anyone seeking to build. pot values are generally 100K/gain, 10kA/clean, 10kA/wet, 5kC/fuzz, 25k/shape.

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Post by johnk »

i own the original SS/BS PNP version (that also has two internal trimpots) and built the NPN version posted here. it works and sounds great, but the gate doesn't work like the original. it does affect the nature and sound of the fuzz but it doesn't gate. any ideas about that?

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nr372
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Post by nr372 »

I looked over the connections to the Gate switch again, and the schematic above still seems right...But now I'm doubting myself.

Try checking the transistor voltages on the fuzz board. Here are the readings from my unit:

All controls at minimum, pedal bypassed, Gate switch OFF:
Q1: C = 0.31V B = 0.10V E = 0V
Q2: C = 7.92V B = 0.31V E = 0.25V

All controls at minimum, pedal bypassed, Gate switch ON:
Q1: C = 0.16V B = 0.05V E = 0V
Q2: C = 0.07V B = 0.16V E = 0V

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johnk
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Post by johnk »

don't doubt yourself. it works perfectly now.
here it is completed:
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TAFM-01.jpg

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nr372
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Post by nr372 »

That's an excellent looking pedal! Glad to hear it's working.

Quick question:
What diodes did you use? I still haven't been able to discern the part numbers on my unit.

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Post by johnk »

i measured the forward voltage on my (PNP version) original and they measured .235V so i used BAT41's that also measure .235V.

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Post by smallsnd/bigsnd »

johnk wrote:i own the original SS/BS PNP version (that also has two internal trimpots) and built the NPN version posted here. it works and sounds great, but the gate doesn't work like the original. it does affect the nature and sound of the fuzz but it doesn't gate. any ideas about that?
did you get it going? those NPNs can be a bitch and the gate control works inconsistently - some values may need to be tweaked to get it working properly.

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johnk
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Post by johnk »

smallsnd/bigsnd wrote:
johnk wrote:i own the original SS/BS PNP version (that also has two internal trimpots) and built the NPN version posted here. it works and sounds great, but the gate doesn't work like the original. it does affect the nature and sound of the fuzz but it doesn't gate. any ideas about that?
did you get it going? those NPNs can be a bitch and the gate control works inconsistently - some values may need to be tweaked to get it working properly.
yep. i socketed them so i just tried a different pair of germs and it works perfectly and sounds awesome! thanks!
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TWO-TAFM-01.jpg
TAFM-02.jpg

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Post by smallsnd/bigsnd »

top notch! :horsey:

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Addy Bart
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Post by Addy Bart »

This might be a silly question, but what does the internal dip switch do?

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Post by jrfox92 »

Addy Bart wrote:This might be a silly question, but what does the internal dip switch do?
Adds/removes a Jfet-based input buffer.

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