Silicon Supa fuzz like circuit

[Ben Lyman]

Thanks Gus! It sounds better than it looks 

[Gus]

Anyone else build it?
A few people have tried my build and they do like it.

[Gus]

2017 bump a med power Si transistor version should be fun

[thermionix]

Dang that sounds good in Ben's video.  Gonna have to breadboard this one, pretty sure I have some 2N2222As.

[Cozybuilder]

Gus- somehow I missed this thread, glad you bumped it.

[Ben Lyman]

My brother still has this pedal, it's awesome. It's great all by itself just using guitar tone and volume controls for every tone you need

[Quackzed]

it really does sound good. i'm shifting my si tonebender build over into this version a bit at a time. i think i used a muffmaster as the first stage, then gained it down due to some squealing issues... not gonna shove that mess into this thread, just wanted to say nice work!

[thermionix]

I've got this on the breadboard, all 2N2222As with hFEs in the 240s.  My voltages are in line with Gus' original drawing, except my Q3C is at 6V instead of 8V.    My R9 is 4k7, should I go smaller there?  Or is it better to add some at Q3E?

[Gus]

thermionix what device did you use to measure the transistors?

What is Q2's collector voltage?

I made R11 0 ohms I found I did not need it
and reduced R10 to 330 ohms with an added .033uf across R10

[thermionix]

I measured the hFEs with my "RG Keen" tester that I built from his Fuzz Face article.  I don't really know how accurate it is, I see it more as a way to compare and match transistors, but it's presumably fairly close.

All of my voltages except for Q3C were just a tad below your original drawing, with my battery at 8.65V.

I ended up sticking a 2k7 in the R11 spot to get Q3C up to about 7.9V.  I didn't check yet what that did to the rest of the voltages, but surely some changed.

Now if I play a single note, it swells into an octave harmonic, before sputtering out fairly quickly.  Synthy attack overall.  Pretty cool sound, but I don't think it's right.

Think I should start tweaking other resistor values, or just try a different tranny for Q3?  Higher or lower hFE?

[thermionix]

Well I removed R11, and tried a variety of transistors in both Q3 and Q2 positions, hFEs ranging from 60 to 400+.  Nothing seems to make much difference to my Q3C voltage, only about +/- .05V.

That's not to say it doesn't sound good.  It sounds more "normal" this way than when I had a 2k7 in the R11 spot to get Q3C up, which made it a little gatey.  Can't really compare it to Ben's video; different guitar, different amp, cell phone vid vs. real life, etc.

Battery:  8.65

Q1c:  7.72
Q1b:  .659
Q1e:  .093

Q2c:  1.166
Q2b:  .540
Q2e:  0

Q3c:  5.95
Q3b:  1.166
Q3e:  .557

I used 4.7M for R1 instead of 10M.  Assuming that's just a pulldown it would probably need to be even lower to prevent switch pop, right?

I first tried 22n across the 330r like Ben, but switched that to 10n to preserve a more little treble.

I didn't bother with D1, R13, or C6 because it's just battery powered on the breadboard.

Everything else is per the schematic, at least as I understand it.  I used 220k for R6, and 4.7k for R9, isn't that correct?

[Quackzed]

i think r9 was adjusted according to the notes on the schem, you might try adjusting it to get rid of the mis-biased sound, after that i'd think maybee r6 could be lowered might try that..

[thermionix]

Actually it only sounded misbiased when I added the 2k7 at R11 to get the Q3C up to almost 8V.

Probably I'm paying too much attention to voltages and should just follow my ears instead.

[thermionix]

So I started transistor swapping, leaving the resistors how (I think) Gus has specified originally.

With those 2N2222As, all hFEs in the 240s, it's just a little too muddy to me.  So I tried some Amperex A115s with hFEs in the 60s and 70s.  Too low gain for sure.  Tried various 2+1 combinations of those two types, but nothing really grabbed me.

So I figured I need to try something in-between.  I have some 2SC1815Ys, out of a bag of maybe 20 I had only measured the hFEs of two at about 175 and 185.  Well I just grabbed three random unmeasured ones out of the bag, and they sound pretty good.  Might be on the right track with those.

Will mess with it more tomorrow.

[Gus]

My Q2 was about .85VDC and Ben's about 1.1VDC.
I used a 220K for Q2 collector
Try something higher in value maybe like a 270K for Q2 and measure the voltages again
If you reduce Q2 collector voltage you increase Q3 collector voltage

[Gus]

link

[Steben]

Sounds more tonebender circuit with silicon than silicon in a tone bender.
So yes. Once again. Circuit overrules mojo.