schizoid face rev 4 (final)

[EBK]

Thanks, Jimi!  I'll keep that in mind when I get ready to build.

[EBK]

So, yesterday, this board assembled itself.  It borrowed my hands and my solder to do so.  Weird.


Apparently, these are the transistors it chose.


I have no clue if this will sound good or not.  I'm not a fuzz expert.

Self-assembly stopped at this point, so it looks like it is up to me to finish building it.  Interestingly, there is a 1K trimpot in the pile with this, so I guess that will be the fuzz control.  I won't question it at this point.

Edit: I have the drawing of the schematic and vero layout, which I can repost if Jimi says it is ok.

[bluebunny]

So, yesterday, this board assembled itself.

Given the 2¹/₂ years since the last update, I'd say it got bored waiting for you, Eric!   

[EBK]

So, yesterday, this board assembled itself.

Given the 2¹/₂ years since the last update, I'd say it got bored waiting for you, Eric!   

That's quite possible.  I can't even remember what I had for breakfast two days ago.  There's no way I'm remembering something I planned to build over two years ago with no evidence of having even started the project.  There was no printout in my collection of papers, no parts set aside specifically for this, no bookmark in my browser, and certainly no unidentified board sitting in my collection ala Mark Hammer (there was, however, a scrap of vero in my pile that was the exact size I needed, but it didn't have any existing trace cuts or anything else suggesting a predetermined purpose).  That's why I can't take credit for picking it up and building it.  Like I said, it is weird.    Fuzz gods at work?  I hope mine ends up sounding good. 

[pinkjimiphoton]

haha the fuzz gods smile, somewhere......


erik, i think you did a pcb layout for this for me, in fact





but i dunno if this was yours or not






















if ya poke around over on FSB, helmutt/aquataur just revisited this i think, and may have some interesting deets.

i think this should cover most of the project. the idea was for the led's to be eyes on a smiley/sad face... blue for sad, green for happy, red for bypass





the q's i spec'd are mpsa06, hfe is usually 140-250.  just use whatever ya got for low gain sili's, and put the lower gain one in q1.  you may have to play with the emitter resistors slightly if outside the 200hfe range... ya gotta 20% tolerance, easy.

hard to believe every one of these ended up sold. crazy. nice sounding fuzzface variant. the blue side is a sweeter ff that ended up as a commercial product, in fact. nope, not gonna say who ended up with the design, but there's some cool people using it... most of whom i've never even heard of, but appear to be selling some music. so i'm stoked

i can't seem to find the full gospel build doc with everything on one page, sorry. its been a few years since i even thought about this circuit.

so many fuzzes. my book of circuits has grown to two huge binders about a foot thick. now that i'm building for that company and doing their designs , i hardly ever have a chance for much experimentation, and they get uptite if i release anything to my diy brethren.

soon tho, i'll have the go-ahead to do that... anything i come up with they don't wanna sell will end up released. there's a BUNCH of stuff... the latest is a two transistor dealio using 2sk30a fets and a rotary 4 way switch... lets ya go treble booster, rangemaster, overdrive or fuzz with the one circuit. as always, its a stupid simple as i can make it.

one hint is just changing values of input cap can and will completely change the character of distortion circuits.

also, if ya go with a big enough box to accomodate 3 footswitches, i would make the output cap so it switches between the sides of the 8.2k bias resistor. why? well, at the "top" of the resistor, you got standard fuzz face pretty much... at the bottom, the node with q2 c, you get a substantial output boost that's bitchin' for leads. just a thought   the output cap will block dc either spot. if ya go with a 10-25k trimmer there, you can find a balance point between a decent bias, and output boost. like everything, its a bit of a compromise

and my last tip of the day... 4558? @#$% them things. 1458's sound better. more dynamic, like an op275, and far more amp-like response. the guv'nor himself used them in some of the finest sounding marshall products ever released, good enough for me.

i'm not even supposed to mention that chip lol the management would kill me for mentioning the "secret weapon" lol  but try one, my fav jellybean arachnid roach of all time.

anyways... nice to see someone messing with this again. hope ya have fun bro. if ya need me, or info, or any of the shit we all know ya don't already, invoke me and i will appear lol

peace out and happy solder fume sniffin'

[EBK]

erik, i think you did a pcb layout for this for me, in fact

Not me.  The last layout I designed was in November of 2000 (which is proudly emblazoned in the copper layer of the board, a Crybaby Wah, still sitting in my unfinished pile).

the q's i spec'd are mpsa06, hfe is usually 140-250.  just use whatever ya got for low gain sili's, and put the lower gain one in q1.  you may have to play with the emitter resistors slightly if outside the 200hfe range... ya gotta 20% tolerance, easy.

The transistors that chose themselves measure 209 and 237.  I guess they'll work ok.  We'll see.  They are socketed.

[Mark Hammer]

Somehow it seems poetic and fitting that all the pictures posted from 2017 are...well....fuzzy. 

[pinkjimiphoton]

Somehow it seems poetic and fitting that all the pictures posted from 2017 are...well....fuzzy. 

everything about me is fuzzy, mark! lol

here's the most recent photographic evidence of how fuzzy the old hippy has gotten

https://www.youtube.com/watch?v=WVpbXG83sJI

me n my latest protege, eli who sat in the last show with my power trio... 18 years old, kid kills it

weirdly, no fuzz involved... well, with me. he's using one of my fuzzface + pedals, me? les paul into marshall. my fx is a straight cord

taken last friday at the local MC's clubhouse

guitar wankage

[EBK]

This still technically needs a diode or two in the power supply subcircuit, but I might skip them to give it a listen.  I have a bunch of other transistors I might audition with this as well.



Update:  My kids are asleep, so I gave this a quick low volume test to see if it fires up and fuzzes.  It does!  Will have to give it a real listen tomorrow.

[pinkjimiphoton]

went with a trimmer for the gain? i should do that more, but for some reason i still like knobs. let me know your thoughts once ya destroy them cillia in your ears a while.
this, or very nearly this, is actually now a commercial circuit believe it or not.

[EBK]

went with a trimmer for the gain? i should do that more, but for some reason i still like knobs.

Yeah, I don't have any lowish value pots on hand that aren't trimmers, and I had vaguely recalled you endorsing a fuzz-at-max-always philosophy in one of your videos, perhaps even for this very circuit, so I went with it.  Thought the idea of a one-knob or no-knob fuzz sounded pretty daring too (I'm sure they exist), so this will give me a chance to more or less test that out.

[pinkjimiphoton]

yeah, really, i mean... how often does anyone leave the fuzz knob below 11?? lol

[EBK]

An initial report:
I have only been able to test this circuit through headphones so far, so it is not a true evaluation of its potential, but here are my observations so far.  Tested with single coil vintage pickups (Fender CS69) in parallel and in series.

With the transistors that landed in the sockets, it definitely fuzzes, but sounds VERY dull and somewhat muted (the fuzz doesn't ever cut out or splatter, but noticeably downshifts quickly) until that fuzz control is cranked WAY up, then it blooms quite nicely. 

In the more trebly mode (I forget which one that is) it is extremely noisy but nicely searing and crisp.  Makes me feel like ripping through some raw lead solos. 

In the other mode, it makes me feel more like chugging some power chords.  Less adventurous, but reliable feeling. 

I feel like I definitely need to try some other transistors.  Should I look at anything other than the gain measurements when picking them?

[pinkjimiphoton]

description sounds right. throw it into a tube amp or an overdrive and it should warm up nicely.
hfe on the original run was about 215, lately i've been using around 150hfe for q1 and 180 for q2.
its been so long i really don't remember... i do remember there was a bluesy-er mode and a more biting one, but... been a while, ya know? lol

[EBK]

Swapped out the previous transistors for some ECG123A ones with gains of 143 and 165.  MUCH improved. Sounds useful over a wide range of the fuzz control. More testing needed. Gotta go.   

Edit:
For no special reason, here is an updated pic.  I love the way these transistors look (small and very shiny).

[pinkjimiphoton]

i suspect the ratio of gain is important. but that said, lower gain will def work better i'd imagine.  for higher gain, try doubling the e resistors etc. there's math involved. i went to windham public schools. 'nuff said. hence the 10,000 monkeys approach i take so religiously