bias? schmias!!

[pinkjimiphoton]

 

i lummoxed across something to use crummy, i mean REALLY crummy ge pnp's for. THIS WILL ONLY WORK WITH GERMANIUM. forget it with anything but.

the leakier, the better. low gain is fine. i built this with transistors reading 20hfe and it sounded better than GOOD transistors.
<shakes head>

the leakage from the transistors themselves makes 'em bias.

just twist the trimmers til it sounds good.

if you don't like using your guitar knob, remove r1 and r2 and just put in a 1m  pot, input to pin 1, pin 3 grounded, wiper to c1.

start with trimmers about half way up.

your guitar signal being present at the base will open the circuit up, so it's even kinda gated.

higher voltages lead to almost octave up, and very buzzy.
you can tailor the caps to wherever ya want.. bigger than this is fuzzier.

this is the stupidest, easiest thing i have ever built.

how does it sound?

to me, sounds kinda like ac/dc.

cleans up decent... but not fully .... via volume knob.

you can add a third stage... go from the out of the .47u cap to base of q3, ground e, connect c directly to b- for bizzarre synthy attack swelling gated fuzzy over the top ripping velcro goodness.  but to me, it was too much.

anyways... yah.... look ma, no bias resistors.

try it before ya freak out on me.

it sounds pretty freekin' good!!

transistors jansrc50's, hfe 20 and 24 on my meter.. didn't bother to test the leakage.



if ya wanna get real minimal.

all ya need is two trimmers, input coupling and output cap, two transistors and a volume pot.

8 part fuzz?

[pinkjimiphoton]

had a bit of a play with it today some more, this is what i think i'm gonna settle with.
it's a very "60's" sounding fuzz, cleans up fairly nice to a tubey crunch with the guitar rolled back some...
nice "incense and peppermints" kinda tone, a little synthy.

gain control makes it easier to dial in the sweet spot with humbuckers or single coils.

tone control could be put on a switch... with it ungrounded, this thing has hellacious high end bite. this mellows it out a little, and lets ya muffle it down some without losing balls.

played with a couple other values, and came up with the following. i realize the weird lack of bias thing may be an issue, at this point it isn't... i'm just trying to see whether or not a viable fuzz can be made out of this kinda of circuit, and it has a unique kinda "spitty" thing going on i'm kinda digging with a nice sustain.

if'n you're bored, check it out. it's a couple minutes on the breadboard.

i'll try and shoot some vid tomorrow... with my twin, i've decided the little hodad dealio is just plain too hard to tell what it sounds like in reality.
for some things it's good... for others... not so much.

anyways, apologize for the lame schematic, tried to lay it out so someon could make a pcb if they wanted to.

peace!

[deafbutpicky]

Hi Jim,
I played with something similiar recently. My Ts where not so leaky so I added a R from C to B and
got really nice sounds out of it but got a lot hiss (MP20 and GT108). got any tips? 

[pinkjimiphoton]

try starving the transistors more, or adding a smallish cap to ground from the output cap node.

should have plenty of output, i have this where it's reasonably quiet.

i'm still kinda playing with this a little... several variants... this one sounds decent on the breadboard into my twin.

you may wanna try some other transistors, too... some seem to be "hissier" than others. but if ya use trimmers for the c's, you should be able to dial in a nice sweet spot on each stage.. probably don't need to go as LOUD as you expect to get a nice tone. i found two stages like this to be a real nice combo!
three stages... not so much.

[pinkjimiphoton]

ok, dicked around with this some more today, thru various fenders to get a better idea of what it sounds like.

i like it.  different from my usual. can get a lot of sounds out of it, i really like how touch sensisitve it is, and how you can go from clean to scream with pick dynamics alone.

it's different. very 60's sounding. kinda cool.

here's a pcb/schematic of it. i gotta scan the hand drawn schematic and will try to up it tomorrow if i get a chance.



added an attack control (can ommit the 2.2u cap for a more normal "gain" control)

added a "contour" control

the diode clipper is also optional.

[boogietone]

Interesting. Will have to give it a go.

[pinkjimiphoton]

cool, yah it's a neat box... can get a lot out of it depending on how you set the knobs.

the attack and volume knobs are highly interactive, this thing is LOUD and should overdrive just about anything. for more fuzz, crank the attack and keep the volume low...
for more of an overdrive, keep the attack lower and the volume higher.
for octaves, crank both.

seriously thinking about adding the original booster to the end of this , cuz man, the pair sounds great together in a very earwig-chewing-thru-your-brain kinda way...

[pinkjimiphoton]

here's a vero.... haven't built it yet but all the nodes seem good

[Jdansti]

A little OT:  where's the best place to get Ge's?

[pinkjimiphoton]

i usually buy 'em off ebay, in lots.... but sometimes i'll find like surplus ones somewhere, like the ones i used in this. i'll have to try and find the website, it's been a while!!!

a lot of the russian ones i've tried work out fairly well. sometimes ya win, sometimes ya lose. that's why i'm experimenting with this, to find a circuit that likes crummy leaky low gain ge's.

i'd do a google search for them. sometimes, i'll just try and find something i hear about somewhere else.
odds are, if they're cheap enough i'll try 'em.

[duck_arse]

@jimi - can you wind it down to 3V supply and tell me how it sounds?

[pinkjimiphoton]

i can try, but i don't know if it will work. i tried it with a sag pot, and once it got to about 4 volts or so it pretty much crapped out.
i mean, it's just an experiment to see if something useful can be made with crummy parts.

i will mess with it a bit later and see if i can get it to fire, but i've aleady kinda moved on to some other projects.. stay tuned!!

[deafbutpicky]

try starving the transistors more, or adding a smallish cap to ground from the output cap node.

should have plenty of output, i have this where it's reasonably quiet.

i'm still kinda playing with this a little... several variants... this one sounds decent on the breadboard into my twin.

you may wanna try some other transistors, too... some seem to be "hissier" than others. but if ya use trimmers for the c's, you should be able to dial in a nice sweet spot on each stage.. probably don't need to go as LOUD as you expect to get a nice tone. i found two stages like this to be a real nice combo!
three stages... not so much.

Wow, you're a very busy man (or is it haunted by fuzzubus)
Further biasing on the C didn't do much noise wise. As I'm more after a breakup
than fuzz further highcut is too much, guess I'm out of luck with my (de-)selected
Ts.
I really like your idea of the attack control since I tried the SuzyQ (one more that has to be boxed up,
couldn't find a decent hippy pic yet...). Time for another studid pedal trick vid!

[pinkjimiphoton]

try starving the transistors more, or adding a smallish cap to ground from the output cap node.

should have plenty of output, i have this where it's reasonably quiet.

i'm still kinda playing with this a little... several variants... this one sounds decent on the breadboard into my twin.

you may wanna try some other transistors, too... some seem to be "hissier" than others. but if ya use trimmers for the c's, you should be able to dial in a nice sweet spot on each stage.. probably don't need to go as LOUD as you expect to get a nice tone. i found two stages like this to be a real nice combo!
three stages... not so much.

Wow, you're a very busy man (or is it haunted by fuzzubus)
Further biasing on the C didn't do much noise wise. As I'm more after a breakup
than fuzz further highcut is too much, guess I'm out of luck with my (de-)selected
Ts.
I really like your idea of the attack control since I tried the SuzyQ (one more that has to be boxed up,
couldn't find a decent hippy pic yet...). Time for another studid pedal trick vid!

yah DBP, my little booster is kinda hissy. this one isn't, but it's gotta SPITTY...not splatty necessaily... attack. it's cool, it's wicked touch sensitive, think about it... the more voltage you generate
from your attack the more volume it puts out the top. it's very very weird!!

if you try the contour control i put in this last variant, in the middle will be a nice bite... kinda muddy to the left, more muffled to the right and the sweet spot somewhere in the middle.

try putting a BFR from base of the offending q to ground maybe?

my little one stage booster has some hiss to it, but my noise gates pretty much eradicate it... it kinda adds some "air"..

did you try the old cap to ground trick off the output pot? try a small cap... maybe 47p between wiper and ground of the output  volume pot, you may be able to bleed the hiss to ground. you won't really start messing with the high end too much other than "air" til ya get over about .0047 or so to my ears, last i checked i could hear to about 12k or so. you may be able to smooth it just enough where you don't lose too much bite, remember you can add a small resistance to it too to form a simple filter. i often make temporary kinda tone controls with caps and say a 100k pot to find good combinations of r/c to roll off frequencies i wanna attenuate.

very much cookbook experimentation kinda zone here, so enter at your own risk.

[Jdansti]

Thanks for your help finding Ge's. Got Digi2t's PM.

[pinkjimiphoton]

you're welcome!!

[pinkjimiphoton]

stupid pedal trick... it works!! i really dig this thing...

and the vero above is verified!

[bluebunny]

A little OT:  where's the best place to get Ge's?

FWIW John, I got some GT404s off this guy in the Ukraine (eBay, of course).  They all seem to check out OK.  I'd happily go back and buy more.  "Best"?  Dunno.  But a happy bunny.  

@PJP: Indeed, I think I'll go back and pick up some PNPs for this build.

[Jdansti]

Thanks Marc!  I wonder what Jimi can do with one of those Geiger tubes the guy is selling.

[bluebunny]

I wonder what Jimi can do with one of those Geiger tubes the guy is selling.

"Photon Phallout Phuzz"?