yaf..... the double hit deux

[pinkjimiphoton]

thanks jack!!!
i did try messing with it last nite, i may have messed it up tho as i have the grounds for all the pots going to the star ground on the input jack.
i tried rewiring it so pin4 of the two chips was fed the 4.5v from the junction of the divider and 33uF cap, but it wouldn't fire at all... i'm assuming thats cuz the grounds for the fuzz and octave pots weren't going to the half voltage maybe?
i DO have another board, so i'll try building it up as suggested... easier to do now than it is on what i have so far.
i will try n shoot a bit more video of it as it stands now... i switched to a different q, something from the 2sc series, i can't remember which (had to twist a couple legs) but it brought the fuzz to life. the octave side i think i have ok now, the noise issues i had i believe were from subsonic noise getting frequency shifted up a bit... changed the 1uF coupling cap from the input stage to 47n, attenuating the lows really made a difference. the whole thing is now a decent amount above unity gain, but the octave part is still kinda low in comparison to the fuzz part.

it actually sounds a bit better than it did in the video posted yesterday... still crackin' at this nut, may take a while, but in the end it should go good on a pizza with bacon and pineapple.

as they say... stay tuned!!

and thanks for the help/advice!! you rock bro!

peace

[pinkjimiphoton]

where its at at this point. i had mistaken something somehow, it runs fine on 9 volts nothing spooky or mysterious but the cobwebs in the foggy abcesses of my mind....

this works. runs on 9 volts, sounds pretty good. i haven't added the caps in series with the fuzz and octave outs yet, but i think i should cuz i get a little interaction between pots sometimes that manifests in a little scratchiness during the end of the pots rotation.

'nother vid soon. gig tonite.

check it out

[pinkjimiphoton]

took it out last nite to try it thru my stage rig and the other guy's amps.
in tubes, it sounds great.
in solid state, YECH. NOT READY YET!!
so i plan on adding a bit of low pass filtering, its got some high squeaky parasitics happening with the line 6 i tried it thru... frequency doublers don't help lol

so a cap and resistor to ground to bleed off some of this ultra highs will work i think.

questions:

do ya think caps alone will be enough to isolate the mixer parts from each other?
there's a bit of crosstalk and i think some dc getting thru with the pots when some of them are maxxed.
i was thinking .47 for the fuzz side and .0047 for the octave side... but will they then interact with the "output" cap?  i mean, caps in series act like resistors in parallel, so will this mean i will get the "average" of each pair of caps as an output cap?

is there a preferred <read: simple> way to decrease treble content, i'm thinking resistor and cap to ground to make a simple low pass filter to shelve off the parasitics... looking at the circuit, i'm thinking the two optimal places to do this would be either just after the voltage divider on the input stage, or at the junction of the 47n/10k input to the + input of u1... or is there a place ya think may work better?

slowly closing in on making this thing useful/useable. determined to turn its suck knob to a shine one!

[pinkjimiphoton]

some pron

[amz-fx]

Try connecting the 10k on pin 3 of the first op amp to the 4.5v bias instead of to ground.

regards, Jack

[pinkjimiphoton]

i can most definitely try that. there's nothing actually hooked up to that 4.5 volt node!!

BUT if i disconnect it, the circuit gets very unstable and the fuzz sounds horrible.

i will try hooking it up there tonite when i get a chance and see what shakes out. thanks jack!!

[pinkjimiphoton]

hey jack,
if yer still out there campin'
i tried hooking up pin 3 to the half voltage. no dice.  i was looking at it when i realized the damn circuit as i had drawn it was wrong, and basically the top of the 10ks in the voltage divider was actually broken off down by the cap.
so i took it apart, and it still makes no sense at all. i drew it up carefully, and this is exactly what's on there, i can't make sense of it still, tho i seem to remember seeing something kinda similar once in an old kay 70x amp, where they used some caps in some pretty peculiar ways.

for all intents, the anode of the 33u <now 47u> was connected to b+. the bottom of the cap, the cathode, was connected directly to "ground" but also had a 10k resistor between the bottom of the cap and ground. if i disconnect this stuff, the circuit will run, but is wicked unstable. to me? this makes no sense... a cap to ground should read 0 v, but with the 10k resistor in parallel with the negative lead, i'm getting a little over 2 volts at that node!!

still playing with it... sadly, lost the freaky abilities it had in the video <can always mess up another one, i actually kept notes for a change> but it sounds a LOT better.
i added blocking caps to the outputs of the fuzz and octave... not a huge improvement as expected, but a bit less crosstalk when mixing the levels.
bringing down the 10 k to the - of u1 to 1k made a big difference... now i seem to have a decent amount of fuzz, treble, and sustain. so i gonna try it on the input of the other oa as well. i may go up in value a little bit, i think the sweet spot is around 2.5k.... we'll see

gonna try going to 1k with a 10k trim on the diodes in the octave part rather than having the 10k's and a 10k trimmer betwixt them. we'll see what happens.

i MAY try adding a simple boost/bazz fuss stage to the begining. or i may just do a p2p fuzzface. this thing sounds great with a fuzzface up front!

so up to rev 4. its getting a LOT closer to useable! stay tuned!

[pinkjimiphoton]

yeah....
it sounds cool now. BUT i figured out a couple issues, one of which is like, WAY too much dc on the output from the fuzz.. 2.4 something volts, seems excessive but i dunno.. it drives the amp pretty good, and has a nice raunchy overdrive to it.

but here's i think where things get weird.
there's that whole half voltage thing.
apparently some things CAN connect to that instead of ground, but SOME things MUST be earth grounded? 

remember, i am an idiot. a 10 toed freak of a monkey with a breadboard and an occasional altitude problem.

anyways, unless yer brave or insane, better leave this one to me til i sort this out. i believe the ground is somehow not what it appears to be... and i think the pots need to be grounded to the chassis better somehow, they connect to the star ground on the input jack.

i just don't expect to see almost three volts signal on the output of a fuzzbox with no signal passing thru it

its almost like the whole thing is floating off that one freaking resistor coming off the  - of the 33u cap (now 47u)...

i figured out the audio was leaking thru the cap charging off the positive rail and then discharging, which was giving me that way cool envelope sound in the video the other day, and i figured out the resistor in parallel with the - of the cap  ws controlling the envelope time. i think in some way it was like ring modulating the signal with pollution on the ground rail  or something. i have some kinda weird feedback loop thing going with it i need to figure out. it SOUNDS cool, but that kinda output seems like it should be worrysome.

so anyways, pretty much everything is actually "grounded" to that 2.13v spot at the node of the - cap and resistor to ground seen below. with the present 47uF cap and 27k resistor, its hanging at about 3.19 volts or so. the batterys kinda drained, so i expect it will go up a bit when i put it to a power supply.





this is where i think i got it @#$%ed up. it works, but like i said, its gotta lotta juice on the output, even after adding blocking caps, cuz the "ground" is actually somehow more like a negative rail, i am definitely not understanding this one at all at all.

all the stuff circled i assumed went to "ground" actually goes, somehow, to that 3.xx volt tap on the power supply.

the chassis appears to be grounded, but now thinking about it i better check from the neg of the power jack to ground to see if there's voltage. i bet its 3.19volts.

so unless i'm completley off base and out of my mind, this thing should probably be shelved, yes? just from a safety viewpoint?

seriously, is this thing gonna destroy my amp?


if i try to hook it up "normal" nothing works. wtfff

[pinkjimiphoton]

most recent variation. nod to Jack Orman from amz, i stole his muffer circuit pretty much and used it for the front end... doubled up on the diodes and slightly different values.. but this part of the circuit sounds like a good fuzz now. thanks bro!!

but MAN! we got issues... shit shouldn't even be able to work i would think at all!!!!

this is what i have at the moment. every triangle with a circle is reading that impossible 3 volt supply off the bottom of that freakin 47u cap.
pin 4 of both chips reads 0v. that i expect. but all the other places that should be "ground" read 3 volts. something weird going on i just can't seem to figure out!




be back with voltages later. they haven't really changed, other than bumping the 2.13v up to 3.20 or so.

it SOUNDS great, but "ground" is reading 3.20 volts, and i have 2.4volts dc hitting the output jack when this thing is engaged with no signal going into it. something wrong!!

how in hell can a shorted resistor be reading any voltage?
this is what i got powering it





if i remove the 2.7k resistor, or the cap, or lift the grounded part of the cap from earth, the whole thing stops working.

how can this possibly be?

[pinkjimiphoton]

i gotta redraw the schematic, and button up a couple weird details,... but... its alive

i am such a dumbfugginidyot!!

so like, i been messing with this and messing with it, going batshit crazy trying to figure out what's wrong, right?

@#$% @#$% @#$% @#$%ity @#$% me!

i had the pots all on the same ground bus
and had that grounded to the "ground" on the board
which was actually that couple volts offset on the low side of that cap.

once i disconnected it and reconnected it to the star ground on the input jack, the fuzz was back in business, and better than it was cuz no more freekin dc.

i gotta do some more stuff to it, but thats what i did. i had insulation over it and didn't even realize what i did one of them bleary eyed 3am "time to solder" after a nite rabble rousing at the local pub n snout. nice.

so so far, all's well. the power supply is still wack, but it works, sounds good, and no dc. i'll take it as a win.


oh....
and i was thinking... just something to ponder...

if a simple wire link is considered to be one ohm for all intents in some circuits

having that cap hooked up like that... i THImK... may work like this...

two resistances in parallel... 27k, and 1r...
well in math, anything divided by 1 is itself, right?
so 27000 divided by 1 = 27000, right?

so it can't be a short in this case, even tho it SHOULD be, right?

the - side of the cap is usually the outer foil shield.. if ya use electros for coupling caps, and touch the top of them, sometimes they'll buzz or hum cuz the shielding on the outside isn't connected to ground. but the shielding IS connected to the - lead of the cap.

so effectively, we're grounding the shield of the cap, and floating it above the negative rail with the 27000 ohm resistor in parallel with the 1 ohm one.  the one ohm one, of course, being the negative lead of the cap, connected to the shielding of the cap and grounding it for less noise.
27k divided by 1 is still 27k, right?
as above, so below?
trickle down... oh, never mind...


its the only way i can see this working, and it IS working and SHOULDN't be...

does that make any sense at all?
i DO remember seeing this done at black cat on their vibes to keep hum and noise down.. i was like... weird.. in that case, they had ground straps to the shields of some of the caps or something like that.


this may be a similar application, and man, i'd love folks thoughts on that one.

anyways, i'll post the final last weird little tweaks to it tomorrow or tuesday, after a week of being an idiot looking at this thing i need a nights sleep

[radio]

https://www.diystompboxes.com/pedals/FAQ.html

Under Vref

[pinkjimiphoton]

yeah, i know, but that does not work in this, lol.

i tried extensive variations of power supplies, the only other way to get it to fire was to run two 100u caps with their cathodes tied together to ground, + or 1 to 9v, + of the other to -9v. it STILL needed the leak resistor to ground to function.

it will pass audio with a voltage divider, but it won't fuzz.

i been on this thing like white on rice for days trying to suss out how it could work, the math doesn't lie...  27000 divided by 1 is always gonna be 27000 bro

and its the only way this thing will fire... it WANTS a bipolar 9v supply, 9v + and 9v- with
"ground" in the middle

if it looks like a duck, and it quacks like a duck....

it can't be an aardvark, right? 

[pinkjimiphoton]

ok, that last feverish thought couldn't work. parallel resistances don't work like dividing numbers. even if they did, it couldn't work right.

still scratching my head, but think i figured it out. i was mistaking what would actually by vcc for ground.

from another post:
pinky don' be knowin bouts no ones or twos or kemzars of resistance

still trying to wrap my mind around how the heck this thing is working.

the negative lead of the cap is most definitely going to the ground plane, "between" pos and neg. this plain reads around 3 volts now.
the positive side of the cap <now 100u> goes to the b+
the negative side goes to the "half" voltage ground plane between the two power rails
a resistor comes off that mid point on the cathode/ground side of the cap and goes to the actual -9v ground coming from the star ground.
at the junction of the resistor and cap cathode, is the 3 volt voltage. its not "ground" its something floating between the rails. i think.

so we got -9v, or ground
we got /+9v or vb
and we got "virtual ground" which is offset from "actual ground <-9 v>" by about 3 volts... close to half voltage.

before the star ground connected -9 v/ground to the board.
i had mistakenly thought the mid voltage was ground, not a mid voltage... hey, everything "grounded" to it, right?

but everything SHOULDN't have .... when i moved the ground point for the three volume pots to the input jack star ground instead of where it had been, it worked. when investigating that, i found that a little blob of solder on the second part of the fuzz/oct footswitch was actually shorting to the ground lead for the led's... thats what was letting the dc into the output signal.. again, my bad and a cheap mistake

so in reality, -9v is ground. +9v is vb. the mid point, leaking off between ground and the cathode of that cap is where the 3v is coming from. its gotta be.

sorry, just trying to wrap my head around what was making this thing tick... now it sounds pretty good, and seems to be working. i'll take that as a win, and hopefully get some video of it soon too.

so, does that make sense? i think me mistaking the midpoint for ground is what @#$%ed me up.

of course, the bloody @#$%ing ground IS connected directly to this midpoint as well, by a jumper, still makes no sense... but... hey...

lol
i need a week on a mountaintop with some mycelia-ey goodness methinks 

does this explanation work somehow maybe? only other thing my fwacktured widdle bwain can come up with....

[pinkjimiphoton]

ok, i see what i did wrong, and why i was pulling my hair out.
this i believe is it, and works really well like this. its weird, but it works!
i had definitely confused ground with the vcc "half-ish" voltage
on the board, they are actually jumpered together... i thought. turned out that jumper was just for pin 4 of the opamps. go figure. i apologize for so much wasted bandwidth on my stupidity. but maybe it will help some other moron like me some day. probably my OWN moronic ass, even.

anyways.. drawing rev 6, should be the charm, works great and sounds pretty good!!

[pinkjimiphoton]

in the end, the last schematic is good, other than choosing a .33u cap for the input cap.
its still a little gated, but its not too bad... compared to what it WAS, a lot better.

i think so, anyways... but, hey!! wtf do i know!!!!

here ya go... styuuuuuuuuuupid pedal trick for the double hit deux, part deux

the smell of #fuzzygoodness

https://www.youtube.com/watch?v=M57uD8vKA6M&feature=youtu.be

usual les paul variant into my princeton, kick on a SSOD and a bit of echo here and there.. but ya should be able to get a good idea of how it sounds.  rock on! stay fuzzy!

[pinkjimiphoton]

never able to leave well enough alone, i did some changes again.
5089 for q1
ne5532 for u1
ca3140 for u2
made the rectifier part diode clippers for each side, 1 ge diode feeding one ge diode clipper x2
increased the coupling cap to the second stage to 4.7u
now the octave and fuzz are much closer in volume.
may still play with it a little bit tho... never done. you know how it is

[jopyeweed]

Hey PinkJimiPhoton,

I know this is an old thread but I am working on the same Graymark Double Fuzz kit you posted about. I have it all together and I dig it but the one problem is the fuzz side is too quiet. I was wondering if you came across a fix for this? I went through the thread but it gets pretty hairy. It seems like there is a clean signal mixed much louder in with the fuzz. I can hear the clean coming through the fuzz, sort of. Otherwise I'm fine with the two battery situation but I get where you're coming from with the sustain/gating decay problem. Did you ever settle on a good fix for that? Hope you are well and I enjoyed the thread and your video. Any new vids or audio of the pedal as it ended up?

Thanks,

_Shawn