been a while, thought i'd post something new...

[pinkjimiphoton]

guys, what i described is what i built, and yes, it definitely works. instead of arguing with me about how it can't work, @#$%in try it

in the pic, as i described, looking from the back of the pot (not the shaft) with the lugs facing right, top being 3 , wiper being 2, and the last one being 1, the 3.9k resistor is between wiper and pin 3. pin one is NOT CONNECTED to anything. the cap is connected to pin 3 of the snarl control on one side, and to ground on the other. it comes off the bottom of the pcb (red wire in the second pic) from the node where the baalz pot input (pin 3 again) connects to the circuit board. it is in parallel with the baalz pot.

you guys are thinking potentiometer. it's being used as a rheostat, not a potentiometer.  i'm not shunting signal to ground via a ground connection on a potentiometer, i'm faking varying the size of a cap connected to ground by putting a variable resistance in parallel with the "input" of the cap.

Maybe everyone's confused because

THERE'S NO CONNECTION TO GROUND FOR THE SNARL POT ON THE SCHEMATICS

It's just a 3.9K in parallel with a pot, and the only connection for EITHER is the emitter. As drawn, neither component can possibly do anything. Jimi said he connected the cap to the back of the pot, so the pot's lugs must be connected to the back of the pot as well.

As long as lug 2 is connected to ground, then it will work exactly as you describe.

nope. it ain't connected to ground. checked it with the meter even. it's in the video. that said, lug two DOES connect to ground, sorta. it connects to ground  via the cap.
it's something to do with that 3.9k resistor tieing the wiper and input together. the cap would work if it were from the wiper to ground, yes?

well, the wiper does connect to ground.... cuz it's in parallel (like tieing an unused lug on a trimmer to the wiper so if the pot fails there's a resistance still?) with the input of the pot.

how about an experiment.... take a 50k pot, tie a 3.9k resistor from input to wiper, and check with a meter to see what the resistance changes are as ya sweep the pot. it will change. as you sweep it.... if it didn't. tapering resistors could not work.

so... if the pot is working... take some audio and put it to the top of the pot (lug three). leave lug one disconnected.

obviously, no effect on the audio signal. its just "hanging there" being an antennae.

but... add the cap to ground and watch what happens. you can add the cap to ground either to the input or the wiper.... pin two or three...  and it will work either way cuz of the resistor tieing 3 and 2 together.
originally i used the cap to ground from lug 2. it was too harsh. running the cap from lug 3 was much milder, and not as harsh....very subtle as opposed to very blatant. it won't/can't work without the resistor. take the resistor out, and ya have a cap to ground and the pot does nothing. put the resistor in, and suddenly it's connecting the cap to the input and the wiper. when ya sweep the pot, you can hear the "notch" where the signal cancels somewhat... but it's brighter on each end...slightly... than in the middle.
i used a continuity test in the video ya'll can see in the beginning. i have no connection to ground from pin one. i did it so ya'll could SEE and HEAR it, like i was right in front of ya. no beep, no numbers on the meter, no connection.

jon is close... "if pin 2 is connected to ground, it would work exactly as described"... well, pin 2 IS connected to ground via the resistor and cap. the insidey parts of the pot are in parallel with the resistor. sweeping the pot changes the resistance in total. the cap is always connected to ground.  the size of the resistance  is the only thing changing. it's like shroedinger's cat...  you can think of that cap being connected simultaneously to input of the pot and the output... if it's connected to the output, it obviously has to have resistance of the pot before it.... creates a filter. the resistor is also part of the filter, and is bleeding  electrons thru it, thereby connecting the cap to input and output of the pot.

i WILL open it up again later, and see if pin 2 or 3 connect to ground in any way, but i know they don't.

as long as the resistor is on that pot, you could move that cap to either position...  pin 3 or 2... and it will still work. but it will sound different in each place.

i know ya don't believe it. watch the video. there is no denying that the snarl pot works as shown.
i wish i knew how to do one of them spice simulation programs.

that said, you can indeed tie lug one to ground. it will function. but it doesn't do the same stuff when the pot is all the way down if grounded. you can do it either way, but no connection, it does still work, and that's where the weird synthy brass and string sounds i get in the video live. defective pot? maybe?
beats me.

watch the video. try the circuit on the breadboard, instead of worrying about designing a pcb or vero for it. see for yourself if it works or not. that would be my advice.

what's throwing ya'll off is it's not a cookie cutter "way everyone does it" kinda dealio. but it's the same control as the tone control in the suzy q with one resistor added and the cap moved up one lug. it's all about feedback, remember? i must have said that 20 times in this thread. as long as the 3.9k resistor is there, the cap is connecting lug 3 and  lug 2 at varying resistances, to ground thru the cap. it's the only explanation i can see for why it can work. take the resistor off, it don't work, and the cap has to be connected to the wiper to make a connection to ground. put the resistor on, the cap is still connected to ground via the wiper, but you're getting feedback thru the resistor. i don't know why or how it works, again, i am far from an EE and totally about the 10,000 monkeys with 10,000 breadboards and 10,000 years.

all i can do is tell ya, and show ya, it works. if the video isn't good enough to show the point, then the next logical step is for some brave ass soul to try it on the breadboard. if it works, cool. if you prefer it tied to ground, cool. but if you're not gonna try it, please stop breakin' my balls that it can't work, as it's been working for over a year when i first DID it. was working the same on the one i gave dick... a nice very subtle treble cut that could also be used as well to make it kinda nasal and muted.

i think the issue here is all you guys are thinking dc.... which flows in one direction.
and i'm pretty sure we're dealing with ac..... which flows in both directions. audio is ac. dc is used for amplification in the stuff we do here... you superimpose audio onto dc, amplify the dc, block the dc with caps so the ac- the audio, now much larger... can get thru to whatever comes after it. this is repeated thruout the device until it's out put feeds another amp or a transducer. that's how amplifiers work pretty much... the ac goes for the ride.

all i can say is try it. i've been asking for someone to just try it first, not design boards or anything.

i can't explain why it works. sorry. best i can do is try. again, take the resistor off, and it doesn't work. move the cap connection to the wiper, and it works differently and sound different.. much more aggressive.  put the resistor on, and it works. you could connect the cap on either side of the resistor and it still works. but it sounds different depending on which side of the resistor you connect the cap to.

like i said, i will go down, open it up, and check for continuity between wiper and ground as jon suggested.
if i find some, that will explain the mystery... would have to be a short, maybe an unseen globule of solder.

but if i DON'T find that connection, what then?

if ya watch the video, it's obvious it works.

what's throwing ya'll is cuzza that resistor. it "shouldn't work" but it does. stick a fork in me after this tho.

a cap to ground after a resistor is a low pass filter. pretend for a second that's what we have here... a resistance (the pot and resistor) feeding the cap, which is grounded.

what we have here is that. ^^^^^ a low pass filter.

a high pass filter is a cap feeding a resistor to ground. if we think of the cap being bled into the resistance via the resistor,  what we have is a feedback loop..., yes? a quasi hi and lo pass filter in one, cuz the cap is connected to both input and output (like a bleeder cap on a guitar) via the feedback/"tapering" resistor.

so there's a low pass, a hi pass, and a bleed all going on at once sorta, or some combo thereof. right now, the pot is a rheostat, a changing resistance loop cuzza the tapering resistor. if ya add the third connection to ground, you gotta pot.

you have a changing resistance feeding the cap to ground... a low pass filter. the change in resistance is limited by the resistor added to the pot... effectively adding 3.9k between the pot and the cap.... but feeding back some of the signal to the input of the filter, also via the 3.9k pot.

i think there's something very basic and very stupid about this that everyone is missing, including me. i'm just trying to figure it out. bleed inside the pot? defective pot? i don't think so, there's a bunch of suzy q's out there with this in them that do the same thing.

with the pot fully ccw, the wiper of the pot connects to the cap to ground, with the equivalent of a resistor at the value OF that resistor between the circuit, cap, and ground. with the pot fully cw, the wiper still connects to ground via the same resistor, but that resistor is in parallel with the value of the pot... whatever resistance the pot is set at, divide it by 3.9k, and that value is what comes before the cap to ground.

oy vey. this makes my bwain hurt.

somebody try it, or don't. that is the ONLY way i can prove the point, as video evidence obviously isn't good enough.

fwiw, i wouldn't think it works either, looking at it. but it does.[/s]

[pinkjimiphoton]

ok... think of it as a low pass filter with a 50k pot and a 100n cap to ground from the wiper. signal goes in the top (pin 3) and out the wiper (pin 2) to the cap, which goes to ground.

what happens if there's a 3.9k cap between the pot's wiper, and the ungrounded side of the cap? still a low pass filter, but the frequency has changed.

what happens if we connect the tapering 3.9k resistor between  pins 3 and 2 of the pot and leave the cap where it is?

still have the filter, but it's response will change. still connects to ground thru the cap. easy breezy.

but oooops.... what happens if we move that cap to the input instead of the output of the pot, but leave the tapering resistor there? the pot is the same, the tapering resistor is the same, the cap is still connected to ground on one side and connecting the resistance to ground thru it... but something is weird, cuz now suddenly we have a weird voltage divider thing happening.

the cap still goes to ground as it did. it's still connected to the output of the pot, via the resistor. as ya sweep the pot, the resistance changes.

obviously, being a cap, it's gonna BLOCK any dc there. but it will let audio thru... and in this case bleed it to ground. the ac component waltzes right on thru that cap to ground.  the dc component doesn't enter the equation anymore in this part of the circuit... and the pot seems to "pan" between two different kind of sounds.

if the cap were to ground from the wiper, there'd be no arguement. the only diff is that there's that resistor there changing the taper of the pot, and bleeding some of the signal between input and output of the pot... and as well, the cap to ground.

gonna take someone MUCH smarter than me to suss this one out. but i think i'm close... it's the only way i could possibly figure out how the hell it can work. like i said, looking at it, i didn't think it could work either.
but it does.

hooking up the bottom lug (pin 1) to ground makes little difference. tho the difference is audible. actually, thinking about it, hooking up the bottom lug makes no sense, as then the electrons go to ground as turned down rather than thru the cap to ground.

where's RG when ya need him

off to my dungeon .... again....

[pinkjimiphoton]

computer about to die.... i like my crow with some ketchup please.

all will be revealed

gotta get my puter back on the charger

i know what happened. i apologize hard, i mean REAL hard. so make that crow feathers and all.

be back soon... stay tuned, get some locks in your socks, i'm ready for some lumps...

[pinkjimiphoton]

i let the magick smoke out.......

gonna take a lot of shots of tequilla to get that taste of crow gone....


my apologies. i couldn't figure out how the hell it could work either.

it's cuz i didn't notice that resistor.... well.... watch the video

hit me with your best shots. i can take it

[pinkjimiphoton]

ok.... correct wiring....

pin 3 of snarl pot to circuit
pin 2 of snarl pot to 3.9k resistor to 100n cap to ground
pin 1 unconnected for synthy sounds, or connected to ground for more fuzzular thickness, but less dynamics on the string/woodwind/brass sounds.

i decided, fwiw, to NOT connect pin one. connected its still good, but there's definitely a bit of difference between the two. please try both, see what you prefer.
it may be worth adding a switch.

again, sorry for the confusion. but i hope my insane mojo imaginings were entertaining. i gota get this laudanum belladonna tincture dialed in a little bit.

[bluebunny]

You the man, PJP!  What a dude.   

So you mean something like this?



So glad I don't have to burn all my physics books... 

[bluebunny]

P.S. Always entertaining, Pink.  Best telly I've watched in ages.   

[Jdansti]

i let the magick smoke out.......

gonna take a lot of shots of tequilla to get that taste of crow gone....


my apologies. i couldn't figure out how the hell it could work either.

it's cuz i didn't notice that resistor.... well.... watch the video

hit me with your best shots. i can take it

Real men eat crow, Jimi. Good job on a great pedal!

[pinkjimiphoton]

here ya go, WITH added synth/fuzz switch.

i thiMk it's right finally after a horrid birth process.

[pinkjimiphoton]

You the man, PJP!  What a dude.   

So you mean something like this?



So glad I don't have to burn all my physics books... 

it's all about that flux capacitor and how it warps physical time and space into ,,, ummm,,,,

yeah mark, that is it, perfect , mystery solved.

nice sounding pedal

once old pink remembers ya gotta let the magickk smoke OUT once in a while, apparently 

[pinkjimiphoton]

P.S. Always entertaining, Pink.  Best telly I've watched in ages.   

this one time....?


at band camp.......?

thanks john too.... wow. i didn't THINK this smoke was THAT good

in back to the future star trek land where physics don't apply..... lol

[Jdansti]

General question for the group: What's a good source for AC176 trannies?

[GGBB]

Great job Jimi - sounds great and the mystery is revealed. Only one small detail to point out - the "bottom" lug of the snarl pot you call pin #3 is actually pin #1 - only mentioning it for the sake of accuracy.

Here's the revised layout and PCB (300dpi) - I've added a volume control, LED resistor and pad, and pads to jumper the remaining pin either to pin #2 or to ground, or go out to a switch and 1M resistor for the synth/fuzz option :





EDIT: board size is 2.2x1.6"

[bloxstompboxes]

I'd say that was a diylc layout GGBB due to the looks of the components but then there is the text on the board and the gnd pour. What version of DIYLC is that or what software did you use?

[GGBB]

I'd say that was a diylc layout GGBB due to the looks of the components but then there is the text on the board and the gnd pour. What version of DIYLC is that or what software did you use?

I start out in DIYLC, then I process it with some custom code I wrote, then I finish it with Inkscape.

[pinkjimiphoton]

wow, gord, that looks pretty awesome, thanks man!

[duck_arse]

pheww. I'm glad this all went this way, and not the other. still, better crow than duck.

ggbb, how come fillets on tee junctions, but not pads? is that your code or your ink?

[GGBB]

ggbb, how come fillets on tee junctions, but not pads? is that your code or your ink?

Just never thought of it - maybe next time. They are done in DIYLC.

[digi2t]

ok.... correct wiring....

pin 3 of snarl pot to circuit
pin 2 of snarl pot to 3.9k resistor to 100n cap to ground
pin 1 unconnected for synthy sounds, or connected to ground for more fuzzular thickness, but less dynamics on the string/woodwind/brass sounds.

i decided, fwiw, to NOT connect pin one. connected its still good, but there's definitely a bit of difference between the two. please try both, see what you prefer.
it may be worth adding a switch.

again, sorry for the confusion. but i hope my insane mojo imaginings were entertaining. i gota get this laudanum belladonna tincture dialed in a little bit.

[Quackzed]

Sounds really nice man! and that 1M resistor on the synth/fuzz switch... well thats just classy!