Here's a collection of vero (stripboard) and tagboard guitar and bass effect layouts that we have put together covering many classic and popular effects in growing numbers. Many of these have been posted on freestompboxes.org, so check that site out for great discussions on building your own effect pedals. Enjoy the builds and please also visit us on Facebook and Twitter
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Tuesday, 10 September 2013
Pink Jimi Photon's Photonic Juergulator
Pink Jimi Photon's take on Interfax Harmonic Percolator and Escobedo's Jerkulator.
Read maestro Photon's complete description on FSB.
rock the f**k on!! the vid/audeo is outta sync, too.....arrrrgh who needs LSD?
thanks for the AWESOME layout miro!! i'm a gonna build it today if i get a chance, the original juergulator went in a hoss trade saturday... i gotta mid 70's epiphone crestwood for it!!
this thing sounds way better thru a large amp, the little dano hodad isn't capable of producing the octaves well. they're in there. prepare to have some fun. it tracks great, you can reproduce tones unlike a stock perc which kinda sounds different every time.
i am truly honored to have some of my humble hacks featured here.
thank you all for being such great peeps... now fire up them irons, and get busy...
PJP, What is up with the Tweak pot? Mine doesnt seem to change anything. Mind you I have all pots cranked. I do like the sound of it as is but Id like to know if there is a secret to getting some kind of differnce out of the tweak.
The tweak seems to make it all a little more mushy squishy when turned up, and a little tighter and more focused when counter clockwise. Very subtle. You almost have to want to hear it in order to:) Also I think the 'percocet' control should be wired with the 2 & 3 lug. (not the 1 & 1 lug :) What did you find onthetundra?
hi guys, yah, the tweak pot i found sounded best at 414k, so i just fixed it there (i was outta 1 meg pots, so series'd 2 500k trimmers). it DOES make a difference, but it's subtle... i agree with smarkalet, he describes it exactly as i found it... yes, it should be the 2 and 3 lug (or the 1 and 2, if it works backwards)on the percolate control. i can't ever seem to get a straight answer on pot lug numbering, shit conflicts.. i know the #2 connection is always the wiper, so i consider #1 to be the "top" or "first" connection from left to right. this thing also works well if ya add a starve control to the power supply!! even more weirdness as it gets starved. thanks for building it, i hope you guys diggit!! it's actually probably more escobedo jerkulator than percolator, but without those, it wouldn't exist. rock on peeps... peace out pink jimi
hey my friends, i just wanted to hip you to a quick revision on the juergulator. i finally have a couple days off to mess with the circuit some. i think i've improved on it... all the same sounds are in it, but it gets a bit more now. here's the deets... swap out the 50k harmonics pot for a 10k... now the harmonics pot will be more useful, instead of all bunched up near the top, and you'll gain a little more balls. also, it lowers the input impedance significantly and makes the juerg way more friendly to guitar knob tweaking, like a fuzzface. next up, take the "tweak" (or as i call it now, the "focus") pot and bump it up from 500k to 1 meg. you can go to TWO megs if you want to probably. this will make it much more obvious... almost like a tone or attack control... still subtle, but definitely more noticeable. you can also try raising the percolate value to 250 or 500k most likely, tho i haven't tried yet. this one i just finished is built to miro's excellent layout on tagboardeffects. miro, i can't thank you enough.. really really groovy layout!! i guess this makes it juergulator rev. 1 if you make the changes. all pots linear again, pnp ge russian mn25b, this one's hfe is 62 and a bc547, this time an hfe of 580. i think we can call it done. rock on, my brothers and sisters of diy talk soon peace pink jimi photon
the percolate control is much more interactive now with the change in input impedance and focus/tweak control. more harmonics now, and you can boost the gain of stage 2, adding some more sparkle or cut it to mellow it out a little.
i hope it works out for you if you build it. peace
Hi- I just wanted to let you know that the mn25b transistor is listed as MP25b. The stamp on the side in Russian manuscript looks like a large lower case n. But they are MP25b. The General Electric version is 2n44.
this thing keeps surprising the hell out of me. i thought it could use a little more volume. i found q2 doesn't matter much. but q1 sure seems to. and against what i thought would be logical, it is louder/gainier/more distorted the LOWER the hfe of the transistor.. i tried a whole bunch of 'em, the one i stuck with has a gain of maybe 40. much better.
q2 i ended up putting on a switch, one side is the stock with the bc547, the other side an AC176.
MAN... i'm sold. the two are very similar, yet worlds apart.. as expected, the ac is fuzzier sounding, and the bc a bit more strident. the octave response is different, as is the response of the focus control. with the si, it's almost like a tone control in a way...but with the ge, it's like... kinda.... controls the sustain, bloom and character of the fuzz.
tomorrow when gineen goes out, i'll shoot some video. i think you guys will approve.
pinkster, in your post from the 18th, you mention about swapping the 50k pot. for a 10k one. However, on the vero above, the harmonics pot. is shown as 100k, and the volume pot. is 50k - did you mean changing the 100k harmonics for a 10k?
hi alan, yes, my bad, the harmonics pot (i get confused easy sometimes, ha!! there's also a harmonics pot on the suzy-q) is shown as 100k. the stock was 50k. but what you need to do is change it to 10k. sorry for the confusion!! glad ya likes it... i really dig the way it sounds, so much in fact i'm probably gonna add it to my live board for this week's shows.
Hi pinkster - I've got an AC128 with a HFE of around 60, reckon that will do the trick with a BC547? On the diagram the Perc pot is labelled 1,1 - which way round should it be (the top one to lug 2 and bottom to lug 3?) Video demo looks awesome so can't wait to try this one. Rock on dude!
hi jack, your input from the guitar is pin one on top, pin 2 goes to the board, pin 3 to ground. i can never keep which pin is what, so much confliction of info my widdle bwain hurts. if it's backwards, reverse the outer two wires. hope that helps peace jimi
Hey Pinkster, I confused by some of the info on here although great that it is, can you finalise your set up regarding pots ? As far as I can make out you eventually went for or advise : perc - 100k lin, harm - 10k lin, tweak - 1M lin, volume 50k
And for the transisors you've basically said try out a mix of both to see what works but best to go with low Hfe's ? Also does it have to be a Germanium transistor ?
for transistors, i prefer really leaky low gain germanium ones. pretty much ANY transistors should work here as long as they're one npn and one pnp.
high beta transistors aren't as loud, but have a lot more distortion. lower gain ones are louder, and a bit smoother.
40-60 for q1 is probably good. seriously, i would just use sockets (i pick up surplus 6 pin DIP ic sockets and whack 'em in half, they work better than the SIP ones i think) and swap stuff around til it sounds good to YOU.
also, you may wanna try (if you have ge transistors) REVERSE beta in one... rotate it 180 degrees. in some cases, for some reason, that seems to sound better!
Thanks Jimi, all socketed up and ready to rip, just waiting on the pots in the post. I dont even have any near that can replace. Few days. Ive got a good selection of transistors maybe not the germanium ones, found them hard to find and with only three pins. Could you use the 4 pined ones and leave the can pin disconnected ?
Hey all, I've built this twice now and I'm getting nothing from it, just read through this thread again and now I'm REALLY confused about the pot wiring, could someone help?
Using this numbering is everything in the diagram correct? https://www.google.co.uk/search?q=POT+WIRING+DIAGRAM+NUMBERING&espv=210&es_sm=122&source=lnms&tbm=isch&sa=X&ei=aWNxUtiAN8uIhQfegoDICQ&ved=0CAcQ_AUoAQ&biw=1280&bih=899#facrc=_&imgdii=_&imgrc=nqNBA3nofqvZ4M%3A%3BPHMSf8zftopVWM%3Bhttp%253A%252F%252Fsound.westhost.com%252Fpots-f5.jpg%3Bhttp%253A%252F%252Fsound.westhost.com%252Fpots.htm%3B640%3B360
OK I built it again and got it working i used an AC178 and a BC547, also just to confirm the pot numbering is correct, the PERC pot connections are to 2 and 3 as you go down the veroboard. Thanks again pinkster, this thing is bad ass.
HI Jimi/ Mirosol thanks for this great project, I like that the transisor has such a great effect on the sound. I took Jimi's advice and tried a few but also settled with the AC128. I aslo tried an AF239S (omintting the can pin) but had absolutley no control over the hamronics especially. Ive got a long list of transisitors I want to try now !.
guys, i hate to say it, but there's a bug in this vero: http://www.diystompboxes.com/smfforum/index.php?topic=104404.msg946373#msg946373
"You will laugh over this. I realized I had kind of rushed when I tested this and found, first off, that I had Q2 in backwards. I flipped it and it suddenly sounded way meaner. However, it had this kind of weird, mis-biased, sub-octave thing going. I took a good look at my work next to Miro's layout, and found the 10k resistor next to Q1 was only linking the bottom four rows, not the bottom five as it should be. Fixed that and all is good!"
thanks to bret608 at diystompboxes for finding this bug... if you re-do your juerg, it should gain quite a bit of balls!!!
please let me know how it works out for ya, i haven't built miro's layout yet, tho i plan on building a limited run of 10 of 'em soon. thanks brothers peace jimi
I maybe a bit late to asking on this thread. But I've been building this beauty for about a year... finally got round to wiring it up this weekend. Its works... but it doesn't. Depending on what transistor I use , I either get guitar sound but no signal effect or a high pitched continuous feedback (through which I can hear the guitar distorted) whose frequency varies as a adjust the controls ( volume up - pitch up , tweek up - pitch up ) . I'm inexperienced and a bit ignorant about what's actually going, but could this be due to me using PNP germaniums (Mp25b) with an hfe of less then 10. And untested for hfe NPN ? or is it more likely different build fault ? Thanks if you got any ideas / help. :-)
fucker!! i had a whole reply and the damn computer just farted and i lost it.
check resistors for continuity, check for bridges, don't worry about germanium... try si to see if you can get it working.hollah back if still stuck. peace jimi
Hi Jimi, I knew it would sound sweeet if I could get it working! I checked as you said, and all alright. Plugged in again, and still the loud, high frequency sound with the distorted guitar just perceptable through it - like there was another signal getting in. I thought it might be the power supply , so I hooked up a battery instead and it works , no more high pitch loud continuous overtone. Do you think I'm using the wrong 9v power supply, or could it be something in-circuit/in-box ? Now i havent left room in the box for a pp9 , so I'l have to find a way sort out the problem or rig a batttery externally . Another quick question - my Perc Pot lug 3 (or 1) is not connected to anything - is this ok ? or should I connect it to an earth ? Anyway thanks for your help , really appreciated and thanks for the pedal - ace :-) :-)
try sending the unconnected terminal of the perc lug to ground and see if the problem goes away. it should just be a variable resistor. just a shot in the dark, but are the pot casings of all the pots connected to ground? i've found on some circuits that if they aren't, the circuit will do exactly as you describe. i remember when i built gus smalley's ousb i was like... wtf... this is bullshit... lol... just SCREAMACIOUS SQUEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEAAAALLLLLLLLLL....... til i went and grounded the pot casings. try that, hollah back. if NOT, i'd try another bypass switch temporarily... look real CLOSE to see if there's solder bridges anywhere. sometimes they can be so tiny as to be lmperceptible, but still allow enough feedback to squeal. some settings may oscillate more... if so, look around that part of the circuit... like, if your perc control is messing up when ya turn it, look at the solder joints. i think enough peeps have built this that you should be able to get it.
DUH!!!
I gotta learn to read. try another power supply. if you can't, you'll need to add decoupling to it... try a 220r resistor in line with b+ and add a 220u-ish filter cap. if THAT doesn't work, add a 100-470p cap to ground and bleed some of it to ground.
if that doesn't work, ummm..... maaaaayyyybe it's the power supply jack? tiny bridge, or melted terminal? hey, it happens to us all sometimes ;)
Hey Jimi , Thank you for your time with this ! I checked the tracks pretty carefully last night and they seem ok, I'm going to try a new power supply (the other was 500mA) when I get back tonight. Then, if that still growls, I'll try adding the 'decoupling' - does this involve adding the components you suggest in series from the +ve supply coming in ( b+? ) or is b+ something else ? The apha pots all have a plastic coat on their case - but I guess i could try and get in and get them to ground. I've got an off board battery rigged up too , so I can still play if all else fails. I'll let you know , Thanks again. :-)
check between the pins on your bypass switch and power jack too. you can pry the plastic covers off the alphas if ya need to. usually in a metal box that will be unnecessary. yeah, decoupling is just putting a filter between the power supply and circuit so the signal doesn't bleed into it and make shit weird. i tried to work ya up a cheezy graphic, dunno if it will post here right or not... if not, i will post a direct link. ;) forget trying to post a graphic....sheesh!! lol here's a link br'ah
hey Jimi, thanks again. Been working on it since I got in from work.. and sure enough one of your suggestions sorted it. I tried sending a battery supply through the jack instead of direct to the circuit - and back came the howl , so i changed the socket as you suggested and :-) :-) :-) its working . .. Thanks for all the other info I didn't get round to considering but I'm sure they and the decoupling will come in useful for the next project .. this is only my third build but is my favourite . Some great splurgy sounds and ringing har-moan-ics available, and some lovely bluesy distortion.
I used OC602 (hfe 80) for Q1 and put in the switch you suggested to allow selection between an AC176 and BC547b . There's certainly a difference.
I got it boxed up in black, gold controls and violet photon generator ... just gotta put your name on it. I'll try and post a link to a picture . Cheer Jimi . Many thanks
Hi! The video really convinced me in building this effect. But now I finished it I just get a very tame/normal fuzz sound out of it. I tried tons of trannies but I never get that 'LSD' sound. Could something else be wrong, besides the transistors?
I don't have the specific as described above (such OC602, AC176) It's 9v powered by a Visual Spot / sound adapter (always forget the right brandname)
i used the crummiest, leakiest low gain ge pnp in my build, it maybe has too good a tranny in it? i'm gonna be building another one soon, i gave the original away... will try and advise if ya are still having troubles. i would imagine ANY low gain pnp would work, probably doesn't need to be ge. on mine, i put a switch to go between ge/si on q1 if memory serves... the really acid tones in the video are probably a hallucination ;)
thanks for the info. I now used a MPSA13 en some vague russian MP39B (I think that's what is says on the tran). It's the best duo out of the transistors I tried. But still not 'it'. So any recommendations are still welcome! (but no hurry)
once i'd cured my initial fault , i had to try a few different combinations of transistor. before I got one that sounded good. (see above) , but it was trial and error in the end. an oc75 for Q1 worked well with the silicon BC547b for Q2 as well. it's well worth it once you get the combo right. good luck :-)
hi guys, i gave this to someone a year or so ago, and was bored today, so yep, built a NEW one. a tagboard effects dot blogspot dot com exclusive... ;) ok, first, a couple subtle changes to the circuit you MAY wanna try... first, make the input the WIPER - pin 2 - of the harmonics pot. leave harmonics pin one where it is, and put pin 3 to where pin 2 used to be on this layout ^^^^^^^ up top. this will make a subtle difference in the way the pot responds, kinda like the old les paul wiring, it shouldn't matter but it does, next, make that harmonic pot 1 MEG instead of 100k. the combination of the different wiring and the larger pot make a significant difference. next up, the first connection on the upper left has to go to perc pot 2. perc pot 1 will stay on row 3 hole one. take perc pot pin 3 and ground it. that will make that and the tweak (actually i was gonna call it focus) pot work better.
ok, now transitors. this is the photonic juergulator mk 2 here my friends...
make 'em both npn. make q1 germanium, make q2 silicon.
will work on the board as already populated and FUCK lot easier to get it going... i was plugging pnp's in forever, and found one that sounded REALLY good. i was amazed, the circuit came to life.
next change... output pot, take it up to 100k instead of 50k. opens it up more.
in the end, i used the following for transistors with ridiculously good results...
turns out i had mis-sorted some transistors, and what i thought was an ac125 was actually an ac176..... an npn, not a pnp.
so q1 : ge ac176 npn hfe: 95 uf: 119mv c 2.01 b 1.94 e 8.42
q2 si bc550 npn hfe 415 uf 699mv c 9,05 b 8.50 and dropping when my meter hit it...it's all about the biggass cap and the tied transistors e 8.48
voltage was 9.79
that's it... i know it seems weird, but every subsequent 176 i tried worked great.
something about that cap makes the whole thing weird. power down between transistor swaps, or it will make you crazy ;)
sorry for any hassle caused, these changes are easily reversible if you prefer the original juergulator.
i think i got this right, but here's a schematic with the "mk 2" changes... i built this today, sounds and works great! info on fsb and diy as usual peace out
make thev 47n input cap 470n instead, now them knobs can percolate. it's all about that fucking electro between the transistors... it holds a charge or something, i guess thats how the harmonics percolate.... if i was swapping transistors, it would still work.... for a minute or so... then fade out. makes it damnably hard to find good transistors, ya gotta short that cap to ground after power down if ya want any predictability i think., the bigger cap lets more bass in, and pretty much every npn ge i've tried around 100hfe, as well as every PNP around FIFTY hfe as long as it's ge seems to work. make your head spin faster than linda blair at a pea soup cannery. i'm still tinkering, will have a new schem drawn up soon with everything. really vast improvement, way less hit-or-miss AND can use the same vero miro cooked up. ya gotta love that. ;)
i believe the whole percolation thing comes down to that 47u cap holding a charge of "harmonics" and "percolating" them... if ya pull the ge transistor out, it will keep working and sound the same.... for a while... til the cap discharges.
so... if building a juerg or perc or jerk, my advice to save much hassle, heartache and time, is power down between each transistor swap, and discharge that electro. or expect ridiculous results.
turn knobs... watch nothing happen... then suddenly change when the cap starts discharging. can be VERY frustrating!!!!! if ya power down between swaps and discharge it tho, every time ya power up it will work right. if the cap isn't discharged? fuhgeddaboudit!!
arrrrgh,,, ixnay on the 470n, stay at 47. this thing is WEIRD, ya change the knobs, and wait for the sound to catch up. the 47 i had wrong, i don't even know how the hell it was working, late nite stoned soldering should be avoided by guys called pink i guess. ;) sorry for any inconvenience. new schem will be up soon.. peace out peeps
what happened when you put in the 470n input cap? i grabbed 470n's before i noticed you redacted that mod and don't have any 47n's on me to test the difference, but with the 470n, the harmonic only works when fully opened and the signal is pretty weak. theres not a big change in volume or fuzz when the pedal is on/off
what happens with a 470n cap is you roll off about 80 % of the bass so it works more like a treble boost. it's just way too small. try 47n, 100n, 220n, 22n whatever. value isn't that crucial. use your ears and see what sounds best to you. the bigger the cap, the more lo end, and the stronger the fuzz effect generally. hope that helps you man. peace out photon
hey thanks for the quick reply! i did replace the 470n with 47n and get the treble boost. i can't figure out what's wrong then, it seems the harmonic pot only works from about 90%-100% open. once you roll it down past 90% i just lose my signal. it is a 1M linear too... lug 1 to 10k grounded, lug 2 to input, lug 3 to the input cap 47n. really confused.
ho bones, no man, a 470n should give it MORE balls, 47n should be less with a boost to the treble but not much more. sounds to me like you may need to play with the transistors. there's nothing in stone there. some transistors as a pair play nice, some don't. in my experiments i found damn near anything would work. are you sure also your pot is good? the 10k resistor is just to keep the input from grounding all the way. perhaps you're using a 1m audio or reverse log pot? if sall the action is in the last 10% it sounds like that may be the issue too. a reverse log pot will give you most of the action in the final 10% or the turn. it should be a one meg linear for best results. did ya socket your transistors? if so, play with them. i found you can pretty much plug anything in, in some cases even reverse bias them and get a better sound. it's not all that critical. the extra pots are very subtle and mostly just fuck with the bias a little. good luck and keep us posted please. rock on ~pjp
so it's definitely a "B1M" pot. tranny q1 is a gt404a which is what I found in place (or they are the same?) of ac176 and q2 is bc550. I feel tone wise is sounds cool, but is missing something which I'm hoping is due to the harmonic pot. I'm going to swap the pot with another and see what happens tomorrow. unless you have an idea. don't have any other trannies besides more of q1 & q2 right now either.
yeah, switching the pot did nothing. i'm not getting any balls to this pedal at all. sounds more like a wet fart. i'm wondering if i'm mixing up versions somehow. i'm assuming the stripboard version is a little more different than the schematic you posted january 2015 than i had originally thought.
stripboard version on this page works great, i built like 20 of 'em. this layout is better than my original one was. i would suspect either the big cap that ties to the two trannys is shorted, or you need a better gain ratio with the transistors. when this fucker comes alive, there's no mistaking it. did ya socket the transistors? pay no attention to gains or tranny types.. i've built these things npn, pnp, npn and pnp, silicon, germanium.. just about anything should work. i wish i could help ya more man. gotta 3904 and a 3906? it's almost the escobedo jerkulator with them, and that should be high enough gain to fire. make sure the perk and tweak pots are about half way up, and make sure ya power down and discharge the 47u cap before switching transistors. that cap will store a charge enough where on the breadboard i found i could pull a tranny sometimes with it running with very little effect on the sound til the cap discharged. this is one of them true "mojo" circuits... there's more going on i think than meets the eye. good luck bones, keep me posted. i have no doubt you'll figure it out. you may wanna lift the ground on the diode clipper too, they really aren't all that necessary to the circuit imho and may actually be contributing to the crappy tone. "they" say tack a diode clipper on the end to get more output, but i disagree, sometimes all it does is give ya a bit more compression of the signal (clipping the peaks with a ge diode can be a lot smoother and tube-ier ) and seems to me to actually kill output more than increasing it. a shorted diode there... easy to do with ge... could also fuck the whole thing up. whatever it is, it's gonna be something dumb... it always is. don't give up bro, you'll get it. ;)
hey pink, thanks for your help. came across the transistors from the original pedal and threw those in. this pedals sounds great in chain with another distortion/fuzz. i guess i got a bum set of trannies because those a404 didn't look like the ones i just bought haha.
This one was on my To Do list for a few years, finally built this past weekend. It's a solid fuzz pedal (thank you, Jimi!) .
It cleans up well at lower volumes, responds well to pick attack (soft and hard), and can dial in sounds from a cleaner overdrive to a full-on fuzz. I ran it through a Vox AC4 a touch below breakup and it sounded great.
BEFORE YOU BUILD, READ THIS: Three changes I made to what is on the layout: 1. FLIP Q2 2. Top-left Perc 1 wired instead to Perc 2 3. Harmonics pot to 10k (I used log, didn't have a linear)
Jimi suggested this, I may go back and change: "make that harmonic pot 1 MEG instead of 100k. the combination of the different wiring and the larger pot make a significant difference."
thanks for the kind words, really glad you diggit. i revisited this lately and built a small run of them, i've kinda made some changes over the years but forget what the hell i did, lol. rock on! PjP
the vid/audeo is outta sync, too.....arrrrgh who needs LSD?
Don't you think PJP deserves a tag in the Popular Brands window?
ReplyDeleteI think he certainly does :)
Delete+m
Cool! http://tagboardeffects.blogspot.nl/search/label/PJP
DeleteHmm,first I thought-LSD is easyer to handle but now I want that thing
ReplyDeletethanks for the AWESOME layout miro!!
Deletei'm a gonna build it today if i get a chance, the original juergulator went in a hoss trade saturday... i gotta mid 70's epiphone crestwood for it!!
this thing sounds way better thru a large amp, the little dano hodad isn't capable of producing the octaves well. they're in there.
prepare to have some fun. it tracks great, you can reproduce tones unlike a stock perc which kinda sounds different every time.
i am truly honored to have some of my humble hacks featured here.
thank you all for being such great peeps...
now fire up them irons, and get busy...
yerg ya later
pinkster
miro,
ReplyDeleteplease check the fsb thread, i gotta favor to ask.
;)
Any transistor suggestions? Hfes? Demo video sounds good!
ReplyDeleteFSB thread has exact hFE values Jimi used in his original...
Delete+m
Ok! Thanks a lot!
DeleteShould we hang on for another PJP entry to the blog?
ReplyDeleteok! Concider this very fide. Don't have time to 'yerg' around with it now but it's working!
ReplyDeleteCheers SMarkAlet! Tagged!
Delete+m
PJP, What is up with the Tweak pot? Mine doesnt seem to change anything. Mind you I have all pots cranked. I do like the sound of it as is but Id like to know if there is a secret to getting some kind of differnce out of the tweak.
ReplyDeleteThe tweak seems to make it all a little more mushy squishy when turned up, and a little tighter and more focused when counter clockwise. Very subtle. You almost have to want to hear it in order to:) Also I think the 'percocet' control should be wired with the 2 & 3 lug. (not the 1 & 1 lug :) What did you find onthetundra?
Deletehi guys, yah, the tweak pot i found sounded best at 414k, so i just fixed it there (i was outta 1 meg pots, so series'd 2 500k trimmers). it DOES make a difference, but it's subtle... i agree with smarkalet, he describes it exactly as i found it...
ReplyDeleteyes, it should be the 2 and 3 lug (or the 1 and 2, if it works backwards)on the percolate control.
i can't ever seem to get a straight answer on pot lug numbering, shit conflicts.. i know the #2 connection is always the wiper, so i consider #1 to be the "top" or "first" connection from left to right.
this thing also works well if ya add a starve control to the power supply!! even more weirdness as it gets starved.
thanks for building it, i hope you guys diggit!!
it's actually probably more escobedo jerkulator than percolator, but without those, it wouldn't exist.
rock on peeps...
peace out
pink jimi
hey my friends,
ReplyDeletei just wanted to hip you to a quick revision on the juergulator. i finally have a couple days off to mess with the circuit some.
i think i've improved on it... all the same sounds are in it, but it gets a bit more now.
here's the deets... swap out the 50k harmonics pot for a 10k... now the harmonics pot will be more useful, instead of all bunched up near the top, and you'll gain a little more balls. also, it lowers the input impedance significantly and makes the juerg way more friendly to guitar knob tweaking, like a fuzzface.
next up, take the "tweak" (or as i call it now, the "focus") pot and bump it up from 500k to 1 meg. you can go to TWO megs if you want to probably. this will make it much more obvious... almost like a tone or attack control... still subtle, but definitely more noticeable.
you can also try raising the percolate value to 250 or 500k most likely, tho i haven't tried yet.
this one i just finished is built to miro's excellent layout on tagboardeffects.
miro, i can't thank you enough.. really really groovy layout!!
i guess this makes it juergulator rev. 1 if you make the changes.
all pots linear
again, pnp ge russian mn25b, this one's hfe is 62
and a bc547, this time an hfe of 580.
i think we can call it done.
rock on, my brothers and sisters of diy
talk soon
peace
pink jimi photon
Thanks for that pinkster - I was wondering what hfe's to go for.
ReplyDeletesocket and experiment, brother alan..
ReplyDeletelet us know what works best to YOUR ear!
i just boxed the "revision"...
the percolate control is much more interactive now with the change in input impedance and focus/tweak control. more harmonics now, and you can boost the gain of stage 2, adding some more sparkle or cut it to mellow it out a little.
i hope it works out for you if you build it.
peace
Hi- I just wanted to let you know that the mn25b transistor is listed as MP25b. The stamp on the side in Russian manuscript looks like a large lower case n. But they are MP25b. The General Electric version is 2n44.
ReplyDeleteGreat. Now I have 6 projects to do.
thanks mike 19!! great transistors for fuzzes. i LOVE russian trannys
ReplyDeletewait, that didn't come out right at all 8)
WOW! hahaha!
ReplyDelete8)
ReplyDeletethis thing keeps surprising the hell out of me.
ReplyDeletei thought it could use a little more volume. i found q2 doesn't matter much.
but q1 sure seems to. and against what i thought would be logical, it is louder/gainier/more distorted the LOWER the hfe of the transistor..
i tried a whole bunch of 'em, the one i stuck with has a gain of maybe 40. much better.
q2 i ended up putting on a switch, one side is the stock with the bc547, the other side an AC176.
MAN... i'm sold. the two are very similar, yet worlds apart.. as expected, the ac is fuzzier sounding, and the bc a bit more strident.
the octave response is different, as is the response of the focus control. with the si, it's almost like a tone control in a way...but with the ge, it's like...
kinda.... controls the sustain, bloom and character of the fuzz.
tomorrow when gineen goes out, i'll shoot some video. i think you guys will approve.
peace
http://www.youtube.com/watch?v=s9xZSEsMxzY
ReplyDeletevideo of the final incarnation
pinkster,
ReplyDeletein your post from the 18th, you mention about swapping the 50k pot. for a 10k one.
However, on the vero above, the harmonics pot. is shown as 100k, and the volume pot. is 50k - did you mean changing the 100k harmonics for a 10k?
The Juergulator sounds fantastic now, by the way.
hi alan,
ReplyDeleteyes, my bad, the harmonics pot (i get confused easy sometimes, ha!! there's also a harmonics pot on the suzy-q) is shown as 100k. the stock was 50k. but what you need to do is change it to 10k. sorry for the confusion!!
glad ya likes it... i really dig the way it sounds, so much in fact i'm probably gonna add it to my live board for this week's shows.
Hi pinkster - I've got an AC128 with a HFE of around 60, reckon that will do the trick with a BC547? On the diagram the Perc pot is labelled 1,1 - which way round should it be (the top one to lug 2 and bottom to lug 3?) Video demo looks awesome so can't wait to try this one. Rock on dude!
ReplyDeletehi jack,
Deleteyour input from the guitar is pin one on top, pin 2 goes to the board, pin 3 to ground.
i can never keep which pin is what, so much confliction of info my widdle bwain hurts.
if it's backwards, reverse the outer two wires.
hope that helps
peace
jimi
Russian trannies came today. These are some pretty big cans!
ReplyDeleteMy wife is like, "you sure have been getting a lot of weird mail lately"
Mike
Hey Pinkster,
ReplyDeleteI confused by some of the info on here although great that it is, can you finalise your set up regarding pots ? As far as I can make out you eventually went for or advise :
perc - 100k lin, harm - 10k lin, tweak - 1M lin, volume 50k
And for the transisors you've basically said try out a mix of both to see what works but best to go with low Hfe's ? Also does it have to be a Germanium transistor ?
hi jim,
ReplyDeletein the end, i used the values you noted.
for transistors, i prefer really leaky low gain germanium ones. pretty much ANY transistors should work here as long as they're one npn and one pnp.
high beta transistors aren't as loud, but have a lot more distortion.
lower gain ones are louder, and a bit smoother.
40-60 for q1 is probably good. seriously, i would just use sockets (i pick up surplus 6 pin DIP ic sockets and whack 'em in half, they work better than the SIP ones i think) and swap stuff around til it sounds good to YOU.
also, you may wanna try (if you have ge transistors) REVERSE beta in one... rotate it 180 degrees. in some cases, for some reason, that seems to sound better!
Thanks Jimi, all socketed up and ready to rip, just waiting on the pots in the post. I dont even have any near that can replace. Few days. Ive got a good selection of transistors maybe not the germanium ones, found them hard to find and with only three pins. Could you use the 4 pined ones and leave the can pin disconnected ?
DeleteHey all, I've built this twice now and I'm getting nothing from it, just read through this thread again and now I'm REALLY confused about the pot wiring, could someone help?
ReplyDeleteUsing this numbering is everything in the diagram correct?
ReplyDeletehttps://www.google.co.uk/search?q=POT+WIRING+DIAGRAM+NUMBERING&espv=210&es_sm=122&source=lnms&tbm=isch&sa=X&ei=aWNxUtiAN8uIhQfegoDICQ&ved=0CAcQ_AUoAQ&biw=1280&bih=899#facrc=_&imgdii=_&imgrc=nqNBA3nofqvZ4M%3A%3BPHMSf8zftopVWM%3Bhttp%253A%252F%252Fsound.westhost.com%252Fpots-f5.jpg%3Bhttp%253A%252F%252Fsound.westhost.com%252Fpots.htm%3B640%3B360
OK I built it again and got it working i used an AC178 and a BC547, also just to confirm the pot numbering is correct, the PERC pot connections are to 2 and 3 as you go down the veroboard. Thanks again pinkster, this thing is bad ass.
ReplyDeletesorry jack roper, been on the road again so i was just checking in... glad you got it going, and that you diggit!!
Deleterock on!
jimi
Cheers man, for the record settled on an AC128 which measured 61hfe :)
ReplyDeleteHI Jimi/ Mirosol thanks for this great project, I like that the transisor has such a great effect on the sound. I took Jimi's advice and tried a few but also settled with the AC128. I aslo tried an AF239S (omintting the can pin) but had absolutley no control over the hamronics especially. Ive got a long list of transisitors I want to try now !.
ReplyDeleteguys, i hate to say it, but there's a bug in this vero:
ReplyDeletehttp://www.diystompboxes.com/smfforum/index.php?topic=104404.msg946373#msg946373
"You will laugh over this. I realized I had kind of rushed when I tested this and found, first off, that I had Q2 in backwards. I flipped it and it suddenly sounded way meaner. However, it had this kind of weird, mis-biased, sub-octave thing going. I took a good look at my work next to Miro's layout, and found the 10k resistor next to Q1 was only linking the bottom four rows, not the bottom five as it should be. Fixed that and all is good!"
thanks to bret608 at diystompboxes for finding this bug... if you re-do your juerg, it should gain quite a bit of balls!!!
please let me know how it works out for ya, i haven't built miro's layout yet, tho i plan on building a limited run of 10 of 'em soon.
thanks brothers
peace
jimi
I maybe a bit late to asking on this thread. But I've been building this beauty for about a year... finally got round to wiring it up this weekend. Its works... but it doesn't. Depending on what transistor I use , I either get guitar sound but no signal effect or a high pitched continuous feedback (through which I can hear the guitar distorted) whose frequency varies as a adjust the controls ( volume up - pitch up , tweek up - pitch up ) . I'm inexperienced and a bit ignorant about what's actually going, but could this be due to me using PNP germaniums (Mp25b) with an hfe of less then 10. And untested for hfe NPN ? or is it more likely different build fault ? Thanks if you got any ideas / help. :-)
ReplyDeletefucker!! i had a whole reply and the damn computer just farted and i lost it.
Deletecheck resistors for continuity, check for bridges, don't worry about germanium... try si to see if you can get it working.hollah back if still stuck.
peace
jimi
That happens to me ! Many thanks Jimi ... I've got my head in the box now , will let you know how I get on. Cheers , Jim
DeleteHi Jimi, I knew it would sound sweeet if I could get it working! I checked as you said, and all alright. Plugged in again, and still the loud, high frequency sound with the distorted guitar just perceptable through it - like there was another signal getting in. I thought it might be the power supply , so I hooked up a battery instead and it works , no more high pitch loud continuous overtone. Do you think I'm using the wrong 9v power supply, or could it be something in-circuit/in-box ? Now i havent left room in the box for a pp9 , so I'l have to find a way sort out the problem or rig a batttery externally . Another quick question - my Perc Pot lug 3 (or 1) is not connected to anything - is this ok ? or should I connect it to an earth ? Anyway thanks for your help , really appreciated and thanks for the pedal - ace :-) :-)
Deletetry sending the unconnected terminal of the perc lug to ground and see if the problem goes away. it should just be a variable resistor.
ReplyDeletejust a shot in the dark, but are the pot casings of all the pots connected to ground?
i've found on some circuits that if they aren't, the circuit will do exactly as you describe. i remember when i built gus smalley's ousb i was like... wtf... this is bullshit... lol... just SCREAMACIOUS SQUEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEAAAALLLLLLLLLL.......
til i went and grounded the pot casings. try that, hollah back. if NOT, i'd try another bypass switch temporarily... look real CLOSE to see if there's solder bridges anywhere. sometimes they can be so tiny as to be lmperceptible, but still allow enough feedback to squeal.
some settings may oscillate more... if so, look around that part of the circuit... like, if your perc control is messing up when ya turn it, look at the solder joints. i think enough peeps have built this that you should be able to get it.
DUH!!!
I gotta learn to read. try another power supply. if you can't, you'll need to add decoupling to it... try a 220r resistor in line with b+ and add a 220u-ish filter cap. if THAT doesn't work, add a 100-470p cap to ground and bleed some of it to ground.
if that doesn't work, ummm..... maaaaayyyybe it's the power supply jack? tiny bridge, or melted terminal? hey, it happens to us all sometimes ;)
hollah back sir... peace
Hey Jimi , Thank you for your time with this ! I checked the tracks pretty carefully last night and they seem ok, I'm going to try a new power supply (the other was 500mA) when I get back tonight. Then, if that still growls, I'll try adding the 'decoupling' - does this involve adding the components you suggest in series from the +ve supply coming in ( b+? ) or is b+ something else ? The apha pots all have a plastic coat on their case - but I guess i could try and get in and get them to ground. I've got an off board battery rigged up too , so I can still play if all else fails. I'll let you know , Thanks again. :-)
ReplyDeletecheck between the pins on your bypass switch and power jack too.
ReplyDeleteyou can pry the plastic covers off the alphas if ya need to. usually in a metal box that will be unnecessary.
yeah, decoupling is just putting a filter between the power supply and circuit so the signal doesn't bleed into it and make shit weird.
i tried to work ya up a cheezy graphic, dunno if it will post here right or not... if not, i will post a direct link. ;)
forget trying to post a graphic....sheesh!! lol
here's a link br'ah
http://i605.photobucket.com/albums/tt137/pinkjimiphoton/bpsd_zps46441a3f.png
hey Jimi, thanks again. Been working on it since I got in from work.. and sure enough one of your suggestions sorted it. I tried sending a battery supply through the jack instead of direct to the circuit - and back came the howl , so i changed the socket as you suggested and :-) :-) :-) its working . .. Thanks for all the other info I didn't get round to considering but I'm sure they and the decoupling will come in useful for the next project .. this is only my third build but is my favourite . Some great splurgy sounds and ringing har-moan-ics available, and some lovely bluesy distortion.
ReplyDeleteI used OC602 (hfe 80) for Q1 and put in the switch you suggested to allow selection between an AC176 and BC547b . There's certainly a difference.
I got it boxed up in black, gold controls and violet photon generator ... just gotta put your name on it. I'll try and post a link to a picture . Cheer Jimi . Many thanks
http://i724.photobucket.com/albums/ww241/Jimmy_Barden/DSC_0614_zps398c2ae1.jpg
Deletehttp://i724.photobucket.com/albums/ww241/Jimmy_Barden/DSC_0613_zps9afe3d88.jpg
jimbo! that is awesome! thanks fot yhr pics, glad it all worked out!~
ReplyDeleteHi!
ReplyDeleteThe video really convinced me in building this effect. But now I finished it I just get a very tame/normal fuzz sound out of it. I tried tons of trannies but I never get that 'LSD' sound. Could something else be wrong, besides the transistors?
I don't have the specific as described above (such OC602, AC176)
It's 9v powered by a Visual Spot / sound adapter (always forget the right brandname)
i used the crummiest, leakiest low gain ge pnp in my build, it maybe has too good a tranny in it?
ReplyDeletei'm gonna be building another one soon, i gave the original away... will try and advise if ya are still having troubles. i would imagine ANY low gain pnp would work, probably doesn't need to be ge.
on mine, i put a switch to go between ge/si on q1 if memory serves... the really acid tones in the video are probably a hallucination ;)
thanks for the info. I now used a MPSA13 en some vague russian MP39B (I think that's what is says on the tran).
DeleteIt's the best duo out of the transistors I tried. But still not 'it'. So any recommendations are still welcome! (but no hurry)
once i'd cured my initial fault , i had to try a few different combinations of transistor. before I got one that sounded good. (see above) , but it was trial and error in the end. an oc75 for Q1 worked well with the silicon BC547b for Q2 as well. it's well worth it once you get the combo right. good luck :-)
Deletehi guys,
ReplyDeletei gave this to someone a year or so ago, and was bored today, so yep, built a NEW one.
a tagboard effects dot blogspot dot com exclusive... ;)
ok, first, a couple subtle changes to the circuit you MAY wanna try...
first, make the input the WIPER - pin 2 - of the harmonics pot. leave harmonics pin one where it is, and put pin 3 to where pin 2 used to be on this layout ^^^^^^^ up top.
this will make a subtle difference in the way the pot responds, kinda like the old les paul wiring, it shouldn't matter but it does,
next, make that harmonic pot 1 MEG instead of 100k. the combination of the different wiring and the larger pot make a significant difference.
next up, the first connection on the upper left has to go to perc pot 2. perc pot 1 will stay on row 3 hole one.
take perc pot pin 3 and ground it. that will make that and the tweak (actually i was gonna call it focus) pot work better.
ok, now transitors.
this is the photonic juergulator mk 2 here my friends...
make 'em both npn. make q1 germanium, make q2 silicon.
will work on the board as already populated and FUCK lot easier to get it going...
i was plugging pnp's in forever, and found one that sounded REALLY good. i was amazed, the circuit came to life.
next change... output pot, take it up to 100k instead of 50k. opens it up more.
in the end, i used the following for transistors with ridiculously good results...
turns out i had mis-sorted some transistors, and what i thought was an ac125 was actually an ac176..... an npn, not a pnp.
so
q1 :
ge ac176 npn
hfe: 95
uf: 119mv
c 2.01
b 1.94
e 8.42
q2
si bc550 npn
hfe 415
uf 699mv
c 9,05
b 8.50 and dropping when my meter hit it...it's all about the biggass cap and the tied transistors
e 8.48
voltage was 9.79
that's it... i know it seems weird, but every subsequent 176 i tried worked great.
something about that cap makes the whole thing weird. power down between transistor swaps, or it will make you crazy ;)
sorry for any hassle caused, these changes are easily reversible if you prefer the original juergulator.
peace out
pink
i think i got this right, but here's a schematic with the "mk 2" changes...
ReplyDeletei built this today, sounds and works great!
info on fsb and diy as usual
peace out
http://i605.photobucket.com/albums/tt137/pinkjimiphoton/10923595_10204891424518289_82871566_zps89e0fbd8.jpg
yeah nice! I will going to update my V1 to V2!
Deletecool, will, please let me know if it works out for ya.... curious to see if ya think it's an improvement or not.
Deletethanks
jimi
oooops... i mean pink ;)
make thev 47n input cap 470n instead, now them knobs can percolate. it's all about that fucking electro between the transistors... it holds a charge or something, i guess thats how the harmonics percolate.... if i was swapping transistors, it would still work.... for a minute or so... then fade out. makes it damnably hard to find good transistors, ya gotta short that cap to ground after power down if ya want any predictability i think., the bigger cap lets more bass in, and pretty much every npn ge i've tried around 100hfe, as well as every PNP around FIFTY hfe as long as it's ge seems to work.
ReplyDeletemake your head spin faster than linda blair at a pea soup cannery.
i'm still tinkering, will have a new schem drawn up soon with everything. really vast improvement, way less hit-or-miss AND can use the same vero miro cooked up.
ya gotta love that.
;)
prototype built and working.
DeleteALL the knobs work well now, way more fuzz..
i believe the whole percolation thing comes down to that 47u cap holding a charge of "harmonics" and "percolating" them... if ya pull the ge transistor out, it will keep working and sound the same.... for a while... til the cap discharges.
so... if building a juerg or perc or jerk, my advice to save much hassle, heartache and time, is power down between each transistor swap, and discharge that electro. or expect ridiculous results.
turn knobs... watch nothing happen... then suddenly change when the cap starts discharging. can be VERY frustrating!!!!! if ya power down between swaps and discharge it tho, every time ya power up it will work right. if the cap isn't discharged? fuhgeddaboudit!!
[img]http://i605.photobucket.com/albums/tt137/pinkjimiphoton/1974999_10204902969286901_420570977_zpsf929430c.jpg[/img]
arrrrgh,,, ixnay on the 470n, stay at 47. this thing is WEIRD, ya change the knobs, and wait for the sound to catch up.
Deletethe 47 i had wrong, i don't even know how the hell it was working, late nite stoned soldering should be avoided by guys called pink i guess. ;)
sorry for any inconvenience.
new schem will be up soon..
peace out peeps
what happened when you put in the 470n input cap? i grabbed 470n's before i noticed you redacted that mod and don't have any 47n's on me to test the difference, but with the 470n, the harmonic only works when fully opened and the signal is pretty weak. theres not a big change in volume or fuzz when the pedal is on/off
Deletewhat happens with a 470n cap is you roll off about 80 % of the bass so it works more like a treble boost. it's just way too small. try 47n, 100n, 220n, 22n whatever. value isn't that crucial. use your ears and see what sounds best to you. the bigger the cap, the more lo end, and the stronger the fuzz effect generally. hope that helps you man. peace out
Deletephoton
hey thanks for the quick reply! i did replace the 470n with 47n and get the treble boost. i can't figure out what's wrong then, it seems the harmonic pot only works from about 90%-100% open. once you roll it down past 90% i just lose my signal. it is a 1M linear too... lug 1 to 10k grounded, lug 2 to input, lug 3 to the input cap 47n. really confused.
Deleteho bones, no man, a 470n should give it MORE balls, 47n should be less with a boost to the treble but not much more. sounds to me like you may need to play with the transistors. there's nothing in stone there. some transistors as a pair play nice, some don't. in my experiments i found damn near anything would work. are you sure also your pot is good? the 10k resistor is just to keep the input from grounding all the way. perhaps you're using a 1m audio or reverse log pot? if sall the action is in the last 10% it sounds like that may be the issue too. a reverse log pot will give you most of the action in the final 10% or the turn. it should be a one meg linear for best results.
Deletedid ya socket your transistors? if so, play with them. i found you can pretty much plug anything in, in some cases even reverse bias them and get a better sound. it's not all that critical. the extra pots are very subtle and mostly just fuck with the bias a little.
good luck and keep us posted please.
rock on
~pjp
so it's definitely a "B1M" pot. tranny q1 is a gt404a which is what I found in place (or they are the same?) of ac176 and q2 is bc550. I feel tone wise is sounds cool, but is missing something which I'm hoping is due to the harmonic pot. I'm going to swap the pot with another and see what happens tomorrow. unless you have an idea. don't have any other trannies besides more of q1 & q2 right now either.
Deleteyeah, switching the pot did nothing. i'm not getting any balls to this pedal at all. sounds more like a wet fart. i'm wondering if i'm mixing up versions somehow. i'm assuming the stripboard version is a little more different than the schematic you posted january 2015 than i had originally thought.
Deletestripboard version on this page works great, i built like 20 of 'em. this layout is better than my original one was. i would suspect either the big cap that ties to the two trannys is shorted, or you need a better gain ratio with the transistors. when this fucker comes alive, there's no mistaking it. did ya socket the transistors? pay no attention to gains or tranny types.. i've built these things npn, pnp, npn and pnp, silicon, germanium.. just about anything should work. i wish i could help ya more man. gotta 3904 and a 3906? it's almost the escobedo jerkulator with them, and that should be high enough gain to fire. make sure the perk and tweak pots are about half way up, and make sure ya power down and discharge the 47u cap before switching transistors. that cap will store a charge enough where on the breadboard i found i could pull a tranny sometimes with it running with very little effect on the sound til the cap discharged. this is one of them true "mojo" circuits... there's more going on i think than meets the eye. good luck bones, keep me posted. i have no doubt you'll figure it out.
Deleteyou may wanna lift the ground on the diode clipper too, they really aren't all that necessary to the circuit imho and may actually be contributing to the crappy tone. "they" say tack a diode clipper on the end to get more output, but i disagree, sometimes all it does is give ya a bit more compression of the signal (clipping the peaks with a ge diode can be a lot smoother and tube-ier ) and seems to me to actually kill output more than increasing it. a shorted diode there... easy to do with ge... could also fuck the whole thing up. whatever it is, it's gonna be something dumb... it always is. don't give up bro, you'll get it. ;)
hey pink, thanks for your help. came across the transistors from the original pedal and threw those in. this pedals sounds great in chain with another distortion/fuzz. i guess i got a bum set of trannies because those a404 didn't look like the ones i just bought haha.
Deleteawesome!! so glad ya got it sorted out bones!!!
Deleterock that shit and blaze on
LLAP
pink
thanks to jalmon salmon at fsb for the schem...
ReplyDeleteHEY BRO!
here's the original juerg schem
[img]http://i605.photobucket.com/albums/tt137/pinkjimiphoton/photonicjuergulatorschem_zps43a219c5.png[/img]
here's mk 2
[img]http://i605.photobucket.com/albums/tt137/pinkjimiphoton/juergulator_zpsf8649f71.jpg[/img]
thank u!
hope ya enjoy the fuzz ;)
stupid pedal trick, juerg mk ii
ReplyDeletehttps://www.youtube.com/watch?v=ANwLe6Yn1MI&feature=youtu.be
This one was on my To Do list for a few years, finally built this past weekend.
ReplyDeleteIt's a solid fuzz pedal (thank you, Jimi!) .
It cleans up well at lower volumes, responds well to pick attack (soft and hard), and can dial in sounds from a cleaner overdrive to a full-on fuzz. I ran it through a Vox AC4 a touch below breakup and it sounded great.
BEFORE YOU BUILD, READ THIS:
Three changes I made to what is on the layout:
1. FLIP Q2
2. Top-left Perc 1 wired instead to Perc 2
3. Harmonics pot to 10k (I used log, didn't have a linear)
Transistors I used:
Q1: MP16B (Russian 2N404), ~60hfe
Q2: BC547, ~580hfe
Jimi suggested this, I may go back and change:
"make that harmonic pot 1 MEG instead of 100k. the combination of the different wiring and the larger pot make a significant difference."
thanks for the kind words, really glad you diggit. i revisited this lately and built a small run of them, i've kinda made some changes over the years but forget what the hell i did, lol.
Deleterock on!
PjP