Harmonic Percolator - make one!

[pinkjimiphoton]

hi gus,
i'm trying to see if i can salvage the board i built, not looking possible, so gonna do a new layout based on the GG schem.
thanks for the help and advice!! be back shortly

[pinkjimiphoton]

ok, could probably have made this smaller or a little more elegant, but i wanted to see if i could salvage the original vero..
well, yes, i could salvage the board, but not the circuit. it has the same dimensions as the last one, but instead of going by brian's schem (which i fail'd epically on translating, sorry madbean!!! it's me, not your schem, i am an eeeeeeediot) i went by the george giblet schem instead.

gonna try and build this up instead..i MAY try to do it all on the original vero just to prove to myself i could...but ...naaaaaaaaaaah...

please...advice? did i get it right this time? it looks ok to me, but then, it did yesterday, too...



this is the george giblet "consensus" schematic, which i used for the above layout:



i noticed the part numbers are missing a few things, which i'm assuming are power filter and diode, which i'll just mount on the power jack.

look kosher? i hope?

[pinkjimiphoton]

ok, this one works.

EDIT:  THIS VERO LAYOUT IS VERIFIED

i gotta play with it some later to get the best fit for the trannys...right now, gotta mp16b (russian 404) in q1, and i dunno what in q2..but it's working.

surprisingly, other than the ge diode clipper, it SOUNDS like the harmonic jerkulator. not a whole lot of difference, other than the hj cleaning up better with the volume control.

the sub harmonix are there, everything, tho more subtle...probably cuz the transistors in there are too hot. but tonally?

escobedo pretty much nailed it, surprised how little mojo the actual circuit has over his adaptation. my opinion may change once i get the right transistors in there, but i dunno...stay tuned!

[digi2t]

Try an '828 in Q2. The ones I gave you are in the ball park for hfe with what's marked on the schematic.

Just for fun  .

[bluesdevil]

I built this one a few years back and could get the low octave ghost notes by using a very leaky transistor for Q1. Can't recall the exact hfe, but I'm pretty sure over 100hfe. I would definitely play around with this on the breadboard before committing to solder. Didn't keep notes so sure as hell can't remember what parts values I went with..... damn!!!!

[pinkjimiphoton]

Try an '828 in Q2. The ones I gave you are in the ball park for hfe with what's marked on the schematic.

Just for fun  .

i have the real low gain one ya gave me for the superfuzz, i ended up using one of the other 828's there...will try tonite, report back!

[pinkjimiphoton]

I built this one a few years back and could get the low octave ghost notes by using a very leaky transistor for Q1. Can't recall the exact hfe, but I'm pretty sure over 100hfe. I would definitely play around with this on the breadboard before committing to solder. Didn't keep notes so sure as hell can't remember what parts values I went with..... damn!!!!

lower gain super high leakage is the way to go...

or ya can get by with a 3906/3904 pair, probably. that's what's in escobedo's variant.

[pinkjimiphoton]

ok, dicked around some with the cct, and this is where i settled. i can still get a fair cleanup with my guitar volume control, and when cranked it sounds like the demo's i've heard...maybe an rch more polite. can't try it thru an amp at stage volume til tomorrow nite.

q1: 2n404 ge (top hat)
hfe : 43
e: 1.80
b: 1.68
c: 1.31

q2: bc639 (had to twist the legs around so b and c were right, as the 639 is ecb, not ebc) si
hfe 139
e:1.81
b: 2.38
c:2.81
this transistor Dino gave me for my superfuzz..nice sounding, as soon as i tried it the circuit came to life. tried a whole bunch of ge's for q1, some 2sc ge's i had, ac 128 (or was that 127?) mp16b, etc etc...
the 2n404, again, just seemed to bring it to life.

like mark said... build one!!

mark...thanks for the inspiration, bud, gus, thanks for the advice, everybody...thanks...build one!! they seem pretty oblivious to transistors, higher gain just makes it ruder..in some cases, rude to the point of significant 2nd harmonic.

the combo i used lets it clean up like a fuzzface...but sounds NOTHING like a fuzzface. going on my live board i think.

power supply was 9.47v

i get a little bit of a high pitched whine, so i gotta play with adding a real small cap or two to the cct to nuke it...may go away once it's boxed tho.

nice circuit, but for real, the escobedo one sounds real good, and real close.

i also used 1n34a's for the clipper, 100k l for harmonics and 50k l for level.
for the 91 k, i used an 82k and a 10k in series), for the 750k i used a 510k and a 220k in series..10k x 2 in series for 20k. worked right out of the gate.

i'll try and do a "stupid pedal tricks" tomorrow with the harmonic jerkulator to compare the two.
look forward to hearing mark's!!

the vero i did could probably be condensed a little bit, but it's already pretty small, and verified, if anyone wants a go at it.

[pinkjimiphoton]

[Mark Hammer]

Congrats!  I knew you'd you'd find something to tickle yourself with in that circuit.

It really doesn't sound like much else, but in a very good way.

Soundclips are a little awkward at the moment, but I'll see what I can do when the circumstance presents itself.  In the meantime, rock on.

[pinkjimiphoton]

all good mark!
indeed, it's different in a very cool way!! i like how at lower guitar volumes it does exactly what it says...makes a lot of very warm nice harmonics, and gets raunchy when you crank it. it's like a distortion that thinks it's a fuzz...real controllable.
i think doug hammond nailed it years ago  here: http://www.diystompboxes.com/smfforum/index.php?topic=68649.msg550551#msg550551
his suggestions for gain on the two transistors really seems to nail it.
a really leaky low-gain ge that probably wouldn't work in anything else is perfect for this thing.

i gotta question tho...since one of the transistors is ge, should we try using a reverse biased ge diode in parallel with e and b (or was it b and c? i gotta look) like the old plate to plate brit face to make it more impervious to temp changes?

living in new england, i'm sure this thing could get a bit fickle...my fuzzface is a lot more stable since i added that diode, and went to a different SI q2 in it.

[midwayfair]

a really leaky low-gain ge that probably wouldn't work in anything else is perfect for this thing.

You can even put the PNP in backwards! It'll do some oscillation stuff that way but otherwise sound very similar. (I had actually thought mine was backwards for a while before I paid more attention to the schematic, and it turned out to be oriented correctly.) The tolerance/bullet proofness of the Ge is one of the main draws of this circuit for me, especially because it uses a PNP (which is cheap) in an NPN circuit without any voltage inverter nonsense.

i gotta question tho...since one of the transistors is ge, should we try using a reverse biased ge diode in parallel with e and b (or was it b and c? i gotta look) like the old plate to plate brit face to make it more impervious to temp changes?

living in new england, i'm sure this thing could get a bit fickle...my fuzzface is a lot more stable since i added that diode, and went to a different SI q2 in it.

It's emmiter to base ... normally. However, remember the transistor is flipped around.

You can try it, I guess, but I didn't notice any temperature instability with mine, and I used it in a non-air conditioned house and a basement in the same recording session and never noticed an appreciable sound difference.

[pinkjimiphoton]

LOL!!

I HEAR YA ON THE FLIP IT EITHER WAY THING!!!

i find that on a LOT of GE fuzzes...if they're warm enough, it doesn't seem to matter at all!!

i was just curious about the diode trick, cuz here i have to change transistors a couple times a year...there's the summer ones, and the winter ones, in my fuzzface.

[pinkjimiphoton]

here ya go, the harmonic percolator:

[Paul Marossy]

Maybe I'll try again using this schematic - http://i605.photobucket.com/albums/tt137/pinkjimiphoton/HarmonicPercolatorsch.png
My first attempt has resulted in nothing but an oscillator circuit. I have given up on even trying to get it to work, it will only squeal like a pig being murdered. 

At least now I have that video from pinkjimiphoton to use as a reference point.

[pinkjimiphoton]

that's it paul, rock it bro!!

[inductor]

I modified the HP-1 abit based on Mr. Bill's values. Low Hfe 2n404's seem to work better - I have a bunch of high hfe 2n404's that I'll be trying the piggy back trick with. I removed the first pot, I think rolling off your guitar's volume knob works just as well. I believe the 1.5nf cap tightens up the fuzz it's still nasty/gnarly.

This schematic is abit dated just the +9 supply/led is different now. OH and I use a 50k vol pot.

http://www.inductorguitars.com/wp-content/uploads/2011/03/MP-1-schematic.png



There are a 4 youtube demos of my pedal. Don't want to spam...

[midwayfair]

here ya go, the harmonic percolator:

Great job. Very rich sounding, one of the best "concensus schematic" demos I've heard for sure.

... great, now I need to make another one of these ....

[Mark Hammer]

I liked the first one so much that I made a 2nd one for a buddy this evening.  Same schematic, except that the transistors were a 2SB175 with hfe around 52, and a 2N3904 with an hfe somewhere above 150.  Raunchier than the first one I made, but capable of the same tone.  I ran it through a Zombie Chorus set for a delay range that straddled the border of chorus and flanging.  Oh man, does it ever sound like the characteristic grunt/growl of a Leslie.

[newperson]

this thread got me poking around again about this pedal.  thought this link would be nice if someone would like to see the gut shots of one.

http://acapella.harmony-central.com/showthread.php?1008997-Rarer-than-hen-s-teeth