Harmonic Percolator - make one!

[pinkjimiphoton]

maybe i am being obtuse..
when i say bass and treble, i was talking about the top or bottom of the waveform. i think the nomenclature i used was wrong, mah bad!

[garcho]

Bass is low frequency, not negative polarity. They're not connected in any way.

[Kesh]

Finally built one. 2n404, and some NPN in a matching top hat whose number escapes me. Standard consensus spec. Sounds great. Pretty dirty. Or pretty AND dirty.

Amusing pic (with a Green Russian BMP)

[pinkjimiphoton]

love the enclosures!!   

[Henry89789]

Yet another pedal I want to build.

Pink Jimi:  I went to Midwest Surplus Electronics .... I got some of those 2n2273 you mentioned and some NPN Si that I hope will include some 100-120 hfe. Let's see .... Thanks for turning us on to that supplier.

[pinkjimiphoton]

my pleasure brother! hope they work for ya... did ya buy the rest of 'em? i bought like, 50 of 'em i think...

[Henry89789]

No. I only bought 20. It seems that on every batch of germaniums that I have bought the HFEs are always advertised as being much higher than they turn out to be. How many 100 hfe and higher did you get out of the 50?  I think I am going to start a thread asking suggestions on what can be done with the lower HFE germaniums; What can be done with them in regard to building pedals that is.

[pinkjimiphoton]

ha! 100!! lol!!!!!!!

maybe 40-70 in a couple cases. a whole bunch of 16-30 hfe.

BUT... you can bootstrap 'em or something for more gain... basically i think ya make a darlington pair out of 2 of 'em.

not sure of the deets, but hopefully someone who's not a hack like me can explain it bro.

[duck_arse]

ah-hah! I've finally got my perko to the photo showing stage, but in the picture thread.

now we just got to get jazznoise up and running.

[Jazznoise]

ah-hah! I've finally got my perko to the photo showing stage, but in the picture thread.

now we just got to get jazznoise up and running.

Yes we do.

There's a board meeting tomorow to determine wether or not I get an I Grade for being sick the last few months. (Had an endoscopy the day before my 21st birthday party  ). If I get the go head I'll be diving back into this and heating up my iron.

Speaking of which, it's f*cking warm in Ireland today. Strange times

[pinkjimiphoton]

chris... hope all is good man... healing vibes and mega mojo to you my friend!!!!

[Jazznoise]

chris... hope all is good man... healing vibes and mega mojo to you my friend!!!!

Thanks Jimi! It'll be fine, just this build list is getting ridiculous! 

[garcho]

I love this thing, can't stop playing through it. I socketed the diodes and have been noodling with those, but I've discovered I like it best without any. It drives my amps nicely. Such a lovely dirt.

[pinkjimiphoton]

nice!  without diodes is like te's jerkulator. i really like it. clippage!!!! clippage,, suh!!!! 

[pinkjimiphoton]

guys, i came up with a simple mod or two for the perc, i was gonna be a bogart but decided to share. 

first up, the 91k resistor from the pnp's c to ground... change it to this:

pnp c >  39k resistor > top side of 50k linear pot > wiper of pot > 15k resistor > ground.  you still have the original 91k, but a useable range to dial in harmonics, sustain and grit.

i call it the "focus" mod. it lets you dial in the distortion, and compression, and it DOES behave like a percolator, if your guitar is turned down some, it will swell into single notes like a
percolator perking. it is cool as hell.

next, the "boo-tweak mod" i call it...
second mod, replace  the 750k feedback resistor between b and c of npn with a 470k resistor going into a 500k trimmer wired as a variable resistor. you can fine tune the output and response of the npn section, make the whole pedal a bit louder, and really dial in the tone.  you may wanna just mount a 500k pot on the top of the box and label it "tweak"

seriously... try this out. stupid pedal trick imminent, and oh well, there' goes the first potential entry for the contest!!! lol

now i gotta come up with something else.... but i wanted to share my lummoxed discovery with the brethren and sister....thren...

but i had to hip you guys to this. it's a great and useful mod.

[petey twofinger]

steve alibini / harmonic percolator parody :

http://youtu.be/cEfNlWrakRE

[pinkjimiphoton]

steve alibini / harmonic percolator parody :

http://youtu.be/cEfNlWrakRE

bwah!!!

[inductor]

first up, the 91k resistor from the pnp's c to ground... change it to this:

pnp c >  39k resistor > top side of 50k linear pot > wiper of pot > 15k resistor > ground.  you still have the original 91k, but a useable range to dial in harmonics, sustain and grit.

i call it the "focus" mod. it lets you dial in the distortion, and compression, and it DOES behave like a percolator, if your guitar is turned down some, it will swell into single notes like a
percolator perking. it is cool as hell.

That's interesting. I'll have to try it...

next, the "boo-tweak mod" i call it...

I raised this to the equivalent of 1.4Meg with a 2n3904 as the npn.

[pinkjimiphoton]

hey, welcome, inductor!

cool, yah, i could see that working. i didn't try going bigger than 1m on it cuz originally i just wanted to do what tim escobedo did... use common values. 1 meg is close enough for rocknroll with 750k, but the pot thing is hip, you can dial in the output and response of the pedal, make it a little louder if need be, or give it more sustain. too high and it doesn't sing, but get it in the right range and it dilates and swells... it's hip.

so... the focus mod... now forth forever to be known as the "damn stinkin' percolator" knob... use these values.

from collector of pnp (ge gain around 51 or so) replace 91k resistor with  a 47k resistor to the top lug of a 50k pot, linear, and put a 47r resistor from wiper to ground.
if you go lower than that, it starts to lose volume.

that lets you dial it in, and increase the gain from the stock percolator circuit. you can turn the percolator control down and have the classic percolator sound, or turn it up and dial up the harmonics and distortion. parallel octave up/downs. crazy shit. feedback chords.  insane.

and if ya turn it down and dial back your guitar knobs, it can clean up into an almost accoustic kinda sound.

this thing is hip.

i know, i know...video or it never happened.

well... maybe soon, i have to program a jmp1 tomorrow for the other guitarist in my country band so it's ready to go for a humondo benefit sunday... 10 bands in 7 hours, 40 minutes a piece on 2 stages, in which i play with three of the bands not including the house... ayyyyyy my brain hurts... but for a good cause. raffling off a telecaster signed by all the participants, an autographed frank zappa album, a bottle of patron, a case of wine, some handmade jewelry... and maybe a fuzz or two.

so.. bear with me.

[Mustachio]

Petey holy molly I was dying man omg ! Crazy Hilarious !

So I need to revisit this as well, And since I'm in the mood of drawing new pcb layouts from schems I'm gonna give it a try with what I find in this thread. Gonna try to go off Marks values and try some of the Jimi mods Ill let you guys know how it turns out!