Harmonic Percolator gut shots

[Doug_H]

Okay see if this link works:

http://webzoom.freewebs.com/martyb/harprc.mp3.zip

It's a sound sample of my build.  First two twangs are my tele straight into a small tube amp.  Next is with the HP full throttle.  Cheezy  lick stolen from a cool song by Jim Weider called "Bigfoot".

Weird, Marty... Yours doesn't seem as gainy as mine:

http://home.cfl.rr.com/dbhammond/Brick.mp3

(The tonefrenzy clip doesn't sound as gainy as mine either...?!?)

My clip is through a clean amp, lead tone is a humbucker, rhythm is single-coil turned down to 5. The pedal is at max gain with the volume around 2:00.

Maybe it's super-sensitive to pickup types or something???

Doug

[MartyB]

Doug,

 The sound level on mine gets alittle boost, but not much.  A crazy thing is that there are various orientations of both transistors that still pass an audible signal, resulting in different sounds - like heavily-gated blooming, squashed sounds.  Did you play with this at all?  I'm pretty happy with mine as is, though I used Si for Q1 and Q2.   If we could only peel off those wraps on the trannies and peek....

[Doug_H]

I used a 2n404a Ge for the first stage and a 2n3565 Si for the 2nd stage.

Doug

[Dan N]

Doug, I went from the perculator posted at HC. There is an unknown value resistor in that spot, so I guessed 220K. Look at the gif Marty posted. It could only go base to collector if you flipped the transistor, or if the transistor has a different pinout. I appreciate your feedback, but I'll stand by my layout.

Of course, I just woke up and the world is still a blur.

Marty, thanks for the photo and the sounds!

Dan

[Doug_H]

Doug, I went from the perculator posted at HC. There is an unknown value resistor in that spot, so I guessed 220K. Look at the gif Marty posted. It could only go base to collector if you flipped the transistor, or if the transistor has a different pinout. I appreciate your feedback, but I'll stand by my layout.

Hi Dan,

The schematic I used is linked on the first page of this thread. I developed it from some schems that Alf had posted a few years ago. He reversed them from some real percs he worked on. There seems to be a lot of variation in the details in different schems I've seen show up. And there are suggestions that the "real" ones varied somewhat.

In the end I don't really care what's "real" or not. I built something I really like the sound of and use. If everyone who builds one likes it, that's all that matters AFAIC.

Doug

[ragtime8922]

[/quote]Hi Dan,

The schematic I used is linked on the first page of this thread. I developed it from some schems that Alf had posted a few years ago. He reversed them from some real percs he worked on. There seems to be a lot of variation in the details in different schems I've seen show up. And there are suggestions that the "real" ones varied somewhat.

In the end I don't really care what's "real" or not. I built something I really like the sound of and use. If everyone who builds one likes it, that's all that matters AFAIC.

Doug

Amen!  

[MartyB]

Who can argue with good tone you're happy with?   Also wanting to know this mythical pedal better (without the $$$ expenditure) and what exactly it can do has been part of it for me.  I built at least one of Alfonso's versions and came up with a different sound than my most recent attempt at this.  Doug, one guy builds a by-the-book fuzz (or amplifier, or guitar), and the result for him is  "fuzzes sound like this."  Another guy builds a different fuzz, maybe biased differently, different transistors, filter caps and his idea of a fuzz sound is unique.   The original paperwork that came with the HP is posted on the Theremaniacs site:

http://pages.prodigy.net/chuckcollins/harmonic.jpg

The specifics about how, and to what degree the different fundamental harmonics are augmented is really interesting.  Could this sort of thing be measured with an oscilloscope you think?  Audio spectral analyser?

[DavidRavenMoon]

also the strange glass tubes might be "coils" of some sort...

REALLY old post... just for people reading this now...

those are diodes.

[Rob Strand]

The mystery ended with this version.  There was another thread "Harmonic Perkolator" with John Greene and George Giblet in April 2007; can't find the link,
https://www.diystompboxes.com/smfforum/index.php?topic=68649.20

Here's the original thread,
https://www.diystompboxes.com/smfforum/index.php?topic=55987.0

And the 2007 schematic,
http://www.fredric.co.uk/misc/HarmonicPercolator.sch.png

There's plenty of tweaks out there.