3PDT Harmonic Percolator Clone Kit: Review and question

[cnspedalbuilder]

I recently built a Harmonic Percolator clone kit from 3PDT.com (avail on Amazon). I don't see much about their kits on the forum so I thought I'd post a brief review and also ask you guys a tech question:

If you have heard anything about the Percolator, you know the association with Steve Albini of Shellac/Big Black/etc. As with Travis Bean guitars, Steve's endorsement for this long unavailable pedal, have led to crazy prices for original Percolators. The circuit has been cloned by a lot of pedal makers, and the 3PDT kit seems to be a clone of the clones FWIW, beyond Albini, this distortion circuit is supposed to be special because it minimizes odd order harmonics.

Kit Review:  this is a fantastic pedal. Strongly recommend building it from online schematics or from this kit.

Pros: The kit had some nice innovations. It comes w/daughterboard for 3PDT switch which minimizes the most tedious and annoying steps in wiring. Between the 3PDT board and a set of wires that plugs in directly to a jack in the PCB, even a slob like me can make the wiring neat and efficient. The PCB layout is clean, with in-board mounting of pots and LED, and the circuit is very simple and easy to put together. I'm sure many of you would find this kit to be boring b/c it is so easy, but as a newbie, I welcomed the simplicity.
  The biggest pro is the sound. I've seen many Percolator demos on youtube; each sounds pretty different and none particularly will make you sound exactly like Albini But unless you require an "authentic replica" this is all irrelevant. The versatility of this kit pedal is unbelievable, especially given its simplicity. The 2 pots are "harmonics" and "balance" which I believe means pre-gain and post-gain, and there is no tone knob. There's also a 3-way switch to toggle between germanium diode, silicon diode and no Diode. Between the toggle and the pots, the variety of tones that you can get is huge. I could get a fairly transparent sound that brought my blackface amp into maximum overdrive and a dirty, fuzzy gnarl that would take you close to Albini territory. With the middle toggle position, the pedal is also relatively noiseless, despite the huge gain that you get when you play. In just a night, I found sounds that I've never gotten from a distortion pedal before.

Cons: It doesn't produce as much feedback as I would've hoped and the toggle positions dramatically change the gain so any toggling will also necessitate some changes in pot settings. In terms of the kit, there are a lot of cut corners. First, some of the components are cheapo, especially the pots which are pretty inferior to ones from GGG and BYOC kits. In fact, the pots were not labeled, so I had to guess which was 50k and which was 100k. In retrospect I could've solved this w/a multimeter. Second, it doesn't come w/knobs, wires, and a few other little things. I already had wiring and don't need knobs for now, so no big deal, but again a novice might not. Also, although the kit can be built by a total novice, the included directions are so poor that I would not recommend it for someone w/o experience.

Question: As I said above, the middle position (not sure which it is) has WAYYY more gain than the other two positions, to my ear it's like a 30% increase. If anyone else has this pedal or a similar clone, do you have the same experience, or is it a component defect or assembly error on my part?

[duck_arse]

can you post some photos, especially of those pots? the pots are input level and output volume level. the volume changes are normal behaviour for switched diode-clipped circuits. you can adjust the volume w/ series resistors and switching messes, but who'd want another switch problem?

[cnspedalbuilder]

@DA: Yes I can post pics of PCB and pots, but I'll have to pull out the PCB to do it (should've taken pics beforehand!). As you know, I'm concurrently troubleshooting another pedal!

Thanks for info about clipping toggle btw. I certainly don't feel the need to mod it for now, esp because you can't switch clip settings on the fly anyway. But if one were to do this clone from scratch, it'd definitely make sense to have a second footswitch to toggle transistor vs. diode clipping and equalize gain across both circuits.

[Groovenut]

The pots on the website look to be knurled shaft 9mm Alpha type. 2N404a PNP for the transistor.

[thehallofshields]

The Germanium Diodes limit the signal swing to +/- 0.3V
The Silicon Diodes limit the signal swing to to +/- 0.6V
Without Diodes, the limit is determined by the Supply Voltage and Transistor configuration, which could be 10x that.

So you're getting exactly what you should expect out of the pedal.

[cnspedalbuilder]

Thanks this is good to know. I'm new enough that it seemed like everything came together too easy, but I guess I did it right! 

The pot that I used looked like the pic of a knurled shaft pot on Ebay:
http://www.ebay.com/itm/2-x-12mm-Alpha-A100K-100K-Audio-Taper-Potentiometer-Dual-Gang-D-Shaft-/262198040731

So it isn't cheapo, then? If so, I should edit my review! I thought it was cheap because it did not look as durable as the pots that BYOC and GGG supplies.

Regardless of the pot, the pedal is awesome. So many great sounds.

[youngks93]

Would you happen to know where I can find the bill of materials for this build? I can't find it anywhere and the full kits have been out of stock for a while 

thanks!!

[cnspedalbuilder]

Is that right? I know he doesn't keep em online. I'll see if I can find the printout. You will still need the PCB though.

There is also a clone kit here: http://shop.pedalparts.co.uk/Harmonic_Percolator/p847124_4550994.aspx Also, there are layouts for Percolators on Veroboard here: http://tagboardeffects.blogspot.com/search?q=percolator
If you already have the PCB this will help. Btw, it might be the case that 3PDT puts component names/values on the board if you have their pcb.


By the way I have had the 3PDT Percolator on my board for a while, and it is my favorite distortion/fuzz ever. I don't know if it sounds like Steve Albini's original, but who cares, it sounds like the wrath of God!

[cnspedalbuilder]

Actually here is a PCB from Madbean that has a bill of materials and even a variant for "Steves" pedal:
http://www.madbeanpedals.com/projects/PepperSpray/docs/PepperSpray.pdf

This is such a simple and elegant circuit, I think you will be happy whatever you choose.

[Gus]

Do a search of this forum for the HP there is some good information.

[youngks93]

Actually here is a PCB from Madbean that has a bill of materials and even a variant for "Steves" pedal:
http://www.madbeanpedals.com/projects/PepperSpray/docs/PepperSpray.pdf

This is such a simple and elegant circuit, I think you will be happy whatever you choose.

Thank you so much!

[Chrisfromiowa]

Can anyone post what they have either pcb or instructions, this is all I received from 123spring, the aliexpress vendor that I think became 3pdt. Thanks