1. General Information
• -Two Face Fuzz
• -Lion
• -Lion X – Still looking

The Schumann PLL is a unique and interesting fuzz pedal that I stumbled onto a 5 or so years ago, but was never able to lay my hands on until Oct 2009. Created by John Schumann and out of production since around 2005(*) it appears that less than 100 units were made(*). Of those units there are said to be two versions of the circuit, the initial version said to be prone to noise, interference, and failure. The second version was supposed to solve some of these problems and added connect-ability for the Drone and Arpeggiation attachments, though it is believed that the Arp attachment was never produced(*).

The alleged way to tell the difference between the two versions are as follows: The face and knob screening is directly on the box in the 1st version and attached via a screwed on faceplate in the 2nd version, 2nd versions include the Arpeggiation and Drone connectors by default, though a number of 1st versions have said to have been modded to include the drone connector(*).

As cool as these pedals look externally, they are almost equally nightmarish internally. A combination of odd wire choices, mixed materials, questionable soldiering technique and several different materials used to ‘goop’ the circuits create a hellish circuit-scape that has limited cloning attempts of this pedal even as prices continue to increase on the secondary market.

Update: 8/19/2010
I was able to procure a second PLL earlier this month. This one is a later model and contains an extra switch (first one: #14, this one #54). A couple of the pots had been crushed, but I was lucky and it was an easy fix. After getting it rolling again, I decided I would keep this one, and send the other one to a new home! The momentary switch is also much more like one would expect, but sadly is broken… I’m trying to fashion a new one after looking at how this one is supposed to work.
Still no drone…

I’ll update this page as I gain new information, find problems, do more demos… etc.

* = Unconfirmed.

• Instruction Sheet (PDF)
• Settings Mapping Sheet (PDF)

Information from Schumman’s Page on the PLL:

SCHUMANN PLL
The PLL is an analog harmonizer that turns your input signal into a square wave and then has a multiplier and divider that adds intervals to your note.

Two harmony notes are controlled by the loop function which controls how it tracks your original note.

* makes one note into a chord
* make any triad out of one note
* makes it sound like there’s someone else playing along with you
* set the loop control to decide how it follows your playing
* the three notes are a three-channel mixer that gets into a master volume
* uses a +12 -12 bipolar power supply

Comes with the MOMENTARY switch accessory. This lets you mute the two harmony voices momentarily or turn them on momentarily.
The PLL Multiplier, Divider, Loop controls…

Some comments about the PLL:

it’s not easy to explain everything it does but put most simply, it’s a square wave generator that’s controlled by an input signal (guitar, synth, drum machine, etc). the ‘signature’ of the sound ultimately lies in the tracking circuit which is of itself an amazing thing. from my experience, most analog tracking circuits of this nature suck (MS20, sherman filterbank2, analogue systems pitch-to-CV) but the PLL gives unprecedented control over how accurately or inaccurately you wish it to track a signal, and can cause wonderfully lively twitches and bumps of the pitch (if you want). and though it can become chaotic, it’ll still be in key (or not, if you want). i’d describe the sound it generates as highly shapable harmonic-specific distortion. germanium overdrives act upon the squarewave and it’s multiplier and divider to add ‘beyond fuzz factory’ fuzz. the overall tone depth is determined by the levels of the square wave (root) and harmonics (mult and divider). the post-mix waveshaper does alot to tone-down or amp-up the front egde of the sound after you get your harmonics dialed in. there’s still other stuff you can mess with to alter the sound (like playing your instrument) but that’s it in a nutshell. — scott m.

Information from Schumman’s Page on the PLL Drone:

PLL DRONE accessory

The DRONE is an add-on to the PLL. Instead of stopping when you stop playing, the DRONE oscillates at a note that you play, with a foot switch to turn it on and off.

The drone function is a continuous sound generator that you can set to a specific pitch.

Video Demos by me:

The Unwrapping

Photo Gallery:

12►

PLL Momentary Switch:
So the ‘momentary switch’ that came with mine had a clearly broken toggle switch. I decided to take a swing at replacing it with one I have here, and now I think I have it totally working.
The switch allows you to have two modes available, allowing any combination of the Multiplier and Divider being ON/OFF in each of those modes.

It’s of course not wired in any way that makes sense, like the top switch is ON/OFF in main mode, and the bottom switch is ON/OFF in toggle. It’s a damn permutation problem with four switches and two positions each.
P = Switch Up
b = Switch Down
Fuzz is always on (assuming it has volume in the mixer)

Switch Position On On

Multiplier Divider Main -> Toggle
P P M&D M&D
P P

Multiplier Divider Main -> Toggle
P b M&D M
P P

Multiplier Divider Main -> Toggle
P b M M&D
P b

Multiplier Divider Main -> Toggle
P P M&D M&D
P b

Multiplier Divider Main -> Toggle
b P M&D D
P P

Multiplier Divider Main -> Toggle
P P M&D M&D
b P

Multiplier Divider Main -> Toggle
b P D M&D
b P

Multiplier Divider Main -> Toggle
b b D M
b P

Multiplier Divider Main -> Toggle
b b None M&D
b b

Multiplier Divider Main -> Toggle
b b M&D None
P P