pigtronix Resotron User manual

RESOTRON
RESONANT TRACKING FILTER
User’s Guide
All contents c Absara Audio LLC 2018

Contents
Contents 1
1 Welcome to The Resotron 2
1.1 Features:......................... 3
1.2 Safety Precautions . . . . . . . . . . . . . . . . . . . . 4
ThankYou........................ 4
2 Anatomy and Functions 5
2.1 The Interface . . . . . . . . . . . . . . . . . . . . . . 5
Jacks........................... 5
Knobs and Switches . . . . . . . . . . . . . . . . . . . 8
3 Getting Started 11
3.1 Basic Hook Up . . . . . . . . . . . . . . . . . . . . . . 11
3.2 GuidedTour....................... 12
4 Resotron Back Story: 14
5 Pigtronix Limited Warranty 15
1

1. Welcome to The Resotron
The Pigtronix Resotron is an all-analog stompbox that brings pitch-
tracking capabilities to the world of envelope filter pedals for guitar,
bass and beyond. The revolutionary PITCH mode in the Resotron
allows the filter to follow the notes you play rather than how hard you
hit the strings! This function causes the cutoff frequency of the filter
to move around based on what notes the musician plays in real time.
Traditional, UP and DOWN (velocity-controlled) envelope modes are
also included in the Resotron along with an EXPRESSION input for
foot-controlled filter sweeps and CV modulation.
The multi-mode filter at the heart of the Resotron can be set to Low
Pass (LPF), Band Pass (BPF) or High Pass (HPF) modes. Each of
these voices has a distinctive character which can be manipulated by
adjusting the PEAK knob to emphasize frequencies below, at or above
the position of the CUTOFF knob. As the PEAK is increased, the res-
onance or ”Q” of the filter becomes more extreme, up to the point
of self-oscillation. A SENSITIVITY control sets how dramatically the
pedal will respond to playing dynamics in the UP and DOWN envelope
modes, while a GLIDE control allows you to set how long it takes for
the filter to move between notes in the PITCH mode.
A push-button OSCILLATE function turns the Resotron into an analog
synthesizer pedal. This mode shorts out the PEAK knob, effectively
setting it to 100% while simultaneously activating a voltage-controlled
amplifier (VCA) in the output stage. With the OSCILLATE function
turned on, the CUTOFF knob sets the tuning of the synth effect while
the VCA instantly follows the volume of your input signal. The syn-
thesizer sounds created by the Resotron can also be radically altered
by switching between the LPF, BPF and HPF modes, each of which
2

CHAPTER 1. WELCOME TO THE RESOTRON 3
has its own distinctive waveform and modulation characteristics when
overdriven by the on-board compressor.
Before the signal from the input of the pedal hits the filter inside the
Resotron, it passes through an optical compression stage derived from
our Philosophers Tone pedal. The increased volume and punch from
the compressor can then be mixed into the audio signal using the
BLEND control without affecting the SENSITIVITY of the envelope.
The Resotron also has a TRIGGER (aka Sidechain) feature which
enables the musician to use an external audio source to modulate the
filter.
1.1 Features:
•24db/oct Filter based on the SSM2040 chip
•Low Pass, Band Pass & High Pass Filter options
•Velocity controlled UP & DOWN envelope modes
•Pitch Following envelope function with variable GLIDE
•BLEND control mixes in Philosophers Tone compression
•Expression pedal / 0-5V CV input modulates CUTOFF
•OSCILLATE mode for monophonic synth sounds
•Sidechain TRIGGER input for external audio
•Hardwired True Bypass Switching
•18VDC Power Supply Included
•100% Analog Design
•Circuit Design by Nick Cote
•Sound Design by David Koltai

1.2 Safety Precautions
The safety precautions listed below are intended to ensure your safety when-
ever you use the Resotron.
NEVER OPEN THE CASE - Never try to separate the two pieces of the
chassis from one another and/or modify the equipment. Opening this de-
vice will effectively void the warranty.
STOP USE IN CASE OF PROBLEM - Stop using the equipment if ever you
should notice smoke or a strange odor coming from it. Contact [email protected]
for service.
AVOID HIGH TEMPERATURES & HEAT BUILD UP - Never cover the
power supply with cloth or other objects. Built up heat creates a danger
of equipment deformation and fire. Do not expose the Resotron to direct
sunlight, heating devices, or other extreme temperatures.
USE SPECIFIED POWER ADAPTER ONLY - Be sure to use only the 18-
Volt DC 300mA Adapter that came with your Pigtronix Resotron.
DO NOT EXPOSE TO WATER/BEER - To reduce the risk of fire or electric
shock, do not expose your Resotron to rain or moisture. If water gets inside
the unit, turn off the power.
Thank You
The Resotron represents a decade of continuous R&D involving some of
the top minds in the audio industry. Pigtronix would like to formally thank
the following individuals for their help in creating the Resotron: Nick Cote,
Thomas Elliott, Cyril Lance, Howard Davis, Ben Artes, Ray Heasman, Steve
Turnidge, David Buchter, Fischer Mao, Vernon Reid, Doug Wimbish, Fredrick
Thordendal and Teddy Kumpel.
−Pigtronix
4

CHAPTER 2. ANATOMY AND FUNCTIONS 5
2. Anatomy and Functions
2.1 The Interface
Jacks

CHAPTER 2. ANATOMY AND FUNCTIONS 6
1. DC 18V - Use only the 18-Volt, 300mA, negative tip power
supply that came with your Pigtronix Resotron. Using the wrong
power supply is likely to result in a damaged pedal.
2. INPUT - Effect input. Plug in your instrument here.
3. OUT - Effect output. Plug in your amp, mixer, or DI box here.
4. EXPRESSION - The expression pedal input allows remote con-
trol of the filter cutoff. A passive foot-controller or active (0-5V)
CV signal can be used with the EXPRESSION jack to modulate
the cutoff frequency of the filter in parallel with the on-board en-
velope and pitch tracking systems. When a passive expression
pedal is used, the onboard CUTOFF knob sets the maximum
sweep range. Since the envelope and pitch following signals are
wired in parallel with the expression input, you can effectively
use an expression pedal as a wah, with an envelope riding on
top of it!
Note: Use a TRS (Stereo) cable to connect a standard, low-
impedance (20K) foot controller to the EXPRESSION jack.
Note: Use a TS (Mono) cable to send control voltage (0-5V)
signals into the EXPRESSION jack.
5. TRIGGER - The trigger input is an auxiliary source for the en-
velope follower and pitch tracking system. When the TRIGGER
jack is in use, the audio signal at the INPUT jack is disconnected
from the envelope follower and pitch tracking system that modu-
lates the filter in the Resotron. When using the TRIGGER input,
it is recommended that the BLEND knob be set fully counter-
clockwise. This allows the signal feeding into the TRIGGER
jack to control the filtering of the signal from the INPUT jack.
Turning up the BLEND knob when using the TRIGGER input
will feed the audio from the TRIGGER jack directly through the
compressor and into the main audio path, in parallel with the
signal from the INPUT jack.

CHAPTER 2. ANATOMY AND FUNCTIONS 7
Note: If identical audio signals are sent to both the INPUT
and TRIGGER jacks, a ducking effect will occur when feeding
when the BLEND control is set to 12-o-clock. To eliminate this
ducking phenomenon, flip the phase of the TRIGGER signal.

CHAPTER 2. ANATOMY AND FUNCTIONS 8
Knobs and Switches

CHAPTER 2. ANATOMY AND FUNCTIONS 9
6. ENGAGE - This footswitch turns the entire Resotron on and
off. When the engage light is turned off, the Resotron is true
bypassed.
7. CUTOFF - This knob sets the resonant frequency of the lter.
Depending on the FILTER MODE setting, this position of the
CUTOFF knob will produce dramatically different sounds.
8. PEAK - This knob sets the amount of resonance in the fil-
ter. When the PEAK knob is fully clockwise the VCF will self-
oscillate. This creates a sine wave drone that will continue to
play regardless of a signal at the INPUT jack. When the OS-
CILLATE switch is pressed in, the PEAK knob is shorted to
maximum.
9. SENSITIVITY - This knob sets the responsiveness of the en-
velope follower in the ENV UP and ENV DOWN modes only.
When the SENSITIVITY knob is fully counterclockwise the en-
velope follower is turned off.
10. GLIDE - This knob determines the rate of portamento for the
PITCH mode only. This is heard as the time it takes for the
filter cutoff to move between the notes you play. Lower GLIDE
settings provide a fast, snappy filter motion that jumps quickly
between pitches. Higher GLIDE settings cause a more legato
filter motion. When the OSCILLATE switch is pressed in, the
GLIDE function sets the time it takes for the sine wave voice
to move from one note to another. This is heard as a glissando
effect.
Note: Turning the GLIDE control fully counter-clockwise
will disable the portamento function, providing the fastest, most
accurate pitch-tracking.
11. BLEND - This knob mixes in Pigtronix signature Philosophers
Tone compression before the filter. This powerful optical com-
pression stage adds considerable volume and clean punch to the
audio signal, without changing the response of the envelope fol-
lower! The compression BLEND knob allows the Resotron to