OSIRIS DISTORTION/SUSTAINER
2
TABLE OF CONTENTS
1
Project Overview
7
Enclosure Layout
2
Introduction & Usage
8
Wiring Diagram
3-4
Parts List
9
Licensing
5
Schematic
9
Document Revisions
6
Drill Template
INTRODUCTION
The Osiris Distortion/Sustainer is adapted from the Black Arts Toneworks Pharaoh Fuzz, a Big Muff-
based circuit with a few modifications.
First, an input impedance switch has been added to the front of the circuit. By reducing the signal level
before the boost and clipping stages, you can match it to high-output instruments or earlier pedals in the
chain, or just reduce the overall signal level for more headroom and less clipping.
Second, a clipping switch has been added to control has been added to go between silicon and
germanium diodes in the second clipping stage. The silicon diodes are in the stock Big Muff for a familiar
sound, while germaniums will be more compressed and gainy, but also softer with a more rounded
clipping waveform.
Third, a “High” control has been added to the bass side of the tone control rotation allowing the low-pass
filter frequency to be adjusted. This restores some of the high end so you don’t have to choose between
a bass emphasis and treble emphasis.
USAGE
The Osiris has the following controls:
•
Hi/Lo
toggles between two different resistors on the input, which changes the amount of headroom
and clipping later in the circuit.
•
Si/Ge
toggles between silicon (stock) diodes and asymmetrical germanium diodes.
•
Sustain
controls the amount of drive or distortion, which also affects the amount of sustain.
•
Tone
is a the classic Big Muff balance control with a high-pass filter (treble emphasis) on one side
and a low-pass filter (bass emphasis) on the other.
•
High
allows you to vary the low-pass filter cutoff point on the bass side of the tone control,
restoring some of the high-end signal on the bass settings.
•
Volume
is the overall output.
