aion TORUS User manual

TORUS LO-FI FUZZ 1
PROJECT NAME
TORUS
BASED ON
EFFECT TYPE
PROJECT SUMMARY
DOCUMENT VERSION
Mid-Fi Demo Tape Fuzz
A thick fuzz/distortion circuit designed to replicate the low-budget garage tones of an overloaded
cassette recorder.
Distortion / Fuzz 1.0.0 (2019-08-04)
BUILD DIFFICULTY
Beginner
Actual size is 2.3” x 1.86” (main board) and 1.79” x 0.86” (bypass board).

TORUS LO-FI FUZZ 2
TABLE OF CONTENTS
1Project Overview 7Enclosure Layout
2Introduction & Usage 8Wiring Diagram
3-4 Parts List 9Licensing
5Schematic 9Document Revisions
6Drill Template
INTRODUCTION
The Torus Lo-Fi Fuzz is based on the Demo Tape Fuzz by Mid-Fi Electronics. The Demo Tape Fuzz is a
throwback to the days of running a guitar into a cassette recorder and cranking the gain to overload it
and create distortion.
The circuit consists of two simple building blocks. It starts out with an op-amp gain stage. This is similar
to a Distortion+, so the low-pass frequency changes with the gain. (This is in contrast to most drive
circuits after the 1970s where the potentiometer instead controls the feedback resistor, so the low-pass
frequency remains constant.) Next, a basic Baxandall tone section allows adjustment of treble & bass.
The interesting thing about this circuit is that, like a cassette recorder, there are no clipping diodes, so
all of the distortion/fuzz sound is generated “unintentionally” by op-amp clipping. It can get pretty thick,
but retains its rough-around-the-edges character at all settings.
USAGE
The Torus has the following controls:
• Gain (called “Trim” in the original) controls the amount of gain in the op-amp stage, as well as
varying the low-pass filter.
• Treble forms half of the Baxandall tone control and allows adjustment of the treble frequencies.
• Bass forms the other half and allows adjustment of the bass frequencies.
• Volume controls the overall output of the effect.

TORUS LO-FI FUZZ 3
PARTS LIST
This parts list is also available in a spreadsheet format which can be imported directly into Mouser for
easy parts ordering. Mouser doesn’t carry all the parts—notably potentiometers—so the second tab lists
all the non-Mouser parts as well as sources for each.
View parts list spreadsheet →
PART VALUE TYPE NOTES
C1 1uF Film capacitor, 7.2 x 3.5mm
C2 1uF Film capacitor, 7.2 x 3.5mm
C3 10pF MLCC capacitor, NP0/C0G
C4 1uF Film capacitor, 7.2 x 3.5mm
C5 47n Film capacitor, 7.2 x 2.5mm
C6 4n7 Film capacitor, 7.2 x 2.5mm
C7 47n Film capacitor, 7.2 x 2.5mm
C8 100uF Electrolytic capacitor, 6.3mm
C9 47uF Electrolytic capacitor, 5mm
C10 100n MLCC capacitor, X7R
R1 1M Metal film resistor, 1/4W
R2 100k Metal film resistor, 1/4W
R3 100k Metal film resistor, 1/4W
R4 470k Metal film resistor, 1/4W
R5 470R Metal film resistor, 1/4W
R6 10k Metal film resistor, 1/4W
R7 3k6 Metal film resistor, 1/4W
R8 10k Metal film resistor, 1/4W
R9 10k Metal film resistor, 1/4W
R10 3k6 Metal film resistor, 1/4W
R11 10k Metal film resistor, 1/4W
R12 10k Metal film resistor, 1/4W
R13 100R Metal film resistor, 1/4W
LEDR 4k7 Metal film resistor, 1/4W
D1 1N5817 Schottky diode, DO-41
IC1 JRC4558D Operational amplifier, DIP8
IC1-S DIP-8 socket IC socket, DIP-8

TORUS LO-FI FUZZ 4
PARTS LIST, CONT.
PART VALUE TYPE NOTES
GAIN 25kB Potentiometer, 16mm right-angle
TREBLE 500kB Potentiometer, 16mm right-angle
BASS 100kB Potentiometer, 16mm right-angle
VOL. 100kB Potentiometer, 16mm right-angle
LED 5mm LED, 5mm, red diffused
IN 1/4" stereo 1/4" phone jack, closed frame Switchcraft 112BX or equivalent.
OUT 1/4" mono 1/4" phone jack, closed frame Switchcraft 111X or equivalent.
DC 2.1mm DC jack, 2.1mm panel mount Mouser 163-4302-E or equivalent.
BATT Battery snap 9V battery snap Optional. Use the soft plastic type—the hard-shell type will not fit.
FSW 3PDT Stomp switch, 3PDT
ENC 125B Enclosure, die-cast aluminum Can also use a Hammond 1590N1.

SCHEMATIC
TORUS LO-FI FUZZ 5
GND
1M
1N5817
100uF
25kB
100kB
GND
100kB
500kB
+9V
100n
VA
100R 10k
10k
47uF
GND GND
VB
100k100k
470k470R
10k
3k6
10k
10k
3k6
JRC4558D
JRC4558D
1uF
VA
VA
GND
GND
1uF
GND
10pF
1uF
47n
4n7
VB
47n
GND
R1
D1
C8
GAIN
1
2
3
VOLUME
1
2
3
BASS
1
2
3
TREBLE
1
2
3
IN
OUT
C10
R13 R11
R12
C9
R2R3
R4R5
R6
R7
R8
R9
R10
IC1A
2
3
1
IC1B
6
5
7
84
C1
C2
C3
C4
C5
C6
C7
GND

TORUS LO-FI FUZZ 6
DRILL TEMPLATE
Cut out this drill template, fold the edges and tape it to the enclosure. Before drilling, it’s recommended
to first use a center punch for each of the holes to help guide the drill bit.
Ensure that this template is printed at 100% or “Actual Size”. You can double-check this by measuring
the scale on the printed page.
Top jack layout assumes the use of closed-frame jacks like the Switchcraft 111X. If you’d rather use
open-frame jacks, please refer to the Open-Frame Jack Drill Template for the top side.
LED hole drill size assumes the use of a 5mm LED bezel, available from several parts suppliers. Adjust
size accordingly if using something different, such as a 3mm bezel, a plastic bezel, or just a plain LED.
x: 0, y: -1.20
ø15/32”
x: -0.775, y: -1.20
ø5/16”
CENTER (0,0)
ø3/8” ø1/2”
0.385”
0.625” 0.625”
ø3/8”
OUT DC IN
125B
VOLUME GAIN
BASS TREBLE
FOOTSWITCHLED
x: -0.65, y: +1.71 x: 0.65, y: +1.71
ø9/32” ø9/32”
x: -0.65, y: +0.41
ø9/32”
x: 0.65, y: +0.41
ø9/32”
0 1 2
CM
0 1
INCH

TORUS LO-FI FUZZ 7
ENCLOSURE LAYOUT
Enclosure is shown without jacks. See next page for jack layout and wiring.
125B

TORUS LO-FI FUZZ 8
WIRING DIAGRAM
125B
IN +VGND N.C. N.C. OUT
PCB
IN
GND +V +V JACK GND JACK
OUTIN
GND GND PCB
OUT
Shown with optional 9V battery. If battery is omitted, both jacks can be mono rather than one being stereo.
Leave the far-right lug of the DC jack unconnected.

TORUS LO-FI FUZZ 9
LICENSE & USAGE
No direct support is offered for these projects beyond the provided documentation. It’s assumed
that you have at least some experience building pedals before starting one of these. Replacements and
refunds cannotbe offered unless it can be shown that the circuit or documentation are in error.
All of these circuits have been tested in good faith in their base configurations. However, not all the
modifications or variations have necessarily been tested. These are offered only as suggestions based
on the experience and opinions of others.
Projects may be used for commercial endeavors in any quantity unless specifically noted. No
attribution is necessary, though a link back is always greatly appreciated. The only usage restrictions
are that (1) you cannot resell the PCB as part of a kit without prior arrangement, and (2) you cannot
“goop” the circuit, scratch off the screenprint, or otherwise obfuscate the circuit to disguise its source.
(In other words: you don’t have to go out of your way to advertise the fact that you use these PCBs, but
please don’t go out of your way to hide it. The guitar effects industry needs more transparency, not less!)
DOCUMENT REVISIONS
1.0.0 (2019-08-04)
Initial release.