aion CRESCENT AMP DISTORTION User manual

CRESCENT AMP DISTORTION 1
PROJECT NAME
CRESCENT
BASED ON
EFFECT TYPE
PROJECT SUMMARY
DOCUMENT VERSION
MI Audio Crunch Box
A Marshall-like distortion pedal noted for its high-gain “stack of amps” tone.
Amp-Like Distortion 1.0.1 (2021-04-12)
BUILD DIFFICULTY
Intermediate
Actual size is 2.3” x 1.86” (main board) and 1.78” x 0.86” (bypass board).

CRESCENT AMP DISTORTION 2
TABLE OF CONTENTS
1Project Overview 7Enclosure Layout
2Introduction & Usage 8Wiring Diagram
3-4 Parts List 9Licensing
5Schematic 9Document Revisions
6Drill Template
INTRODUCTION
The Crescent Amp Distortion is an adaptation of the MI Audio Crunch Box, a tweaked hybrid of the
Marshall Guv’nor and Bluesbreaker first released in 2006.
It’s solidly in the family of Marshall-like pedals and is lauded for its high-gain “stack of amps” tone. It
has seen has seen at least five major versions since that time, with the fourth and fifth version being
renamed to the Super Crunch Box.
The Crescent is not a direct clone or copy of any of these versions, but rather a hybrid of several of them.
It’s most similar to version 3, but with an added option for 18V operation using a charge pump as well
as a clipping diode toggle switch (both features from V5, although our version had it long before V5 was
released!).
The updated version of the Crescent is mostly the same as the earlier 1590B version, with two major
changes. First, there is an internal slide switch allowing 9V or 18V operation to be selected. Second, the
Presence control has been relocated back inside the enclosure as a trimmer, as on the original Crunch
Box units. The presence control essentially just sets the range of the main tone control, so it doesn’t
need to be external.
The Crunch Box was the inspiration for another well-known high gain pedal, the Suhr Riot. An Aion FX
adaptation of the Riot is available called the Fusion Distortion.
USAGE
The Crescent has the following controls:
• Tone controls the treble response of the effect.
• Drive controls the amount of gain in the op-amp feedback diode clipping stage.
• Volume controls the overall output.
• Clipping (toggle switch) selects between 3 sets of diodes: 1x silicon, 2x silicon, or LEDs (stock). This
will directly affect the volume, which will need to be adjusted when changing this mode.
• An internal Presence control allows you to tweak the overall response of the tone knob.
• Voltage (internal slide switch) selects 9V or 18V operation.

CRESCENT AMP DISTORTION 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 (most 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
R1 1k Metal film resistor, 1/4W
R2 1M Metal film resistor, 1/4W
R3 1k Metal film resistor, 1/4W
R4 10k Metal film resistor, 1/4W
R5 1M Metal film resistor, 1/4W
R6 470R Metal film resistor, 1/4W
R7 1M Metal film resistor, 1/4W
R8 22k Metal film resistor, 1/4W
R9 22k Metal film resistor, 1/4W
RPD 2M2 Metal film resistor, 1/4W Input pulldown resistor.
LEDR 4k7 Metal film resistor, 1/4W LED current-limiting resistor. Adjust value to change LED brightness.
C1 22n Film capacitor, 7.2 x 2.5mm
C2 1n Film capacitor, 7.2 x 2.5mm
C3 100pF MLCC capacitor, NP0/C0G
C4 220n Film capacitor, 7.2 x 2.5mm
C5 100n Film capacitor, 7.2 x 2.5mm
C6 100pF MLCC capacitor, NP0/C0G
C7 1uF Film capacitor, 7.2 x 3.5mm
C8 22n Film capacitor, 7.2 x 2.5mm
C9 22n Film capacitor, 7.2 x 2.5mm
C10 10uF Electrolytic capacitor, 5mm Charge pump filter capacitor.
C11 470n MLCC capacitor, X7R Charge pump filter capacitor.
C12 470n MLCC capacitor, X7R Charge pump filter capacitor.
C13 10uF Electrolytic capacitor, 5mm Power supply filter capacitor.
C14 47uF Electrolytic capacitor, 5mm Reference voltage filter capacitor.
C15 100uF Electrolytic capacitor, 6.3mm Power supply filter capacitor.
C16 100n MLCC capacitor, X7R Power supply filter capacitor.
D1 1N5817 Schottky diode, DO-41
D2 1N914 Fast-switching diode, DO-35
D3 1N914 Fast-switching diode, DO-35

CRESCENT AMP DISTORTION 4
PARTS LIST, CONT.
PART VALUE TYPE NOTES
D4 1N914 Fast-switching diode, DO-35
D5 1N914 Fast-switching diode, DO-35
D6 1N914 Fast-switching diode, DO-35
D7 1N914 Fast-switching diode, DO-35
D8 5mm LED, 5mm, red diffused Can also use 3mm LEDs.
D9 5mm LED, 5mm, red diffused Can also use 3mm LEDs.
D10 1N5817 Schottky diode, DO-41
D11 1N5817 Schottky diode, DO-41
IC1 TL072P Operational amplifier, DIP-8
IC1-S DIP-8 socket IC socket, DIP-8
IC2 TC1044SCPA Charge pump, DIP-8
IC2-S DIP-8 socket IC socket, DIP-8
DRIVE 100kB 16mm right-angle PCB mount pot
TONE 10kC 16mm right-angle PCB mount pot
VOL. 100kB 16mm right-angle PCB mount pot
CLIP SPDT cntr off Toggle switch, SPDT on-off-on
PRES. 25k trimmer Trimmer, 10%, 1/4” Bourns 3362P or similar.
VOLT. SPDT slide Slide switch, SPDT E-Switch EG1271
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
CRESCENT AMP DISTORTION 5
2M2
1N5817
100uF
GND
+9V
100n
VA
100kB
100kB
1k
10k
1M
470R
1M
22n
TL072P
100pF
220n
TL072P
100n
100pF
1M
1N9141N914
1k
1n
10kC
22n
25k
22n
1N9141N914
1uF
VA
VB
VB
GND
GND
GND
GND
GND GND GND
GND
GND
1N914
1N914
GND
TC1044SCPA
GND
1N5817 1N5817
10uF
470n
GND
470n
GND
22k
10uF
22k
GND
VB
47uF
GND
GND
IN
OUT
RPD
D1
C15
C16
DRIVE
1
2
3
VOLUME
1
2
3
R3
R4
R5
R6
R2
C1 6
5
7
IC1B
C3
C4
2
3
1
IC1A
C5
C6
D8
D9
R7
D4D5
R1
C2
TONE
1
2
3
C8
PRESENCE
1
2
3
C9
D7D6
C7
84
D2
D3
CLIP
2
3 1
1
2
3
4 5
6
7
8
IC2 D10 D11
C10
C11
C12
R8
C13
R9
C14
VOLTAGE
2
3
1
GND

CRESCENT AMP DISTORTION 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.
0 1 2
CM
0 1
INCH
x: -0.65, y: +1.71 x: 0.65, y: +1.71
ø9/32” ø9/32”
x: -0.85, y: +0.66
ø1/4”
x: 0, y: +0.66
ø9/32”
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
CLIP TONE
DRIVE
FOOTSWITCHLED

CRESCENT AMP DISTORTION 7
ENCLOSURE LAYOUT
Enclosure is shown without jacks. See next page for jack layout and wiring.
125B

CRESCENT AMP DISTORTION 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.

CRESCENT AMP DISTORTION 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 cannot be 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
1.0.1 (2021-04-12)
Corrected a few mixed-up capacitor values in the parts list. (The schematic and Mouser spreadsheet
were correct.)
1.0.0 (2021-03-19)
Initial release.