Aion Electronics CYGNUS User manual

CYGNUS DISTORTION/SUSTAINER 1
PROJECT NAME
CYGNUS
BASED ON
EFFECT TYPE
PROJECT SUMMARY
DOCUMENT VERSION
Cornish G-2
Based on the classic Big Muff circuit, this pedal adds a meticulously-tuned buffered bypass along with an
additional transistor-based buffer stage on the effect input.
Distortion / Sustainer, Fuzz 1.0.0 (2019-03-14)
Actual size is 2.3” x 2.43” (main board) and 2.3” x 0.87” (bypass board).
BUILD DIFFICULTY
Intermediate

CYGNUS DISTORTION/SUSTAINER 2
TABLE OF CONTENTS
1Project Overview 8Drill Template
2Introduction & Usage 9Enclosure Layout
3-5 Parts List 10 Wiring Diagram
6Build Notes 11 Licensing
7Schematic 11 Document Revisions
INTRODUCTION
The Cygnus Distortion/Sustainer is adapted from the Pete Cornish G-2, a Big Muff-based circuit.
Cornish pedals are probably best known for being extremely expensive. There are two reasons for this.
First, the build quality and reliability is unmatched. Second, the mysterious nature of them, partially
due to the fact that the circuit is obscured and partially because of the A-list of clients. (The G-2 is most
famously used by David Gilmour.)
Inside, the circuit is a basic Big Muff with a few changes such as the use of germanium diodes for clipping
instead of silicon, and of course the famous class-A transistor buffer design. Both buffers together (the
bypass buffer and effect input buffer) have almost as many parts as the main circuit!
The Cygnus is a faithful reproduction of the G-2 circuit, but with one major update: an internal switch
allowing the pedal to be used in true-bypass mode instead of buffered bypass. As with the Klon KTR, the
buffer mode is “almost always better”, but you can be the judge of that.
USAGE
The Cygnus has the following controls:
• Sustain controls the amount of drive or distortion, which also affects the amount of sustain.
• Tone is a basic high-cut filter.
• Volume is the overall output.

CYGNUS DISTORTION/SUSTAINER 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 10M Metal film resistor, 1/4W
R2 1k Metal film resistor, 1/4W
R3 120k Metal film resistor, 1/4W
R4 120k Metal film resistor, 1/4W
R5 200k Metal film resistor, 1/4W
R6 7k5 Metal film resistor, 1/4W
R7 20k Metal film resistor, 1/4W
R8 51R Metal film resistor, 1/4W
R9 1M Metal film resistor, 1/4W
R10 1k Metal film resistor, 1/4W
R11 120k Metal film resistor, 1/4W
R12 68k Metal film resistor, 1/4W
R13 150k Metal film resistor, 1/4W
R14 8k2 Metal film resistor, 1/4W
R15 39k Metal film resistor, 1/4W
R16 100k Metal film resistor, 1/4W
R17 470k Metal film resistor, 1/4W
R18 15k Metal film resistor, 1/4W
R19 680R Metal film resistor, 1/4W
R20 1k Metal film resistor, 1/4W
R21 8k2 Metal film resistor, 1/4W
R22 100k Metal film resistor, 1/4W
R23 470k Metal film resistor, 1/4W
R24 15k Metal film resistor, 1/4W
R25 680R Metal film resistor, 1/4W
R26 8k2 Metal film resistor, 1/4W
R27 100k Metal film resistor, 1/4W
R28 470k Metal film resistor, 1/4W
R29 15k Metal film resistor, 1/4W
R30 100R Metal film resistor, 1/4W

CYGNUS DISTORTION/SUSTAINER 4
PARTS LIST, CONT.
PART VALUE TYPE NOTES
R31 100k Metal film resistor, 1/4W
R32 390k Metal film resistor, 1/4W
R33 100k Metal film resistor, 1/4W
R34 8k2 Metal film resistor, 1/4W
R35 2k2 Metal film resistor, 1/4W
R36 620R Metal film resistor, 1/4W
R37 39k Metal film resistor, 1/4W
R38 91R Metal film resistor, 1/4W
R39 49.9k Metal film resistor, 1/4W Original is 50k. This is the closest available value. Can also use 51k.
R40 100R Metal film resistor, 1/4W
R41 120R Metal film resistor, 1/4W
R42 100R Metal film resistor, 1/4W
LEDR 4k7 Metal film resistor, 1/4W LED current-limiting resistor. Adjust value to change LED brightness.
C1 100n Film capacitor, 7.2 x 2.5mm
C2 4.7uF Electrolytic capacitor, 4mm
C3 1n Film capacitor, 7.2 x 2.5mm
C4 22uF Electrolytic capacitor, 5mm
C5 220n Film capacitor, 7.2 x 2.5mm
C6 4.7uF Electrolytic capacitor, 4mm
C7 10n Film capacitor, 7.2 x 2.5mm
C8 47n Film capacitor, 7.2 x 2.5mm
C9 1n Film capacitor, 7.2 x 2.5mm
C10 47n Film capacitor, 7.2 x 2.5mm
C11 47n Film capacitor, 7.2 x 2.5mm
C12 1n Film capacitor, 7.2 x 2.5mm
C13 220n Film capacitor, 7.2 x 2.5mm
C14 2.2uF Film capacitor, 7.2 x 5mm
C15 1n Film capacitor, 7.2 x 2.5mm
C16 220n Film capacitor, 7.2 x 2.5mm
C17 2.2uF Film capacitor, 7.2 x 5mm
C18 10n Film capacitor, 7.2 x 2.5mm
C19 220n Film capacitor, 7.2 x 2.5mm
C20 22uF Electrolytic capacitor, 5mm
C21 22uF Electrolytic capacitor, 5mm
C22 100n MLCC capacitor, X7R Power supply filter capacitor.

CYGNUS DISTORTION/SUSTAINER 5
PARTS LIST, CONT.
PART VALUE TYPE NOTES
C23 220uF Electrolytic capacitor, 6.3mm Power supply filter capacitor.
C24 100uF Electrolytic capacitor, 6.3mm Power supply filter capacitor.
C25 220uF Electrolytic capacitor, 6.3mm Power supply filter capacitor.
D1 1N5817 Schottky diode, DO-41
D2 1N34A Germanium diode Exact part number is unimportant. Any germanium should work here.
D3 1N34A Germanium diode Exact part number is unimportant. Any germanium should work here.
D4 1N34A Germanium diode Exact part number is unimportant. Any germanium should work here.
D5 1N34A Germanium diode Exact part number is unimportant. Any germanium should work here.
Q1 2N5088 BJT transistor, NPN, TO-92 The original uses BC549C, but 2N5088 is the U.S. equivalent.
Q2 2N5088 BJT transistor, NPN, TO-92 The original uses BC549C, but 2N5088 is the U.S. equivalent.
Q3 2N5088 BJT transistor, NPN, TO-92 The original uses BC549C, but 2N5088 is the U.S. equivalent.
Q4 2N5088 BJT transistor, NPN, TO-92 The original uses BC549C, but 2N5088 is the U.S. equivalent.
Q5 2N5088 BJT transistor, NPN, TO-92 The original uses BC549C, but 2N5088 is the U.S. equivalent.
Q6 2N5088 BJT transistor, NPN, TO-92 The original uses BC549C, but 2N5088 is the U.S. equivalent.
SUST. 50kA 16mm right-angle PCB mount pot
TONE 25kB 16mm right-angle PCB mount pot
VOL. 10kA 16mm right-angle PCB mount pot
TB-BUF 4PDT slide Slide switch, 4PDT E-Switch EG4208 (4mm lever) or EG4208A (6mm lever)
IN 1/4" mono 1/4" phone jack, closed frame Switchcraft 111X 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.
FSW 3PDT Stomp switch, 3PDT
ENC 125B Enclosure, die-cast aluminum Can also use a Hammond 1590N1.

CYGNUS DISTORTION/SUSTAINER 6
BUILD NOTES
Transistor selection
The original G-2 uses BC549C transistors. The pinout on the Cygnus PCB is for the U.S. “E-B-C”
convention as used by the 2N3904 and 2N5088. The 2N5088 should operate identically to the BC549C,
but if you do want to use the original transistors, just note that the pinout is different. Typically they
would need to be rotated 180 degrees, but check the datasheet for your brand as they do vary.
Bypassing the true bypass / buffer switch
The E-Switch EG4208 slide switch used for the true bypass/buffer selector is available from Mouser
Electronics but may not be accessible to everyone. If you are unable to obtain it, you can hard-wire the
switch to either true bypass mode or buffered mode by soldering jumpers to the switch pads.
Tone modications
Cornish pedals are legendary for their reliability and the quality of their buffered bypass systems.
However, the G-2 in particular is known for having significantly more low-end than a standard Big Muff
circuit and this can sometimes be too much in a live setting depending on the mix.
Fortunately, you can get all of the benefits of the buffered bypass while also making the rest of the
circuit a little less bass-heavy and more similar to vintage Big Muffs. Here is a set of suggested mods:
• C1: 100n →27n
• C5: 220n →47n
• C9: 1n →470pF (MLCC)
• C12: 1n →470pF (MLCC)
• C13: 220n →100n
• C15: 1n →470pF (MLCC)
• C16: 220n →100n
• C19: 220n →100n
You can also compare the main part of the circuit (C8 onward in the schematic) with your favorite Muff
variant to tailor it even more to your liking. The tone control is the only part of the circuit that departs
from the classic Big Muff topology.
BUFFER BYPASS
TRUE BYPASS

SCHEMATIC
CYGNUS DISTORTION/SUSTAINER 7
GND
BUFFER OUT
FX GND
4k7
1N5817
220uF
VA
100n
GND GND GND GNDGND GND GNDGND GNDGND
39k
100k
470k
680R 15k
1k
8k2
100k
470k
680R 15k
8k2
100k
470k
100R 15k
390k100k
8k22k2
47n
1n
47n
47n
1n
220n
1n
220n
220n
2N3904 2N3904 2N3904
2N3904
50kA
10kA
Ge
Ge
Ge
Ge
39k
GND
22uF
620R
GND
22uF
25kB
10n
GND
100k
GND
100R
120R
100R
100uF 220uF
GND GND
VB VC VD
VD VD
VD
VDVC
10M
100n
1k
120k
120k
VB
200k
1n
4u7
2N3904
7k5
22uF
20k
51R
VB
GND GND GND
GND
1M
220n
1k
120k
68k150k
10n
4u7
2N3904
8k2
GND GND
GND
VC
VC
GND
2u2 2u2
LEDR
LED
D1
C23
B2
B3 B1
FSB
PCB IN
EFFECT OUT
FX GND
C22
R15
R16
R17
R19 R18
R20
R21
R22
R23
R25 R24
R26
R27
R28
R30 R29
R32R33
R34R35
C8
C9
C10
C11
C12
C13
C15
C16
C19
Q3 Q4 Q5
Q6
SUSTAIN
1
2
3
VOLUME
1
2
3
D2
D3
D4
D5
R37
C20
R36 C21
TONE
1
2
3
C18
R31
R40
R41
R42
C24 C25
R1
C1
R2
R3
R4R5
C3
C2
Q1
R6
C4
R7
R8
R9
C5
R10
R11
R12R13
C7
C6
Q2
R14
C14
C17
GND
GND
TO PCB IN
TO INPUT JACK
TO OUTPUT JACK
FROM BUFFER OUT
FROM EFFECT OUT
SWITCH POSITIONS SHOWN:
Slide switch (SW1 A-D): true bypass mode
Footswitch (FS A-C): effect bypass
91R
50k
A2
A3
A1 FSA
C2
C3
C1 FSC
SW1A
2
3
1
SW1B
5
6
4
SW1C
8
9
7
SW1D
11
12
10
R38
R39

CYGNUS DISTORTION/SUSTAINER 8
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
ø3/8” ø1/2”
0.385”
0.625” 0.625”
x: 0, y: -1.775
ø15/32”
x: -0.775, y: -1.775
ø5/16”
ø3/8”
125B
OUT
VOLUME SUSTAIN
TONE
FOOTSWITCHLED
DC IN
x: -0.65, y: +1.71 x: 0.65, y: +1.71
ø9/32” ø9/32”
x: 0, y: +0.66
ø9/32”
CENTER (0,0)
Note: On version 1 of the Cygnus, the LED is slightly misaligned from the drill template.
You’ll have to bend it back so it fits the drill hole. It will be fixed in the next revision of the PCB.

CYGNUS DISTORTION/SUSTAINER 9
ENCLOSURE LAYOUT
Enclosure is shown without jacks. See next page for jack layout and wiring.
125B

CYGNUS DISTORTION/SUSTAINER 10
WIRING DIAGRAM
125B
IN +VF.GND GND BUF FX
PCB
IN
FX
GND
+V +V JACK GND JACK
OUTIN
GND BUF
OUT
FX
OUT

CYGNUS DISTORTION/SUSTAINER 11
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
1.0.0 (2019-03-14)
Initial release.