Akashic Guitar effects PCB lookup
SUSTAINTONEVOLUME

125B · 3 knobs

Aion FX

CygnusDistortion / Sustainer

Based on the Cornish P-2 / G-2

Category
Fuzz· Distortion/Sustainer, Fuzz
Controls
Sustain · Tone · Volume
Difficulty
Intermediate
Price
$12.50in stock

From the vendor

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.

The Cygnus Distortion/Sustainer is adapted from the Pete Cornish P-2 and G-2, two Big Muff-based pedals that share a PCB but with several part differences to distinguish them.

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 P-2 was originally designed for David Gilmour, while the G-2 was developed with Lou Reed.

Inside, the circuit is a basic Big Muff with a few changes such as a simplified hi-cut tone control and the famous class-A transistor buffer design. The P-2 is similar to a Ram’s Head Muff, while the G-2 was designed to be much lower gain with a drastically different EQ as well as germanium clipping diodes. In fact, until the G-2 it was traced in 2009, people had no idea it was a Muff derivative. The P-2 was traced by Aion FX in 2023.

The Cygnus is a faithful reproduction of the P-2 and G-2 circuits. The kit is for the P-2 version, but the parts list in the PCB build document includes both variants. The default is the P-2 circuit, while each G-2 change is listed in the “Notes” column.

We’ve made one major addition in our project: 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.

Note: The PCB-only version of this project uses a type of capacitor that has been temporarily discontinued by WIMA. Please see our news article about the issue and the substitution spreadsheet for project-specific recommendations. We are stocking a limited supply in the mean time. The build document has not yet been updated to reflect this. It does not impact the kits.

Schematic

The schematic is in the vendor's build document, page 8. Open the build document. No KiCad fragment has been drawn for this circuit yet.

Parts list 88 rows

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RefValueNormalizedTypeNotes
Resistors 43
R110M10MMetal film resistor, 1/4W
R21k1kMetal film resistor, 1/4W
R3120k120kMetal film resistor, 1/4W
R4120k120kMetal film resistor, 1/4W
R5200k200kMetal film resistor, 1/4W
R67k57.5kMetal film resistor, 1/4W
R710k10kMetal film resistor, 1/4W
R851R51Metal film resistor, 1/4W
R91M1MMetal film resistor, 1/4W
R101k1kMetal film resistor, 1/4W
R11120k120kMetal film resistor, 1/4W
R1268k68kMetal film resistor, 1/4W
R13150k150kMetal film resistor, 1/4W
R1410k10kMetal film resistor, 1/4WSome early G-2 units used 8k2, but most used 10k, the same as the P-2.
R1539k39kMetal film resistor, 1/4W
R16100k100kMetal film resistor, 1/4W
R17470k470kMetal film resistor, 1/4W
R1815k15kMetal film resistor, 1/4W
R19100R100Metal film resistor, 1/4WEarly G-2 uses 680R. Later G-2 changed to 100R, the same as the P-2.
R20100R100Metal film resistor, 1/4WEarly G-2 uses 1k with 50kA sustain pot. Later G-2 uses 2k and 100kA.
R218k28.2kMetal film resistor, 1/4W
R22100k100kMetal film resistor, 1/4W
R23470k470kMetal film resistor, 1/4W
R2415k15kMetal film resistor, 1/4W
R25100R100Metal film resistor, 1/4WEarly G-2 uses 680R. Later G-2 changed to 100R, the same as the P-2.
R268k28.2kMetal film resistor, 1/4WP-2 and early G-2. Later G-2 changed to 3k3.
R27100k100kMetal film resistor, 1/4W
R28470k470kMetal film resistor, 1/4W
R2915k15kMetal film resistor, 1/4W
R30100R100Metal film resistor, 1/4W
R31100k100kMetal film resistor, 1/4W
R32390k390kMetal film resistor, 1/4W
R33100k100kMetal film resistor, 1/4W
R3410k10kMetal film resistor, 1/4WEarly G-2 uses 8k2. Later G-2 changed to 10k, the same as the P-2.
R352k22.2kMetal film resistor, 1/4W
R361k21.2kMetal film resistor, 1/4WEarly G-2 uses 620R. Later G-2 uses 1k8. Unpopulated in some P-2 units.
R3739k39kMetal film resistor, 1/4W
R3891R91Metal film resistor, 1/4W
R3951k51kMetal film resistor, 1/4W
R40100R100Metal film resistor, 1/4W
R41120R120Metal film resistor, 1/4W
R42100R100Metal film resistor, 1/4W
LEDR10k10kMetal film resistor, 1/4WLED current-limiting resistor. Adjust value to change LED brightness.
Capacitors 25
C1100n100nFilm capacitor, 7.2 x 2.5mm
C24.7uF4.7uElectrolytic capacitor, 4mm
C31n1nFilm capacitor, 7.2 x 2.5mm
C422uF22uElectrolytic capacitor, 5mm
C5220n220nFilm capacitor, 7.2 x 2.5mm
C64.7uF4.7uElectrolytic capacitor, 4mm
C710n10nFilm capacitor, 7.2 x 2.5mm
C847n47nFilm capacitor, 7.2 x 2.5mm
C9470pF470pMLCC capacitor, NP0/C0GEarly G-2 used 1n film or 470pF. Later G-2 uses 100pF. P-2 uses 470pF.
C1047n47nFilm capacitor, 7.2 x 2.5mm
C1147n47nFilm capacitor, 7.2 x 2.5mm
C12470pF470pMLCC capacitor, NP0/C0GSome early G-2 units used 1n film. P-2 and later G-2 are 470pF.
C13220n220nFilm capacitor, 7.2 x 2.5mm
C142.2uF2.2uFilm capacitor, 7.2 x 5mmOriginally 4.7uF electrolytic. Later G-2 uses 220n. See build notes.
C15470pF470pMLCC capacitor, NP0/C0GSome early G-2 units used 1n film. P-2 and later G-2 are 470pF.
C16220n220nFilm capacitor, 7.2 x 2.5mm
C172.2uF2.2uFilm capacitor, 7.2 x 5mmOriginally 4.7uF electrolytic. See build notes.
C1810n10nFilm capacitor, 7.2 x 2.5mm
C19220n220nFilm capacitor, 7.2 x 2.5mm
C2122uF22uElectrolytic capacitor, 5mm
C22100n100nMLCC capacitor, X7RPower supply filter capacitor.
C23220uF220uElectrolytic capacitor, 6.3mmPower supply filter capacitor.
C24100uF100uElectrolytic capacitor, 6.3mmPower supply filter capacitor.
C25220uF220uElectrolytic capacitor, 6.3mmPower supply filter capacitor.
C2610n10nFilm capacitor, 7.2 x 2.5mmP-2 only (but left empty in some). Omit for G-2. See build notes.
Diodes 5
D11N58171N5817Schottky diode, DO-41
D21N9141N914Fast-switching diode, DO-35G-2 uses germanium (e.g. 1N34A). See build notes.
D31N9141N914Fast-switching diode, DO-35G-2 uses germanium (e.g. 1N34A). See build notes.
D41N9141N914Fast-switching diode, DO-35Early G-2 used germanium. Later G-2 used BAT81S.
D51N9141N914Fast-switching diode, DO-35Early G-2 used germanium. Later G-2 used BAT81S.
Transistors 6
Q1BC550CBC550CBJT transistor, NPN, TO-92G-2 uses BC549C.
Q2BC550CBC550CBJT transistor, NPN, TO-92G-2 uses BC549C.
Q3BC550CBC550CBJT transistor, NPN, TO-92G-2 uses BC549C.
Q4BC550CBC550CBJT transistor, NPN, TO-92G-2 uses BC549C.
Q5BC550CBC550CBJT transistor, NPN, TO-92G-2 uses BC549C.
Q6BC550CBC550CBJT transistor, NPN, TO-92G-2 uses BC549C.
Potentiometers 3
SUSTAIN100kAA100k16mm right-angle PCB mount potEarly G-2 used 47kA (50kA equivalent), later changed to 100kA.
TONE25kBB25k16mm right-angle PCB mount pot
VOLUME10kAA10k16mm right-angle PCB mount pot
Switches 2
TB-BUF4PDT slide4PDT SLIDESlide switch, 4PDTE-Switch EG4208 (4mm lever) or EG4208A (6mm lever)
FSW3PDT3PDTStomp switch, 3PDTAvailable from Aion FX.
Jacks & sockets 3
IN1/4" mono1/4" MONO1/4" phone jack, closed frameSwitchcraft 111X or equivalent.
OUT1/4" mono1/4" MONO1/4" phone jack, closed frameSwitchcraft 111X or equivalent.
DC2.1mm2.1MMDC jack, 2.1mm panel mountLumberg NEB/J 21 C or equivalent.
Hardware 1
ENC125B125BEnclosure, die-cast aluminumCan also use a Hammond 1590N1.