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CORVUS DISTORTION / SUSTAINER

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PROJECT NAME

CORVUS

BASED ON

EFFECT TYPE

PROJECT SUMMARY

DOCUMENT VERSION

EHX Big Muff Pi (1978 Op-Amp)

The 1978 redesign of the classic Big Muff Pi, using op-amps instead of transistors. Famously used by 
Billy Corgan on the Smashing Pumpkins album Siamese Dream.

Fuzz / Distortion

1.0.1 (2021-04-20)

Actual size is 2.3” x 1.86” (main board) and 1.78” x 0.87” (bypass board).

BUILD DIFFICULTY

Easy

Summary of Contents for 2207

Page 1: ...HX Big Muff Pi 1978 Op Amp The 1978 redesign of the classic Big Muff Pi using op amps instead of transistors Famously used by Billy Corgan on the Smashing Pumpkins album Siamese Dream Fuzz Distortion...

Page 2: ...f formally adopting its formerly unofficial name the Op Amp Big Muff Pi The Corvus is based on the 1978 revision of the Big Muff which added a Tone Bypass switch As inferred by the name this switch fu...

Page 3: ...OMIT 47R in stock version See build notes R9 8k2 Metal film resistor 1 4W R10 470k Metal film resistor 1 4W R11 5k6 Metal film resistor 1 4W R12 1k2 Metal film resistor 1 4W R13 47k Metal film resist...

Page 4: ...4 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 IC1 RC4558P Operational amplifier DIP8 IC1 S DIP 8 socket IC so...

Page 5: ...to running it full up and then cutting back the level afterward So the Corvus includes a modification suggested by Analogguru that accomplishes this C4 is added as a DC blocking capacitor and the Sus...

Page 6: ...uF GND 10uF GND 1uF 8k2 GND 470k 330pF 10kB 1uF 100n 5k6 1k2 GND 120n GND 150n 47k 47k GND 100k GND VB VC 10uF VA GND VB VC OMIT 47R VA GND IN OUT RPD D1 C14 C15 SUSTAIN 1 2 3 VOLUME 1 2 3 R17 C1 R1 2...

Page 7: ...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 L...

Page 8: ...CORVUS DISTORTION SUSTAINER 8 ENCLOSURE LAYOUT Enclosure is shown without jacks See next page for jack layout and wiring 125B...

Page 9: ...CORVUS DISTORTION SUSTAINER 9 WIRING DIAGRAM 125B IN V GND N C N C OUT PCB IN GND V V JACK GND JACK OUT IN GND GND PCB OUT...

Page 10: ...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...

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