125B · 3 knobs
OceanidOptical Compressor
Based on the Cornish OC-1
- Category
- Compressor
- Controls
- Compression · Blend · Volume
- Difficulty
- Intermediate
- Price
- $12.50in stock
From the vendor
Pete Cornish's original optical compressor design features a clean blend and a complex side-chain for envelope detection along with his legendary input buffer.
The Oceanid Optical Compressor is adapted from the Pete Cornish OC-1 Optical Compressor, originally released in 2014 and traced by Aion FX in 2019.
Cornish pedals are 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 such as David Gilmour and Brian May. The OC-1 in particular names Paul McCartney as an owner.
The OC-1 is an original circuit, and it bears the marks of careful design, without any clear comparisons to anything else out there. It uses the LDR-to-ground method of volume reduction as seen in early optical limiter circuits like the LA2A, but the methods of generating the LED control voltage from the envelope are unique, and the clean-blend circuit is a little more complex than what you normally see.
The Oceanid is a faithful reproduction of the OC-1 circuit, but with one major addition: an internal slide switch allowing the pedal to be used in true-bypass mode instead of buffered bypass. As with the Klon KTR, the buffered mode is “almost always better”, but with this feature, you can determine for yourself.
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 95 rows
Report a wrong parse| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 45 | ||||
| R1 | 10M | 10M | Metal film resistor, 1/4W | |
| R2 | 1k | 1k | Metal film resistor, 1/4W | |
| R3 | 120k | 120k | Metal film resistor, 1/4W | |
| R4 | 120k | 120k | Metal film resistor, 1/4W | |
| R5 | 200k | 200k | Metal film resistor, 1/4W | |
| R6 | 7k5 | 7.5k | Metal film resistor, 1/4W | |
| R7 | 10k | 10k | Metal film resistor, 1/4W | |
| R8 | 51R | 51 | Metal film resistor, 1/4W | |
| R9 | 1M | 1M | Metal film resistor, 1/4W | |
| R10 | 1M | 1M | Metal film resistor, 1/4W | |
| R11 | 10k | 10k | Metal film resistor, 1/4W | |
| R12 | 10k | 10k | Metal film resistor, 1/4W | |
| R13 | 10k | 10k | Metal film resistor, 1/4W | |
| R14 | 1M | 1M | Metal film resistor, 1/4W | |
| R15 | 8k2 | 8.2k | Metal film resistor, 1/4W | |
| R16 | 91R | 91 | Metal film resistor, 1/4W | |
| R17 | 10k | 10k | Metal film resistor, 1/4W | |
| R18 | 10k | 10k | Metal film resistor, 1/4W | |
| R19 | 51k | 51k | Metal film resistor, 1/4W | |
| R20 | 18k | 18k | Metal film resistor, 1/4W | |
| R21 | 10k | 10k | Metal film resistor, 1/4W | |
| R22 | 91R | 91 | Metal film resistor, 1/4W | |
| R23 | 1M | 1M | Metal film resistor, 1/4W | |
| R24 | 2k2 | 2.2k | Metal film resistor, 1/4W | |
| R25 | 30k | 30k | Metal film resistor, 1/4W | |
| R26 | 91k | 91k | Metal film resistor, 1/4W | |
| R27 | 10k | 10k | Metal film resistor, 1/4W | |
| R28 | 91k | 91k | Metal film resistor, 1/4W | |
| R29 | 100k | 100k | Metal film resistor, 1/4W | |
| R30 | 100R | 100 | Metal film resistor, 1/4W | |
| R31 | 1k | 1k | Metal film resistor, 1/4W | |
| R32 | 15k | 15k | Metal film resistor, 1/4W | |
| R33 | 10k | 10k | Metal film resistor, 1/4W | |
| R34 | 100k | 100k | Metal film resistor, 1/4W | |
| R35 | 47k | 47k | Metal film resistor, 1/4W | |
| R36 | 3k3 | 3.3k | Metal film resistor, 1/4W | |
| R37 | 1k | 1k | Metal film resistor, 1/4W | |
| R38 | 91R | 91 | Metal film resistor, 1/4W | |
| R39 | 51k | 51k | Metal film resistor, 1/4W | |
| R40 | 100R | 100 | Metal film resistor, 1/4W | |
| R41 | 8k2 | 8.2k | Metal film resistor, 1/4W | |
| R42 | 10k | 10k | Metal film resistor, 1/4W | |
| R43 | 100R | 100 | Metal film resistor, 1/4W | |
| R44 | 100R | 100 | Metal film resistor, 1/4W | |
| LEDR | 10k | 10k | Metal film resistor, 1/4W | LED current-limiting resistor. Adjust value to change LED brightness. |
| Capacitors 26 | ||||
| C1 | 100n | 100n | Film capacitor, 7.2 x 2.5mm | |
| C2 | 4.7uF | 4.7u | Electrolytic capacitor, 4mm | |
| C3 | 1n | 1n | Film capacitor, 7.2 x 2.5mm | |
| C4 | 22uF | 22u | Electrolytic capacitor, 5mm | |
| C5 | 100n | 100n | Film capacitor, 7.2 x 2.5mm | |
| C6 | 2.2uF | 2.2u | Electrolytic capacitor, 4mm | |
| C7 | 470pF | 470p | MLCC capacitor, NP0/C0G | |
| C8 | 22uF | 22u | Electrolytic capacitor, 5mm | |
| C9 | 100n | 100n | Film capacitor, 7.2 x 2.5mm | |
| C10 | 4.7uF | 4.7u | Electrolytic capacitor, 4mm | |
| C11 | 220pF | 220p | MLCC capacitor, NP0/C0G | |
| C12 | 470n | 470n | Film capacitor, 7.2 x 3mm | |
| C13 | 220pF | 220p | MLCC capacitor, NP0/C0G | |
| C14 | 470n | 470n | Film capacitor, 7.2 x 3mm | |
| C15 | 22uF | 22u | Electrolytic capacitor, 5mm | |
| C16 | 100n | 100n | Film capacitor, 7.2 x 2.5mm | |
| C17 | 2.2uF | 2.2u | Electrolytic capacitor, 4mm | |
| C18 | 150pF | 150p | MLCC capacitor, NP0/C0G | |
| C19 | 22uF | 22u | Electrolytic capacitor, 5mm | |
| C20 | 4.7uF | 4.7u | Electrolytic capacitor, 4mm | |
| C21 | 100n | 100n | MLCC capacitor, X7R | Power supply filter capacitor. |
| C22 | 100uF | 100u | Electrolytic capacitor, 6.3mm | Power supply filter capacitor. |
| C23 | 47uF | 47u | Electrolytic capacitor, 5mm | Voltage reference filter capacitor. |
| C24 | 220uF | 220u | Electrolytic capacitor, 6.3mm | Power supply filter capacitor. |
| C25 | 220n | 220n | MLCC capacitor, X7R | Power supply filter capacitor. |
| C26 | 220uF | 220u | Electrolytic capacitor, 6.3mm | Power supply filter capacitor. |
| Diodes 4 | ||||
| D1 | 1N5817 | 1N5817 | Schottky diode, DO-41 | |
| D2 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| D3 | 1N914 | 1N914 | Fast-switching diode, DO-35 | |
| Z1 | LM4040-5.0 | LM4040-5.0 | Voltage reference, TO-92 | Full part number is LM4040CIZ-5.0. See build notes for more info. |
| Transistors 2 | ||||
| Q1 | BC549C | BC549C | BJT transistor, NPN, TO-92 | Can use 2N5088 (rotate 180 degrees). |
| Q2 | BC550C | BC550C | BJT transistor, NPN, TO-92 | Can use 2N5088 (rotate 180 degrees). |
| ICs 4 | ||||
| IC1 | TL072 | TL072 | Operational amplifier, DIP8 | |
| IC2 | TL072 | TL072 | Operational amplifier, DIP8 | |
| IC3 | LM358N | LM358N | Operational amplifier, DIP8 | |
| IC4 | LM358N | LM358N | Operational amplifier, DIP8 | |
| Opto 1 | ||||
| VACT. | NSL-32 | NSL-32 | Vactrol/opto-isolator, NSL-32 | Make sure this is installed correctly. See build notes. |
| Potentiometers 3 | ||||
| COMP. | 10kC | C10k | 16mm right-angle PCB mount pot | |
| BLEND | 25kB | B25k | 16mm right-angle PCB mount pot | |
| VOL. | 100kA | A100k | 16mm right-angle PCB mount pot | |
| Trimmers 1 | ||||
| BIAS | 20k | 20k | Trimmer, 10%, 1/4” | Bourns 3362P or equivalent |
| Switches 1 | ||||
| FSW | 3PDT | 3PDT | Stomp switch, 3PDT | Available from Aion FX. |
| Jacks & sockets 7 | ||||
| IC1-S | DIP-8 socket | DIP-8 SOCKET | IC socket, DIP-8 | |
| IC2-S | DIP-8 socket | DIP-8 SOCKET | IC socket, DIP-8 | |
| IC3-S | DIP-8 socket | DIP-8 SOCKET | IC socket, DIP-8 | |
| IC4-S | DIP-8 socket | DIP-8 SOCKET | IC socket, DIP-8 | |
| IN | 1/4" mono | 1/4" MONO | 1/4" phone jack, closed frame | Switchcraft 111X or equivalent. |
| OUT | 1/4" mono | 1/4" MONO | 1/4" phone jack, closed frame | Switchcraft 111X or equivalent. |
| DC | 2.1mm | 2.1MM | DC jack, 2.1mm panel mount | Lumberg NEB/J 21 C or equivalent. |
| Hardware 1 | ||||
| ENC | 125B | 125B | Enclosure, die-cast aluminum | Can also use a Hammond 1590N1. |