OC-2
The Boss OC-2 Octave pedal uses the existing note going through it to generate 2 more notes: one octave, and two octaves down, respectively. The first version, released in 1982 was titled "Octaver" and was enameled in a reddish-brown color. As the circuit was updated, note tracking improved, and parts substitutions were made, the OC-2 was renamed the "Octave", and the paint scheme was changed the more familiar metal-flake brown.
The Boss OC-2 Octave is no longer being made.
- Thermionic Studios has two (2) OC-2s available for rental.
Controls
- Knob 1 - "Oct2": Sets the volume level for the signal two octaves lower than the dry signal. Turning the knob clockwise increases the volume.
- Knob 2 - "Direct Level": Sets the volume level for the dry signal. Turning the knob clockwise increases the volume.
- Knob 3 - "Oct1": Sets the volume level for the signal one octave lower than the dry signal. Turning the knob clockwise increases the volume.
- Footswitch 1 - "On/Off": Toggles the pedal between active ("on"), or bypassed ("off").
Bypass:Buffered
Like all Boss pedals, the OC-2 has a buffered bypass.
General Information
This Boss pedal, is like most other octave pedals that came out in the 1980s and is best played one note at a time. It's typically used either to thicken melody runs, or on solos. Because the OC-2 was not created as a polyphonic pedal, if more than one note is played, the note tracking circuitry will not be able to keep up. This tends to create sounds that are more like a cacophony than multi-octave chords being played; of course, this may be the sound you're looking for.
Eddie Van Halen used a rackmount Eventide Harmonizer for the outro to Fair Warning's "Unchained" (1981). The OC-2 makes a good (and far more portable) substitute for the Eventide.
Subsequent Boss Octave pedals include:
- OC-3 Super Octave
Pedal Manual
Phase Inversion: No
From our examination of the schematic below, the OC-2 does not appear to invert phase on the output as compared with the signal that goes into the pedal.
If you look at the schematic, you can see that there are a number of amplification stages after Q1 that are taken up by 3 IR9022 opamps. However, you'll also see that the output at pins 1, and 7 for all of J, I , H, G, F, and E are connected and feed back into pins 2 and 5, respectively. This appears to us to be negative feedback, lowering the total amplification, but adding signal stability. If anyone is more knowledgeable about this, we'd love to be updated for the most accurate explanation possible.
The other thing to note is that the 4013 output gets split, with part of the one-octave down signal directed into the 4027 chip. Afterwards, it should be fairly easy to track the Octave1 and Octave2 signals running parallel through similar circuit architecture.
| Schematic ID | Electronic Part | Action | Phase State |
|---|---|---|---|
| Q1 | 2SK30A | Does Not Invert | Not Inverted |
| IC-J | IR9022 | Does Not Invert | Not Inverted |
| IC-I | IR9022 | Does Not Invert | Not Inverted |
| IC-H | IR9022 | Does Not Invert | Not Inverted |
| IC-G | IR9022 | Does Not Invert | Not Inverted |
| IC-F | IR9022 | Does Not Invert | Not Inverted |
| IC-E | IR9022 | Does Not Invert | Not Inverted |
| Q2 | 2SK30A | Does Not Invert | Not Inverted |
| IC-B | IR9022 | Does Not Invert | Not Inverted |
| IC-C | IR9022 | Does Not Invert | Not Inverted |
| Q3 | 2SK30A | Does Not Invert | Not Inverted |
| IC-A | IR9022 | Does Not Invert | Not Inverted |
| IC-D | IR9022 | Does Not Invert | Not Inverted |
| Q4 | "NPN" | Does Not Invert | Not Inverted |
Schematic
Artists
- Additional Sources
