The Rocktron O.D.B (Overdrive Dynamic Blues) is an overdrive pedal from Rocktron's Boutique Series of stompboxes. Its distinguishing feature is a pair of switches for the circuit's germanium diodes, which let you individually engage clipping on the positive and negative portions of the overdrive circuit. With both diodes on you get symmetrical clipping; with one on and the other off you get asymmetrical soft clipping, a choice that changes how the drive breaks up1.
Controls and clipping modes
The O.D.B breaks from the ubiquitous three-knob Tube Screamer-style overdrive design. Instead it uses two concentric knobs: one pair controls tone and output, the other drive and dynamic range, the latter described as soft-knee compression1.
| Control | What it does |
|---|---|
| Tone/Output knob (concentric) | Tone and output level1 |
| Drive/Dynamic Range knob (concentric) | Drive amount and dynamic range, with soft-knee compression1 |
| Germanium diode switch 1 | Engages clipping on the positive portion of the circuit1 |
| Germanium diode switch 2 | Engages clipping on the negative portion of the circuit1 |
The two diode switches give three practical settings: both on for symmetrical clipping, either single switch on for asymmetrical clipping, and the choice between them as a tone-shaping tool in its own right1.
What reviewers said
Guitar World's review of the Boutique Series stompboxes was taken with the diode switches: "Even cooler are the pair of switches for the circuit's germanium diodes, which allow users to individually engage clipping"1.
On the sound with the diodes set to asymmetrical soft clipping, the reviewer wrote: "its tone is downright dirty, funky and nas-tay. The pedal produces a hotter version of overdrive reminiscent of [Billy Gibbons' bluesiest edge-of-distortion moments" and described an "Octavia-style fuzz with the germanium diodes dialed in to asymmetrical soft clipping"1.
For context on where the O.D.B sits, see the site's pages on Overdrive Pedals, Distortion Pedals, Fuzz Pedals and the Boss SD-1 vs Ibanez TS9 Tube Screamer comparison, the latter being the three-knob design the O.D.B departs from1.
Videos
I Love Blues Guitar
ON Play Guitar
Tone Works
Questions
What makes the Rocktron O.D.B different from other overdrives?
It breaks from the common three-knob Tube Screamer-style overdrive layout with two concentric knobs, and it adds a pair of switches for the circuit's germanium diodes. Each switch engages clipping on either the positive or negative portion of the signal, so you can run symmetrical clipping with both on or asymmetrical clipping with one on and one off, which changes the character of the drive.
What does asymmetrical clipping sound like on the O.D.B?
Guitar World's reviewer found that with the germanium diodes set to asymmetrical soft clipping, the pedal produced an Octavia-style fuzz tone, alongside a hotter overdrive reminiscent of Billy Gibbons' bluesiest edge-of-distortion moments. With both diodes engaged, the pedal runs in symmetrical clipping mode.
Sources (1)
- Review: Rocktron Boutique Series Stomp Boxes, Guitar World, 2013-06-17
