The TWA Octoverdrive is an all-original overdrive pedal with a switchable Octavia-style circuit, built by TWA around a component most pedal makers never touch: obsolete selenium diodes. It runs two channels, called TREAT and TRICK. TREAT is what TWA describes as "a thick, harmonically rich tube-like drive," while TRICK layers a high-octave harmonic on top of the drive, in the spirit of the vintage Octavia fuzz. The maker says that unlike other Octavias, the Octoverdrive retains low end while also boosting output level1.
Guitar Pedal X reviewed it as the Octoverdrive Thick Overdrive + Octavia, calling it "a beautifully appointed and richly textured Octave Distortion" that combines selenium diode breakup with Thick Drive and Upper Octave modes2.
Two channels: TREAT and TRICK
The pedal's core idea is that the overdrive and the octave effect are two channels of one box, selected from the front panel. TWA describes them like this1:
- TREAT: a thick, harmonically rich tube-like drive. The maker says it "goes from creepy crunch to ghoulish gain with eerie ease," with what TWA calls the perfect degree of compression1.
- TRICK: adds a haunting, high-octave harmonic to the drive. TWA says that unlike other Octavias, this channel retains low end while also boosting output level1.
Guitar Pedal X names the two modes Thick Drive and Upper Octave, selected by a mode footswitch, and describes the result as a thick, dense overdrive with a piercing upper octave that lifts the whole sound and cuts through the mix2. Channel selection is footswitchable, with LED indicators, and a Jack O'Lantern LED display lights when the pedal is engaged3.
Selenium diodes: what they are and why they matter
Most overdrives clip the signal with silicon, germanium or LED diodes. The Octoverdrive clips with selenium rectifiers, a component type old enough that TWA calls them obsolete. The maker describes the pedal as a "100% Original and Unique Drive Circuit based around obsolete SELENIUM DIODES," and puts it more colorfully: the circuit is "cursed to clip for all eternity by a set of selenium rectifiers"3. Delicious Audio reported the same circuit description when the pedal was announced5.
TWA is candid about not being first here. The maker's page notes that Cusack's Screamer Fuzz Selenium, released in 2020, appears to win the award for first company to use selenium diodes to process audio, and that the Octoverdrive was developed without awareness of that pedal1. The page frames the design story as Jon Cusack's experiments with selenium diodes running parallel to Robert Derby's3.
Controls
The control set is shared across both channels, with a Drive knob that sets the amount of saturation for both5. Guitar Pedal X lists the full control complement2:
| Control | What it does |
|---|---|
| Drive | Sets the amount of saturation for both channels5 |
| Dry Blend | Blends clean signal with the drive1 |
| Level | Sets output volume2 |
| Bass, Mid, Treble | 3-band cut/boost EQ, labeled Lows, Mids and Highs by the maker3 |
| Mode footswitch | Selects Thick Drive or Upper Octave2 |
| Engage footswitch | Bypasses the pedal, mechanical true bypass3 |
The Dry Blend control is worth noting for anyone who has used an Octavia-style pedal before: because you can blend clean signal back in, the upper octave can sit under your core tone rather than replacing it. Delicious Audio described the Blend control as letting you reintegrate some clean tone for extra dynamics5.
Power, bypass and build
The Octoverdrive requires an external 9V DC power source; there is no battery option, so it needs a spot on a powered pedalboard3.
Bypass is mechanical true bypass, so the circuit drops entirely out of the signal chain when the pedal is off3. The pedal is made in the USA3.
Availability and price
TWA builds all of its pedals in limited batches, and the Octoverdrive is no exception: the maker states it is manufactured in a limited batch of 100 units3. Premier Guitar's launch coverage gave it a street price of $249 in October 20234; the maker's page also lists a price of £191.00 GBP3. When Guitar Pedal X reviewed it in March 2024, it was available for order on the TWA and Godlyke webstores2.
Players looking for other TWA drives can compare the TWA Source Code, an 18V Tube Screamer-style overdrive designed by Susumu Tamura, or the dual-channel TWA RZ-01 Chemical Z Roy Z signature overdrive.
What reviewers said
Guitar Pedal X's Stefan Karlsson reviewed the pedal in March 2024 and summed up the sound2:
"beautifully richly textured thick and dense overdrive with an additional piercing Upper Octave which lifts everything"2
Guitar Pedal X, March 20242
The same review noted the pedal's full control set and its two footswitchable modes, and reported it as available for order on the TWA and Godlyke webstores at the time2. Delicious Audio covered the pedal at launch in November 2023, highlighting the selenium diode circuit, the shared Drive control and the Blend control for reintegrating clean tone5.
Videos
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Godlyke Inc.
Godlyke Inc.
Questions
What are selenium diodes in the TWA Octoverdrive?
Selenium rectifiers are an obsolete older component that TWA uses as the clipping elements in the Octoverdrive's drive circuit. The maker describes the pedal as a 100% original and unique drive circuit based around obsolete selenium diodes, which gives the drive its own breakup character compared with the silicon or germanium diodes in most overdrives.
Is the TWA Octoverdrive a limited edition?
Yes. TWA states that, like all of its pedals, the Octoverdrive is manufactured in a limited batch of 100 units.
Who designed the TWA Octoverdrive?
The Octoverdrive was designed by Robert Derby of TWA. The maker's product page tells the story of Derby's work with selenium diodes, noting that Cusack's Screamer Fuzz Selenium, released in 2020, was developed separately and without TWA's awareness.
Is the TWA Octoverdrive true bypass?
Yes. The maker specifies mechanical true bypass switching, so the pedal's circuit is fully taken out of the signal path when it is disengaged.
Can the Octoverdrive run on a battery?
No. The Octoverdrive runs on 9V DC from an external power source only, so there is no battery option. You will need a 9V DC supply on your pedalboard to power it.
Sources (5)
- OCTOVERDRIVE™, Godlyke Distributing, Inc.
- Guitar Pedal X, Guitar Pedal X, 2024-03-27
- OCTOVERDRIVE™, Godlyke Distributing, Inc.
- TWA Releases Octoverdrive Overdrive/Octavia, Premier Guitar, 2023-10-13
- New Pedal: TWA Octoverdrive, Delicious Audio, 2023-11-01
