The ZVEX Super Duper Sunn Concert Bass Mod is a boost pedal with added distortion and low-end gain, built by modding the company's own Super Duper 2-in-1 to mimic the Sunn Concert Bass solid-state amp. It arrived in June 2018 as a Vexter Series pedal, ZVEX's printed-graphics line, and listed for $249 at launch1.
What it does
Where the regular Super Duper 2-in-1 carries two Super Hard On style boost channels, the Concert Bass Mod keeps one channel and adds a second, new circuit in its place. The red side is the boost, with the "Crackle Okay" knob for gain and the "Master" knob for volume. The yellow section is a new circuit that adds more crunch to your signal, with a bottom-heavy character suited to the Sunn Concert Bass sound the pedal is chasing1.
To get there, ZVEX increased the sub-sonic frequency response on the Super Duper circuit and changed transistors, which the company said was done to "give the instruments sharp teeth while still sounding organic"1.
The controls
| Control | Side | What it does |
|---|---|---|
| Crackle Okay | Red | Gain control1 |
| Master | Red | Volume control1 |
| Yellow section | Yellow | New circuit adding crunch and bottom-heavy gain1 |
From the Super Duper 2-in-1 to the Sunn Concert Bass Mod
The Super Duper 2-in-1 itself is built around two channels in the style of the Super Hard On, ZVEX's clean boost. On the second channel, a master volume control replaces the tie-down output resistor found in a standard Super Hard On, and ZVEX notes that this master volume lets you use the pedal as an overdrive or distortion with any input volume23. Circuit hobbyists tracing the pedal have also documented a DIY approach of adding clipping diodes before the master volume on an on-off-on switch, giving everything from clean boost to fuzzy drive3.
The Concert Bass Mod takes that platform and reshapes it: one channel instead of two, a new yellow crunch circuit, extended sub-sonic response and different transistors1. ZVEX has continued to build variants on the same parts set; the current Daniel Buettner Super Duper 2-in-1 J179 uses parts otherwise identical to the Super Duper 2-in-1 and lists at $459.00 as of October 20264.
The Concert Bass Mod was announced in June 2018 as a limited, modded take on the Super Duper 2-in-1, listed at $249 at the time1. The regular Super Duper 2-in-1 and its Vexter variant remain the starting point for the circuit.
Videos
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Questions
What is the ZVEX Super Duper Sunn Concert Bass Mod based on?
It is a modified version of ZVEX's own Super Duper 2-in-1 boost pedal, reworked to mimic the Sunn Concert Bass solid-state amp. ZVEX increased the sub-sonic frequency response and changed transistors, which the company said was done to give the instruments sharp teeth while still sounding organic.
How many channels does the Super Duper Sunn Concert Bass Mod have?
One. Unlike the regular Super Duper, which packs two Super Hard On channels, the Concert Bass Mod only has a single channel, on the red side of the pedal with the Crackle Okay gain knob and the Master volume knob.
How does it differ from the regular Super Duper?
The regular Super Duper 2-in-1 has two Super Hard On style channels; the Concert Bass Mod has one. The yellow section is a new circuit that adds crunch and bottom-heavy gain, and ZVEX increased the sub-sonic frequency response and changed transistors compared with the standard pedal.
How much does the Super Duper Sunn Concert Bass Mod cost?
Guitar.com reported at its 2018 launch that the Super Duper Sunn Concert Bass Mod listed for $249. For comparison, ZVEX's current Daniel Buettner Super Duper 2-in-1 J179, which uses parts otherwise identical to the Super Duper 2-in-1, lists at $459.00 as of October 2026.
Sources (4)
- ZVEX launches new Super Duper 2-in-1 mod, Guitar.com, 2018-06-25
- Super Duper 2-in-1, ZVEX Effects (www.zvex.com)
- Guitar FX Layouts: ZVex Super Duper 2 in 1, Guitar FX Layouts (tagboardeffects.blogspot.com), 2016-09-13
- Daniel Buettner Super Duper 2-in-1, ZVEX Effects (www.zvex.com)
