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Gaia Mk. I Preamp Drive

Based On
Catalinbread® CB30
Effect Type
Overdrive / Amp Emulation
Build Difficulty
Project Summary
An adaptation of the Vox® AC30, a legendary British amplifier responsible for the signature guitar tones of the 60s and 70s. It uses cascaded mu-amp stages in place of tubes for amp-like tone in a small box.
Gaia Mk. I Preamp Drive printed circuit board

Printed Circuit Board

What's included?
PCB only. Build instructions and parts list can be viewed or downloaded from this page.


In stock

Complete Kit

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Kits are developed based on interest, so if you’d like to see one for this project, let us know.
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Project overview

The Gaia Preamp Drive Mk. I is an adaptation of the Catalinbread CB30, their pedal emulation of a Vox® AC30 amplifier.

The CB30 was originally released in 2011. Curiously, there were two different versions, although there’s no official record from Catalinbread of a V1 and V2. Aion FX traced a version with eight JFETs in 2021, and the low serial number indicates it was an early unit. However, the community traced one during the first month it was released (June 2011) and the photos show a completely different PCB layout and a circuit with only five JFETs.

The eight-JFET version seems to be more common based on reviewing archived Reverb listing photos. Other than the one traced on FSB, we haven’t seen any other five-JFET versions. The most likely explanation is that the five-JFET version was a very short-lived initial run and it was quickly redesigned within a few months of release, but without any official announcement or any cosmetic changes that might denote the internal change. Since the CB30 was never a flagship pedal for Catalinbread like the Dirty Little Secret, the gear community never noticed that there were actually two versions and nobody ever asked Catalinbread for the real story.

In 2012, the CB30 was incorporated into the Galileo, a dual pedal containing a Rangemaster-derived Naga Viper treble booster in the same enclosure, emulating Brian May’s treble-boosted AC30 guitar tone. In 2014, the second version of the Galileo was released, this time a single pedal that internally contained the Naga Viper and a redesigned CB30 using MPF4393 JFETs, but with only three knobs and one footswitch. This is available from Aion FX as the Gaia Mk. II.

The standalone CB30 was later reissued in fall 2020 as a Sweetwater exclusive. It’s not known if this version incorporates any redesigned circuitry from the original 2011 version or if it’s just the artwork that is different.

The CB30 used 2N5457 JFETs, which are no longer available in through-hole format. Extra pads have been provided if you want to use surface-mount JFETs (part number MMBF5457), which are still in production and perform identically to those used in Catalinbread pedals. Aion FX also offers pre-soldered MMBF5457s on adapter boards if you find surface-mount parts intimidating. See build notes for more details.

The Gaia Mk. I can be run at 18V for increased volume and clarity, but it is not compatible with the 18V Voltage Doubler / Bypass module due to the larger format of the PCB.