The Maelstrom Bass Drive takes inspiration from the Darkglass Microtubes B3K, a popular CMOS-based bass drive circuit. The B3K was originally developed by Douglas Castro and was based on the Microtubes 2K, which he shared on the DIYStompboxes forum in 2008. After moving to Finland and starting Darkglass Electronics, Castro continued to refine the design, resulting in the Microtubes B3K becoming Darkglass’s first commercial product.

While the original Microtubes 2K drew inspiration from the EHX Hot Tubes and other CMOS-based designs, the B3K had evolved into a unique circuit. It utilizes a single overdriven CMOS stage for its clipping tone, which sets it apart from other similar circuits that use cascaded inverters.

The Vintage Microtubes, released in 2013, is essentially the same circuit as the B3K but with some modifications. It removes the two toggle switches found on the B3K and adds a new control called “Era,” which is a midrange tone control.

The Maelstrom Bass Drive is a direct adaptation of the Microtubes B3K, featuring the Era control from the Vintage Microtubes (renamed to “Tone” on the kit enclosure). When the Era control is turned down, the Maelstrom is identical to the standard B3K. The PCB build documentation also includes part substitutions to build it to full Vintage Microtubes specifications if desired.

Summary created by AI from the original source.