Our Lab Series #28 consist of two modification to the original HM-2 Schematic.
The #28A is a "volume only" version. With everything at 10 and only a knob for the volume control.
The #28B version is a modded version with a "Clean bypass" toggle switch to bypass the distortion and diodes stage and get a clean boost for your high gain amp. There's a hype around that mod in the community and our lab #28B is our prototype. Have a look at our TorchX if you want the production model.
The production model of the #28B is our TorchX with the mods : TorchX