Ground Control Audio Amaterasu
The Amaterasu is best used to bring back some brightness to dull or darker setups such as guitars with humbucker pickups or a bad tinnitus. You can just as well use the Amaterasu with single coils, of course, which will make your tone glassy as heck. All this trebly goodness will absolutely push your amp’s front end into incisive bliss and you will enjoy it.
In technical speak, it is a 26dB, mostly flat, gain circuit followed by an optional extra 12dB of treble gain at 3.2KHz.