The Homebrew Electronics Gary Holt Doomsday Device is like a Homebrew Electronics Power Screamer with a few extra twists. The gain and output were increased slightly and a completely different Tone control was designed with a wider, more responsive range. That was just the start. The most lethal feature of the Doomsday Device is the Doomsday footswitch which allows the user to footswitch between the two Diode Select settings each yielding different overdrive characteristics. True bypass, 9 volt battery or DC adapter operation.