The Homebrew Electronics zPower Screamer is an overdrive pedal providing many different overdrive sounds.
It sounds best when ran thru the input of a tube amp. It is not meant to be run through an effects loop. Features true hardwire bypass.

Input-Instrument in. Unplug when not in use to conserve battery life.

Out-Out to amp

-9VDC jack-for use with -(Negative) center, 9VDC, filtered, and regulated power supply (not included).

Gain control-Varies the amount of overdrive.

Level control-Varies the amount of output. Capable of driving an amp in to saturation. Sounds best when ran a little above unity.
(Louder with the pedal on)

Tone control-Varies the amount of treble.

Boost-Provides approximately 10db of gain/volume boost.

On/Off-True bypass of effect. (Note: a small pop may occur when effect is switched on/off. This is normal and is a trait associated with true bypass.)

Diode Select: Left-Classic overdrive-tight and controlled

Center-More bass, gain and volume, slight compression.

Right-Very compressed with tube like sag, warm, sounds like a small tube amp about to explode, best for single notes.)