Overdrive guitar effect from the Nine Series. The Maxon OD-9 is their all-analog version of the classic TS-9 Tube Screamer effect. It uses the same circuit as the OD808 and produces a sound that helped shape the history of Rock and Roll. The effect produces a warm, natural vintage tone of the lamp amplifiers and can react very smoothly to the strength of the input signal or to the dynamics of the game. It also offers more drive than the OD808. The OD-9 Pro Plus Overdrive is, of course, True Bypass, uses the NJM 4558D Op Amp chip, and is controlled by Drive, Tone, Level potentiometers and a Boost / Normal switch. It offers a wide, natural overdrive sound in Normal mode, or reduced treble and bass, and vice versa boosted mids in Boost mode. The effect is further equipped with one foot switch, LED, one 1/4 "Jack input and one 1/4" Jack output. It is powered by a 9V battery or AC adapter.