![12ax7 tube preamp pedal](https://kourbisamps.com/wp-content/uploads/2022/07/one-armed-bandit-view-1-1024x681.jpeg)
CONTROLS
GAIN - Controls the gain level, from mild crunch to higher distortion sounds.
BASS - Controls the bottom end of your tone by adjusting the low frequencies.
MIDDLE - Adjusts middle frequencies, making them fatter sounding when increased.
TREBLE - Controls the high frequencies, making your tone brighter as you increase it.
VOLUME - In conjunction with the gain control, a variety of sounds can be achieved.
MASTER - Controls the output volume level.
MODE - 3-way switch that changes the gain structure and tone of the pedal in each position.
![](https://kourbisamps.com/wp-content/uploads/2022/07/plexi-oab-right-side.jpg)
SPECIAL FEATURES
On/off bright switch on the gain knob.
On/off power switch.
Ground/Lift switch helps to eliminate any ground loops.
![One Armed Bandit tube preamp pedal front](https://kourbisamps.com/wp-content/uploads/2022/07/one-armed-bandit-side-4-1024x726.jpg)
contour switch.
On/off mid-boost switch.