BARTOLINI NTMB Pot, with Jack This is an onboard preamp for bass guitars. Functionality confirmed. Pots are Alpha, jack is Switchcraft. Volume pot has some scratchiness around the 1-3 range. However, it's not very noticeable, so it should be usable as is. EQ pots have no scratchiness, and the jack has no scratchiness. Mid switch also confirmed to be working. Some adhesive residue remains on the cover. BARTOLINI 3-band EQ preamp module for bass guitars. Features a gain trim (output level adjustment) model. Supports 9V or 18V. ■ Bass preamp ■ 3-band EQ ・Bass: +/-15dB @30Hz ・Mid: +/-13dB @250Hz ・Treble: +/-18dB @10kHz ■ MID can be switched between 250Hz, 500Hz, and 800Hz