The Bartolini HR-3.3AP/918 preamp harness makes a great upgrade to the output of your bass. This particular kit includes:
(1) Bartolini NTBT preamp module
(1) 250k Volume Potentiometer w/ Push/Pull Active-Passive Operation
(1) Dual 250k Potentiometer (for Dual Pickup Blending)
(1) Dual 50k Stacked Potentiometer w/ Center Detents (for Treble/Bass Stack)
(1) Set Of Plastic Knobs For Stacked Treble/Bass Pot
The HR-3.3AP/918 is pre-wired for 9 Volt Operation. For 18 Volt operation, simply install the additional 9 Volt battery harness (included). All pots and the output jack are pre-wired at Bartolini including grounding for all pots. Pots and Output jack include mounting nuts and washers. With the supplied instructions, installation is a breeze.
Dimensions: NTBT-918 Module = 1.75″L x 1.5″W x 0.5″D
Bass Control: +/- 16dB Centered at 30Hz.
Treble Control: +/- 15dB Centered at 10kHz.
9 or 18 Volt Operation (batteries not included), Additional 6dB with 18V Supply