Sadowsky Bass Onboard Preamp 4-Knob

SADOWSKI Onboard Bass Preamp 4-Knob is a completely prewired system offering the same controls and preamp as all Sadowsky Basses : volume, pan, bass boost, treble boost, and vintage tone control.
The preamp can be installed with the included control plate or mounted through a rear control cavity in either a 4 in line or diamond pattern.
Pickups attach via solderless connectors at the pan pot.
Installation requires a side jack and a battery compartment.

VTC (Vintage Tone Control) is a passive control in which 10 is flat and as you roll it down it knocks off a broad swath of high end to give you a warmer tone.
Although the control is passive, it functions with the bass in either active or passive mode.
A little rolled off knocks off a lot of string noise. All the way rolled off, it gives you a lot of that "motown/flatwound" sound".