The SBK Series preamp works great with any instrument equipped with either passive magnetic or piezo transducer pickups. With a +/- 12dB  range for either two (treble/bass) or three (treble/middle/bass) bands of equalization, they are pre-wired and ready to install. Features include standard and concentric JS-KIE potentiometers and a proprietary balance potentiometer with aNO SOLDER terminal block for neck and bridge (N-GND-B) pickup connection.

The circuit board is only 25D X 30W mm so it takes up minimal cavity space however SBK preamps require a minimum cavity depth of 1 1/4". SBK-A models reduce the number of potentiometers by combining functions with a concentric or "stacked" potentiometer. Our top of the line SBK-3A and SBK-3AD add a Frequency Range Shift (sweep) control to emphasize the mid frequencies. Features include brass shaft potentiometers for smoother control and longer life and a pre wired TRS (tip/ring/sleeve) output jack.

Technical Specification
Treble: +/-12 dB at 4 kHz
Middle +/- 12dB at 800 Hz ~ Sweep: +/- 2dB at 2kHz (SBK-3A/AD)
Bass:+/-12 dB at 100 Hz

Input Impedance: 1Mohm
Balance: MN500K w/center detent
Current: 0.16 mA
Voltage range: 6 ~ 22 volt
Battery Requirement: 9V alkaline (battery life 1000+ hours)

The balance potentiometer can simply be removed for single pickup applications. Marked contacts on the circuit board (IN+/IN-) are used for direct pickup connection. As an example, the SBK-2A for a P style bass with (2) controls or SBK-3AD for a MM style humbucker bass with (3) controls. The passive balance potentiometer is a MN500K with center detent. All preamps can be upgraded to an 18V system (2-9V in series) for additional headroom.

We suggest using pickups with similar outputs, either magnetic or piezoelectric, but not both together since the balance (blend) function is passive. Also our preamps were designed for use and work best with passive pickups. Although active pickups can be used we believe a preamp'ed signal going into another preamp is overkill and creates the opportunity for low level noise especially during recording. Also most active pickups have a low impedance output and our preamp's are designed with a high impedance input.

SBK-2 (4 potentiometers) - Balance~Volume~Treble~Bass

SBK-2A (3 potentiometers) - Balance~Volume~Treble/Bass

SBK-3 (5 potentiometers) - Balance~Volume~Treble~Middle~Bass

SBK-3A (5 potentiometers) - Balance~Volume~Treble~Bass~Middle/Sweep

SBK-3AD (4 potentiometers) - Balance~Volume~Treble/Bass~Middle/Sweep


GUITAR FUEL Performance Products