The wide format Prefix Plus-T from Fishman is a preamp system designed to offer simple and versatile controls in a compact housing for instruments such as acoustic guitars and basses. The system includes the preamp unit, a Fishman Switchjack stereo 1/4" endpin jack, and a Fishman Acoustic Matrix pickup. The Prefix Plus-T also delivers a built-in tuner with LED display.

Equalization is handled via 3-band EQ controls (Bass, Contour, and Treble). The frequency of the Contour band can be varied from 250 Hz to 3 kHz. The Brilliance knob provides additional high-frequency tone shaping. The Volume control can be used to make up for any level changes incurred by drastic equalization. Combat feedback problems, common in live performance scenarios, by adjusting the Notch control. When mixing signals from pickups and microphones together, use the Phase switch to maintain phase coherency.

The Prefix Plus-T is powered via a single 9V battery (available separately). A convenient low-battery LED indicator lights up when the battery is nearing the end of its life, which extends up to 150 hours. Battery replacement is easy due to the pivot design of the preamp’s control panel.