Fishman Presys Plus Preamp Narrow Or Wide. The Presys+ Onboard Preamp System is designed and built to offer maximum control, performance and quality in a small, unobtrusive format. The compact sophisticated Presys+ system features Volume, Bass, Mid and Treble controls, a Phase switch, and a built-in tuner with LED display. The Presys+ preamp also includes a pre-wired Fishman Sonicore pickup for solder-free, plug and play installation, a low battery indicator, low profile control knobs and a unique pivot design for easy access to the battery compartment.