Another 37+ Fishman Equalizer For Acoustic Guitar. Bass and treble controls for enhanced tone shaping. Fixed the hinge problem with shrink tubing (you'll need to unscrew the bottom cover first), and a small strip of gaffing tape on the lock. Get the guaranteed best price on guitar preamps like the fishman tonedeq acoustic guitar preamp eq at musician's friend. Passive acoustic guitar pickup for sound hole magnetic preamp eq equalizer tuner.