1988-1990 Yamaha PB1 Bass Preamp.
Used, so has signs of wear but works perfectly.
This is the write-up on the PB1 as found in the original manual
The PB1 Component Bass Preamplifier gives the musician the unique opportunity to control his bass guitar sound completely. You'll begin to see a whole new range of expressive possibilities in your instrument.
The PB1 offers standard volume, treble, middle and bass controls - plus a full parametric equalizer system and independent variable high and low-pass filters that permit a broad rage of bi-amping applications.
The parametric equalizer section features independent level, "Q" and frequency controls that let you contour your sound in virtually any way you like. And the filters - essentially a built-in electronics crossover network - have independent frequency and level controls for both high-pass and low-pass bands.
Natural, independent HPF and LPF outputs are provided from the crossover section. There are both unbalanced 1/4" phon plug and balanced XLR outputs for connection to any power amplifier or sound reinforcement system.
Send and return jacks are also provided for insertion of external signal-processing equipment, and a built-in headphone amplifier with an independent level control which permits private monitoring.
Find out how broad a sonic spectrum your bass guitar can really cover with the Yamaha PB1