his is a very rare high spec keyboard amp:
This keyboard/mixer combo amp was introduced in 1987 and was discontinued in 1992. It has 4 channels. I/O's include standard guitar plug inputs for each channel along with effects send and return, series loop in and out (for PA and external amp use), direct out and headphone out. Each channel has individual volume and effects sends with channel 4 also having additional bass and treble knobs. Other controls include a 4 band master EQ and a master volume.
It was fitted with a Celestion T4088 G15-150 8? 15" speaker and a Fostex FT300H 8? horn driver fitted on a small plastic horn.