6-voice rackmounted module synthesizer, introduced by Akai in 1986.
This is virtually an AX73, but stripped of the keyboard. The control panel and widely appreciated LCD are largely unaltered from that of the AX73. Left and right line out jacks and a headphone jack, all 6.33 mm ø are located on the front panel; MIDI in, out, and thru as well as the 13-pin DIN sampler jack are all confined to the back of the unit.
The exterior of the VX90 was originally black, but for the final release changed to the light-gray surface that is Akai's trademark. It retains the same army-tank feel established by AX73.
Not a cut-and-paste writeup. Various Internet resources were used. Your Uncle Dudley owns an AX73.