There's not a lot of information out there about the JV-80, it's basically known as the precursor to the hugely popular Super JV/XP series of Roland ROMplers/workstations (and then XV, which turned into Fantom) and that's about it. I've had the rack version (JV-880) and one of the keyboard variations (JV-90) for a while now so I thought I'd share some information about these synths and what they're good for. They are fairly capable synthesizers that are often overlooked as just simple ROMplers.
Roland's first digital synth, the D-50, was released in 1987. It was a very good sounding synth that was capable of covering digital and analog type sounds. They designed a couple other synths with this technology (the MT-32, and D-5, 10, 20, 110) while at the same time they introduced some semi-pro ROMplers (the U series). These ROMplers were just that, very simple single voice ROM playback instruments with no filter. Their next step was developing what was to be their top of the line U series, the U-50. This synth was basically a U series x4 voices plus filters, so now approaching the synthesizing depth of the D-50. Hearing that the D-50 was still selling quite well, they decided at the last minute to call it the D-70. Unfortunately it was plagued by unnecessarily complicated interface and poor documentation.
The D-70 not being that successful, they took the technology and experimented with a couple of different directions.