The album cover of the Chronologie album tells us in writing what instruments Jean-Michel Jarre used on the album. Quote : "Instruments: Digisequencer, Kurzweil K2000, Mini Moog, ARP 2600, Akai MPC-60, Akai S 1000, AKS, JD 800, Korg 01, TR 909, DR 660, Synthex, Eminent, JP 8, DJ 70, Vocalist, Fairlight." Link with album cover images : lpcover.wordpress.com/tag/jean-michel-jarre
My first hardware drum machine was actually the successor to the 660: the DR-770. I got on well with the little blue and orange 770, but found that my ears would get tight/fatigued if I spent too much time banging away at it; the 770 had perhaps more brightness and top-end sizzle than I (or anyone) needed at the time.
I sold my 770 and picked up a used 660 based on the following:
Reviews from owners of both machines stating that (despite way more sample memory on the 770) they found the (smaller) selection of sounds on the 660 more usable, despite it's flatter, more lo-fi sound quality. Keep in mind, this was around 2000 or 2001, when "CD quality sound" was still a big selling point, and digital instruments that fell slightly short of that technical benchmark (like the 660, which I've heard is 12-bit) were seen as second-rate by some.
The 660 had two individual outs for routing snares/hats/etc to their own FX/mixer channel. The 770 had just one extra out. For my FX-heavy musical fumbling of that era, 2 individual outs meant "twice as good!".
Separate, dedicated buttons for (MPC-style) rolls and flams, instead of one switchable button for both on the 770. I was listening to a lot of IDM/drill'n'bass at the time... rolling AND flamming in the same recording take somehow seemed important to me.
Roger Linn had reportedly worked on and/or designed the 660, but not the 770, and Tom Jenkinson was on-record as having sequenced all drums on all albums (to that point) using a 660... so, despite the 770 having pretty much the same sequencer, I wasn't above biting into some of the 660s very specific mojo. Roger Linn has since downplayed the depth of his involvement with the 660, but he was still (AFAIK) on a contract with Roland and provided some design input... good enough for me. Maybe they just wanted him on the payroll to avoid any bad blood, given how similar the 660 was to the MPC's layout & approach?
The 660 was dressed in black: all business... and therefor sexier. The 770's plastic colors, while still reasonably tasteful for this "Groovebox" era of gear, didn't really fit it's design, intent, and sound... the colors said "I'm fun! Bang my pads! Make Crystal Method beats", but the actual experience was "serious drum sequencer for serious(ish) musicians". In both intent and execution, the 660 and 770 are more of a budget, ROMpler-only version of the MPC-60/3000 than any kind of sibling to contemporaneous products like the MC-303/505. I still have a DR-202 somewhere, it couldn't be more different... mostly for the worse.
Anyway... I overestimated how much use I'd get from the extra outs and extra roll button, but the sounds didn't disappoint: they were indeed more fun, flat, and useful for lo-fi electronic beats, with the standout being a great range of aggressively-late-80s "dance" snares. Most every sound on the 660 starts off somewhere between 80s Phil Collins and Fine Young Cannibals, but you can quickly edit them into something you'd wanna hear for 3 or more minutes. A decade later, when I finally got a real TR-808, I remember being disappointed that it's snare didn't have the same cutting presence as the single 808 snare sample on my 660... I tweaked in vein to trying to get the real deal to match it's much more cost-reduced great grandson.
Note: I've heard the 660's sample set was sourced from the library of the earlier Roland R8 drum machine and it's expansion cards -- a late-80s instrument now considered a classic by some folks, and still getting action on recent Aphex Twin releases. While I haven't verified this sample-origin story myself, it's worth nothing that, even if true, the converter (output) quality on the 660 (being a budget unit aimed at the lower end of the market) is likely to be a bit of a step down in spec from whatever ended up in the much more expensive R8... whether or not that ultimately makes the 660 sound better or worse than the R8 is up to you and your ears. I've yet to demo an R8 in the flesh.
A couple years after all that, Legowelt helped me discover the crusty joys of Chicago's Dance Mania label, and the dozens of (forgive me) "Ghetto" House tracks and proto-Footwork tracks that used nothing more than the DR-660, a mic, and some attitude to make underground party vinyl.
I eventually learned to love my TR-808's snare on it's own terms, and I really don't hammer on the 660 much anymore... but I'd never sell it. Despite sounding a little grainy and muffled by today's 24-bit DAC standards, the 660 represents (for me) a damn good idea, executed perfectly... and the over-achieving it's done in the world at-large since it's release is testament to how right Roland's planners, designers, and Engineers got things with this very approachable 1992 gem.