I owned a used one for a year or so in the mid 90's. Ultimately it developed a problem no technician could readily fix. So I traded it on a D125. The D70 was very warm sounding, musical and involving, but with less detail and air than more recent ARC amps; also a full upper bass, and much less deep bass. I liked it, but while I regretted being forced to sell it, the D125, or for that matter the more recent VT100 series, do sound better; in contrast the VT60 and CA50 gained detail but lost warmth; in the past month I've auditioned the VS55 and VS110, albeit neither properly run-in, and these seem to continue the predictable shift towards detail and control over overt warmth. If you do buy a D70 I'd clean all the circuit boards before use too, and probably put in new tubes, not from Audio Research as they're very expensive, but from thetubestore.com or another secondary retailer. You'll also need an equivalent pre-amp - mine was and remains an ARC SP9MkIII, which has been utterly reliable and sounds great - I also auditioned a MkII version which was good enough, and some solid state (cheaper) alternatives that were hopeless. If possible, I'd try to audition a combo at home, for a week, and make sure it's reliable - some of my problems only surfaced when the amp had been switched on for an hour or so; others on start up. The sound might strike you as being wrapped up in big warm hug - just be careful it doesn't steal your wallet after the initial embrace. Cheers, Rob.
