Thoughts on Audio Research D70

Daveyf
I had one from about 1984-1988. It had very good sound. Very tube like, yet precise, smooth, plenty of headroom, etc. The problem I had was that it runs its 6550s _very_ hot. I had two or three rather spectacular failures during the time I owned it. Each failure resulted in sparks, smoke, charred circuit boards etc. I would get it back two weeks and $200 ('80s money) later working and sounding perfectly, but I held my breath every time I turned it on! IN my book, it gets an A for sonics and a C- for reliability.

Peter

I had a D70 MK11 for about five years in the mid-80s. Excellent sounding amplifier with very few sonic flaws. My unit was totally reliable. The unit was very critical of the 12AX7 used on the input. If the tube was not quiet (LN or SLN) the sonics suffered as well as the life of the tube. After I changed to RAM SLN tubes all my problems went away. The D70 in the mark II version this is still one of the better sounding amplifiers available.

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.

I have had a D70 MK2 with an Sp9 MK1 since 1988 with no problems.I bought the SP9 new when it came out ($1700 in 1988)and the D70 ($1000 1990 floor model )from a dealer with used tubes. I ordered ARC tubes and used them for a long time. The ARC tubes are better. Back then it was about $200 for a set. I have had the set for 20 years with Vandersteen 2Cs. Tired of the audio bug and just listened to music.