Thoughts on Audio Research D70

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.

Anyone want to part with their D70? No tubes OK (even better). Itching to do a total rebuild project with it.

I work on them and retube them. Use ARC tubes only. Excellent amp. After 2000 hrs it's time for an output retube. I also set the bias down to 62-63mV @ 120Vac. Doesn't hurt the sound and runs a bit cooler. Very good amp. The D-115 is basically the same circuit with 2 more 6550's per channel.

As Hifigeek notes, the circuit is almost identical to the D-115 but with 4 output tubes instead of 8. This is a really nice tube amp, along with the D-115 and for the price of purchase on the used market, if in the market for a tube amp, you can't do better at the price, at least I haven't heard it. With improved caps and careful selection of input/driver tubes these amps can really compete if lacking the ultimate detail, air and bass control of much more expensive tube amplifiers. The build quality is superb as ARC is noted for. You can't lose, the prices used on these amps are higher now than 15 years ago indicating their continued value.