Thoughts on Audio Research D70

Johnsonwu, good to see that you like your modded D115.
I feel this way about my D70Mk2 and IMHO it's one of the best sounding
ARC amps. I have a feeling that this is why Dick Olsher bought one too!
A stone cold classic!

@DaveyF: great to hear u are in love with your D70 all these years... much like me --> my Counterpoint NP220 Premium Gold. I am surprised that Olsher didnt mention anything about converting it into triode. I was under the impression that he's all for triode glow.

Johnsonwu, I actually have not owned the D70mk2 for more than about 18 months. However, I am pretty enamored of this amp and would recommend it to anyone thinking of a great mid powered tube amp. BTW, I have a feeling that Dick Olsher is into good sound like the rest of us, and if it comes from triode or pentode isn't the main issue. Just so long as the gear can portray music. That is my way of looking at gear, I'm not attached to triode or pentode or tubes vs. ss or whatever, IF the piece under question sounds great, that's what I'm looking for. Isn't that what we are all seeking?

Johnsonwu ... G'day ... I have just scored a D-115 MK2 for a second system ... I didn't pay very much & haven't seen one since the 80's ... I use Beast OTL's I built for my main system but love the "classic" Tx coupled amps. And I'm looking for an SP-8 to partner it. I use a slightly modded CAT MK3 as my main pre.
I noticed in your thread you were doing some modifications to the 115 .... is there a thread that discusses mods for these amps? I am also just checking it over at the moment & looking for a schematic to figure out what adjustments can be made ... particularly how to adjust bias.
ARC doesn't have an email to request a service manual .... intact I really don't know much about them so I'm not sure they'd sell me one?? any clues?? Would you know where I can score one? quite willing to pay.
Interestingly this piece suffered the same fate as yours ... I got it from West Australia & it travelled to Cape York ... which is a remote area of Far Nth QLD on the East Coast - I'm about 680kms NW of Cairns on the Gulf coast - so the guy I bought it off packed it in quite a good box but used styrene foam as the buffer!! of course its weight was way too much & I have bent rack mount handles, broken fuse holder, fascia damaged but salvageable ... and a few marks and scratches. It took a month to get here via Darwin! anyway, if you can refer me to any sites or net areas that can give me the info to at least bias this unit ... I'd be much appreciated. I paid $500 for it & dates on the O/put Tx's indicate a 1987 build. It also has 8 x GEC KT-88 which test at around 90% ... I'm subbing KT-90's which I prefer. My email is Cinerama55@yahoo.com

cheers .... Ampex53

In the mid 80s, I used to put the D-70 on Quad 63s (with custom stands) for my clients.

Sometimes used Entec subs, sometimes not.

To this day, some of the most lifelike and stunningly involving music reproduction I was ever privileged to hear (within its dynamic envelope, of course).

I suppose the D70 was colored to some extent, but, IMO, it remains one of the most listenable amps ARC ever made.

And I go back with ARC to be early 70s, and worked there from '76-'77.