Audio Research D70 mark1 + schematic

Stewen 1, I don't think there are multiple versions of the Mk2. My D70 was updated at the factory to Mk2 status, which the factory still has record of.
You might check with ARC, as previously suggested, to get more info on your amp....just give them the serial #.

I wasn't inferring Audio Research service isn't good, just that I doubt they would "give" you a schematic. They may be more than willing to sell you one, if they have it. I assumed Stewen1 was looking for a quick and easy freebie, so that's why I made the comment. Since the dawn of (Audio Research) time the only way to contact them was on the phone or snail mail, no e-mail, let alone downloads. I hadn't been to the Audio Research website in a while, I normally go direct to ARCDB since there is more information there, but I took a look just now and was surprised to see they now offer downloads of manuals. Welcome to the 00's Audio Research! (I'm being facetious). For Stewen1, the bad news is the D-70 is not included.

What are you trying to fix? Maybe you won't need schematics.

Thanks for Your answers ! Well , I might manage to fix this amp without a schematic .... the MK 2 schematic is a good help
even if it differs some from this amp , many values are the same. I have soldered a 3K resistor in parallell with each
trimpot to slow it down and make it less sensitive. Now , with
new NOS Siemens E88CC its very easy to set those +90VDC .
Tomorrow I´ll put in the new 6550 Tungsol reissue powertubes
and set the current to 60 mA or so . I have some problem to
order new 800-1000uF/450V caps from Mouser . And that 530uF/150 V cap too . Another question : is it silly to
spray a trimpot with oxidecleaner ? Or/and contact protect ?

Stewen 1, do post again once you have had a chance to listen to the amp. I will be VERY interested to hear your thoughts.
IMO, this amp is one of the very best low power amps that ARC made and is still HIGHLY competitive with the latest offerings.