Apparently ARC don't sell manuals and in anycase it would mean ringing them as there is no contact email address and that isn't easy due to the time difference.
There is a contact email address:
Contact us
Audio Research Corporation
3900 Annapolis Lane North
Plymouth, Minnesota USA 55447-5447
For service requests, please contact:
service@audioresearch.com
Phone: 7 6 3 - 5 7 7 - 9 7 0 0
F a x : 7 6 3 - 5 7 7 - 0 3 2 3