Would be nice if the OP would have given better info on what he is trying to find ( like the brand name, which was Acoustic Research ).
maybe this will help......
http://www.classicspeakerpages.net/IP.Board/index.php?/topic/1884-ar-p-10-power-amp/
maybe this will help......
http://www.classicspeakerpages.net/IP.Board/index.php?/topic/1884-ar-p-10-power-amp/