PS Audio 5.0 Preamp Manuals

I recently acquired a PS Audio 5.0 preamp. It sounds good, really good in fact. However there are some settings that I don’t understand on the preamp and I do not have any documention about the 5.0 other a page from an advertising brochure that must have been from the late 80’s. Is it possible to obtain copies of the Users Manual and/or Service Manual for the 5.0 Preamp?