Hi again,
David, if you are considering the 4-ohm M80s/EP500, I'd suggest you move away from the Marantz and consider Denon and other brands which, historically, have had no trouble driving 4-ohm loads.
While according to one source of mine, Marantz and Denon (and Sherwood Newcastle) all come out of the same factory, they do not have the same engineers designing them.
The brands of AV receivers that Axiom as found have no difficulty driving the 4-ohm M80s are Denon, Sherwood Newcastle, NAD, Rotel, Outlaw Audio, and B&K. I think there is a series from Yamaha RZ? that are also OK with 4-ohm loads. Others here may recall which Yamahas are OK with the M80s.
Regards,
