Although I'm not very experienced with tube equipment, I am aware that an OTL type amp may be the only tube-type design that can drive a load of that nature. The OTL designs use no output transformer, but instead have a cathode follower output tube so that they can drive lower-impedance loads with better stability & coupling. Joule Electra builds such a design; no doubt there are others as well.
Also refer to this thread "tube amp for a difficult load":
http://audiogo5.iserver.net/cgi-bin/fr.pl?aamps&1000150251&read&h24&zzlWellfed&&
Also refer to this thread "tube amp for a difficult load":
http://audiogo5.iserver.net/cgi-bin/fr.pl?aamps&1000150251&read&h24&zzlWellfed&&