I would expect most amps to
survive an 'onslaught' like that, 6 ohms isnt a dramatic increase in load compared to 8 ohms.
It is probably worth noting that whatever quoted impedance is given, it is only an estimation. For certain notes, my speakers present a load of about 3.5ohms - thats from a rating of 8ohms! Usually that sort of thing only applies to low notes and transients but you can see that
all amps have to deal with lower than rated impedances from time to time. 6 ohms for the actual amplifier shouldnt do anything dramatic.
Weaker power supplies may well struggle though, and I cant see the power stage in the Marantz being up to much, because its not actually that powerful (looking at the Class A figures, it is 25W/ch!). Hitting the limits of the internals just comes about faster with 6 ohm speakers, you are asking more from the amp at every amplification level.
For a demonstration of a speaker, this has clear ramifications - you dont know what is under more scrutiny, the power handling of your amp or the speakers themselves! You cant expect 11/10ths from your amp and also expect to judge the speakers - an amp operating outside of its optimum range isnt ever going to do anything justice.
If you are going to move to something like a Monitor RS6, you probably want to look at some better amplification.
For the same money, I have seen Dynaudio Audience 62s go s/h - a 4ohm loudspeaker that is truly magnificent (IMO, of course).
Let us know how you get on with the speakers anyway
OT:
To the poster above:
I have often wondered what gives Rotel amps the sound they have, I wonder if it is all down to putting in a pathetic power supply? To cook a channel from a load like that (unless you were showing it no respect at all) means something in there is seriously under-rated to my mind!
