Short out? Who told you that, it's wrong. MLs do dip to around 1 0hm at very high frequencies, but that is far from a short. Also, there is very little energy in that frequency range, so there's no reason to be concerned about the amplifier. The Yammy is at no risk at apartment volumes if you leave enough air around it.
I believe your Rotel amps are fine and that you are getting ready to move up to a better pre-amp or pre-pro than the Yammy is. In my experience, at apartment volumes the pre- part is much more important than the amplifier.
Ha det bra,
Ralf