I agree with JohnK. Try it with your Rotel. It will likely be fine, because the combined impedance curve won't remail at 3.4 ohms across the entire frequency range. Impedance curves are rarely a straight line. Impedance rises and falls with frequency.

You can't hurt your Rotel. It will either accept the load or, worst case, shut down temporarily. I doubt the latter would occur.

Regards,

Alan Lofft,
Axiom Resident Expert (Retired)