It might be within the product info packet, or on the back of the speakers. I did a search, but the manufacturer is not exactly completely forthcoming with regard to specs. They quote a 6 Ohm nominal impedance but there is no mention of a minimum impedance, and the frequency response is without +/- dB's. They also quote a sensitivity of 91 dB 1 watt/ 1 meter, and the suggested power range is between 40-175 Watts, but don't mention if that is per channel or total per pair.
Based upon the available specs, it would seem that either ss or tubes might work.
http://www.monitoraudio.co.uk/support/past-products/silver-rs/rs8/#/specification
Based upon the available specs, it would seem that either ss or tubes might work.
http://www.monitoraudio.co.uk/support/past-products/silver-rs/rs8/#/specification