I have an SET Class A Tube AMP and a Marantz SS amp connected to a Douk Audio "LITTLE BEAR". It can also drive two sets of speakers too so you have up to 4 amp/speaker combination. Key is the Little Bear presents a LOAD to the tube amp even if not selected. Some tube amps require that to be powered on. Been using it for two years with zero issues. Now, Amir at Audio Science Research poo poo’s this unit due to noise but I am thrilled with it.
The Luxman speaker selector switch mentioned above appears to drive 3 pairs of speakers on one amp ? Not familiar with it and I can't any manuals to confirm it can handle 2 pairs of amps....