Thanks, Al, for the precise answer and the very relevant link.
OK to Use Both Balanced and RCA Inputs?
On a power amp, tube or solid state, which has both Balanced and RCA inputs, is it OK to connect, say, a turntable (via a preamp) to the Balanced input and (at the same time) a CD player to the RCA inputs? Naturally I would play only one at a time, but does having cable plugs in both inputs present any problem for the amp? I am thinking in particular of the Audio Research VS115. Thanks.