Ok I'm confused. Re read it and still baffled.

I took the SPDIF(RCA) out (digital out) of all three and plugged them into the digital inputs on the MDAC. I could then switch easily between each digital input. I could also use the preamp to compare the balanced analog of the ms600 and the balanced out of the mDAC and switch between them using the preamp.

There was minimal difference between the three as digital sources. I'd happily test the 818 but not likely to get the opportunity. And the analog out of the MDAC fed from any of the three was better than the analog out of the MS600 IMHO.

Meridian MD600, MS200 and MS600, Denon 4308, Audio Research Ref 110, Krell FPB-400cx, Focal Electra 1007Be and 1000Be, Whise 319a