McIntosh MAC 3 (my last dumb qustion, I promise)

[ChicagoDog]

So, instead of a MX 121 for basic 5.1 surround sound needs in my 2 channel rig, is a MAC 3 the better choice?? Remember, I want nothing else but #1 pure 2 channel pass through and #2 the ability to use simple 5.1 for an occasional movie and tv. I'd save $2k which would go a long way towards fancy cables (LOL) But seriously, if I run stereo RCA cables out from my MDA 1000 (and hopefully later from my C1000 or C500) into the analog input of the MAC 3 is that then acting a pure pass through when the input/mode select knob on the front of the MAC 3 is set to analog? Is it then just "pure direct" 2 channel with NO extra A to D and then D to A conversion with that hook up and setting? I can run my hdmi from the direct tv box, amazon fire tv box and dvd player into my television and optical into the back of the tv into the MAC 3, turn the knob on the front to surround, turn on the other 3 amps and I'm in basic, no frills, low cost 5.1 business right? An at the same time, no compromises to my 2 channel system, the MAC 3 would just act as a pass through, pure ad simple in analog mode with volume control?