Feels like there are two different questions here…
1/ Potentially moving your Roon server to another machine (for convenience)
In terms of sound quality it will make zero difference, unless you’re currently suffering from dropouts or other networking issues from running your Roon (on your MacBook).
But a NUC (ROCK) or Nucleus One allows you to use Roon without opening up your MacBook.
So purely from a usability / convenience point of view having a dedicated always on (zero maintenance) Roon server device hidden away in the closet next to my router would feel like a very sensible option to me.
2/ How to best to connect your Marantz with Roon (for SQ and convenience)
Before you get too concerned that your ‘missing out’ on some better sound quality due to ‘bigger numbers’ be aware that Roon streams to Airplay devices at 16 bit / 44.1Khz.
Which in theory is all you can hear up to anyway (this is a fairly concise and clear explanation of why).
Airplay also works nicely with Roon, allows you to control the Marantz’s device volume in Roon and doesn’t require any additional boxes or software setup.
In fact I’d say one of the more signifiant reasons to move to Roon’s (Roon Ready) RAAT protocol over Airplay is if you have multiple endpoints and want them all to play in perfect sync. If you only have the one playback device, I’d pause and really consider if you need to do anything. Instead maybe sit back and enjoy some music for now…
Of course we’re on an audiophile site, so even if were just chasing numbers people will naturally want to go there…!!
- Peter’s HEOS extension is probably the cleanest in terms of (potentially) not needing any additional hardware while allowing Roon to still control the main volume on your Marantz. Unfortunately you can’t run Roon extensions on ROCK or Nucleus One (two solution to this listed above, but neither time/cost free). It also requires a level of technical setup. Lastly, as it’s effectually a Roon->DLNA ‘bridge’ you may see a very small delay when initial starting playback.
- If that all sounds like too much tinkering then you could just get a WiiM Pro which is Roon Ready (so capable of 24-bit/192kHz) and connect it to the digital S/PDIF port on your Marantz. The one downside to this approach is Roon will control the volume of the WiiM but not your Marantz. You can either set the WiiM to output at a fixed level and only control the volume on your Marantz or you can keep the volume on your Marantz at a halfway point and control the WiiM volume via Roon — mostly people do the latter I expect.