Options to improve digital sound

Get a Roon Nucleus Plus revision A on Ebay or USAM around $600.00. Upgrade the power supply (s-booster).  $400 or so.  Plug in external hard drive or install internal.  

Use DSP to "tailor" sound.  Use high quality cables, they do make a difference.  You are familiar with Roon.  A very painless way to go.

@audphile1 Roon Core is where vast majority of processing goes on, the relatively complex interface of Roon is processor intensive. CPU's working at relatively high rates creates more noise and higher latency, both are enemies of resolution  Higher latency also means greater chance for timing issues. The reason so many find Roon inferior to the proprietary music players is those music players have been designed as to require far less processing and deliver lower latency, result is both increased resolution and more analog like sound quality. 

As for empirical evidence, I've had a variety of Endpoint and Core streamers, the Cores have a far greater impact on sound quality vs the Endpoints. I'd suggest its both the processor, latency issue, and the fact Core sits upstream of Endpoint. Contrary to certain popular opinion, noise introduced anywhere in the streaming chain cannot be eliminated within the offending component by components  further down the chain, no getting back resolution, latency lost. 

I purchased both the SonicTransporter and Roon Nucleus, but returned the ST7. I found the Nucleus’ software to be more stable. The ST7 had frequent connection issues in just the two weeks I had it. 

Thanks @sns 

I do realize there’s a lot of irrelevant tasks in the mac mini that can potentially impact sound quality by negatively impacting roon related processing. I’ll be trying a dedicated core soon. Can’t wait to see how it impacts the sound hopefully it’ll be a positive difference. 

I'm certainly not the first to say this, and surely won't be the last, but the streamer is right up there with the dac in order of importance in streaming chain. I don't care about all the signal and network filters, audiophile switches, lps, etc., these all just band aids if streamer and dac not optimal, the full potential of these devices will only be realized after attending to dac and streamer. 

I'd also add a totally maxed out mac mini can be a very nice streamer at a certain price point. I learned a lot from incrementally optimizing my mac minis. Optimizing operating systems, quality RAM and linear power supplies are critical for streamers, powerful processor for low latency next. The proof of need for a powerful processor with Roon was crystal clear when I was running both Roon and Audirvana with the minis, Audirvana always had superior sound quality to Roon with all three of my minis. It wasn't until I obtained my present custom build server (I9 Intel processor, Euphony operating system, Optane industrial RAM, powered by $6k JCAT Optimo ATX lps) that Roon sq surpassed Audirvana, adding the second streamer as an Endpoint/renderer added that much more. Roon is capable of sq equal to or better than very nice vinyl setups, seemingly requires more extensive optimizations than streamers with proprietary music player apps. I should add Roon sq superior to the Euphony Stylus proprietary music player app with my setup, very few Euphony Stylus users agree with this.