Be sure the levels are matched and double blind trial if you can. Audiophiles are notorious for falling victim to placebo effect. You’ll prefer the louder of 2 sources. If you expect something to sound better, it will. In the case of playback to a USB DAC, there should be less transport effects like those I’m about to describe.
When I notice a difference, it is usually in air and space. Voicing is unchanged but I’m 69 and have some codger’s high frequency attenuation.
This is most apparent for me when delivering bits to an Apple TV 3 vs a ChromeCast audio, both TOSlink connected to a Parasound P5’s internal DAC. It is subtle. To give a couple of examples, Joey Alexander’s Countdown record and Chris Thile and Brad Mehldau jazz/newgrass mashup. Both were ALAC transfers I made using iTunes converters.
Today, I have a HiFiBerry Digi+ schlepping bits and it sounds much like the Chromecast Audio. I’d be hard pressed to tell the difference. Again, both are TOSlink and SPDIF interconnects.
With the non-apple endpoints, piano play sparkles and the notes dance in space. With the ATV, the openness and sparkle was diminished.
This was pretty repeatable across all of my good material but is most obvious on small ensemble jazz. Amazingly, Snarky Puppy’s Sylva record has that same feel. This record is Metropole Orkest plus Snarky Puppy playing big band funk/jazz. It is a close miked, multi-miked monster. Each instrument had at least 1 mic and some two. The mix down is amazing. Engineer was wizard in placing everything in space. And it is damned good modern orchestral music.
The ATV was fed 44.1 RedBook data. The ChromeCast/Roon transport was up-sampled to 192/24. The upsampling transformation appears to help significantly. So we can attribute changes to the different playback signal processing chains in use.
I first noticed this behavior with Plex and it persisted across the migration to Roon. There may have been some gain difference in the two paths as a result of different design decisions with regard to headroom and overflow prevention or loss of significance prevention in the floating point. When you hear a difference, it is likely a result of implementation decisions made to ensure that the output is really well behaved.
I’m going to play both of these disks in the Cambridge 851. It also upsamples to 192/24 before conversion. It can provide balanced and unbalanced audio and TOSlink. Both would be affected by the upsampling in the CD player. The P5 also upsamples to 192/24 using Burr Brown parts and Burr Brown converters. John Curl did the analog bits. My recollection is that the 851 sounds very much like Plex/Roon to Chromecast or HiFiBerry.
Associated equipment: GAS Ampzilla (original) and Dhalquist DQ-10 mirrored. Seriously spacious. I find that the presentation differs significantly with playback level. For the magic to happen, piano level needs to be similar to live unamplified play. Dialing back for casual listening looses the magic.
Roon Core runs on a Debian instance in a BHYVE VM under FreeNAS 11. Three switches are in the digital path, 2 Netgear unmanaged rack switches (8 port) and a Ubiquity 8 port POE switch in the distribution cabinet. The way in/out is through a Netgear Orbi and Netgear cabel modem.
I’ll play these records with Roon on the Mac. I’ve only used Mac Roon for local listening with the internal iMac speakers. These are OK but the sound is definitely muggle. No magic this way.