WiiM into Outboard DAC

I've had an Ultra for about a year now.  It replaced my JRiver/NUC system with FLAC files on a NAS.  The Ultra was out of the box, so much easier to use, no Win10 updates to foul things up, no fiddlyness from JRiver, which is a decent program but falls well short of the intuitive WiiM GUI.  I use the internal DAC to drive a vintage system, and optical out to a slightly higher end DAC to drive Magnepans.  Both systems in the same room but different preamp/power amps in play.  I could use the USB out on the Ultra but I found it was even faster if I used a USB connected drive.....didn't want to use the single USB and a switch....that seemed a bit too much.  When I initially a/b tested the DACs, internal vs external, the difference on the vintage system was pretty subtle, while the Maggies benefitted by the better DAC.  YMMV, as always, but I just bought another Ultra to stream from the drive on the first Ultra for a different room.  Internal DAC is fine for that system as well.  I also bought a Pro to add to the network to supply the mediocre ceiling speaker system elsewhere in the house with the same song files as are on the main Ultra.

From a slightly different (entry level) perspective, I went from YouTube Music and Chromecast Audio to Wiim Pro and Amazon Music Ultra HD.

I can hear the difference. It sounds better, yes. But to me it’s not life changing, and not night and day difference.

Everything I googled including multiple AI agents- say that an upgrade from lossy YouTube music to lossless Amazon music would be far more noticeable to me than an update from a Wiim dac to an external dac. Which could be zero difference based on my amp, speakers, room treatment and so on.

Specifically for my speakers (HPM-100) AI said it would be zero difference regardless of dac.

I’ll take their word for it, as personally I was 99 percent happy before switching to lossless, and I’m 99.9 percent happy now 

After reading this forum and watching endless YouTube videos (I don’t watch much regular TV), it seems that the weakest link of the WiiM streamers is they suffer from a relatively lousy clock circuit, meaning perhaps more jitter than you want. 

Using an Ultra’s USB (asynchronous) output to a DAC should (in theory) mean that the assumably better clock in the external DAC should be buffering the data and streaming it out via its output devices with better timing. 

YMMV.  I have a WiiM Ultra but have not yet purchased an external DAC for it, so I can’t speak to that assertion as some of the YouTubers have. I’m looking at a price commensurate one, perhaps the Schiit Mimir at $299 or if I wait, they might update the Schiit BiFrost 2/64 next year since it is one of their remaining DACs that doesn’t yet support Forkbeard.  Will they go with a similar set up to the Mimir (an off the shelf DAC chip feeding their own home rolled DSP filter) or keep the BiFrost a multibit DAC? Curious about that.  

The WiiM DAC in the Ultra is ok. It measures pretty well. It’s definitely listenable. Not sure a $300 Schiit would be any kind of upgrade.