Setup:
 
iPhone 6 -> Tidal -> Lightning-to-USB Adapter -> iFi USB cable -> iFi Micro iDSD DAC section -> amp under test -> MrSpeakers Alpha Dogs
 
The Lyr is a Mk I bought new from Schiit two weeks ago for $329.  It’s running NOS Pope PCC88 tubes (rebadged Amperex Bugle Boys), about $120 from Upscale Audio, so total cost is $449.  (Too lazy to put the stock tubes in for another comparison, sorry.)  The iFi was bought new for $499 from Music Direct two weeks ago.  Cans are MrSpeakers Alpha Dogs, bought 2 weeks ago.
 
I’ve been using everything extensively, and believe it’s all run-in (can’t say I noticed much/any change), but could be wrong.
 
Result:
 
Spoiler alert: Lyr wins.  [With Pope PCC88 tubes.]  It’s better in every way.  It’s warmer; with bigger bas and richer mids; bigger, wider soundstage; more refined; more natural; holds a groove better; more fun.  Maybe more resolution?
 
iDSD is good; but thinner; brighter (more treble extension?); grainier & brasher; smaller sound.  X-Bass and 3D effects mostly improve, but still worse than the Lyr.
 
Cheers,
Dunc
 
P.S. – Got some NOS Amperex 6922 PQs on the way, so will compare to the Popes when they arrive.  And maybe also the stock tubes…

What settings on the iFi Micro iDSD did you use during the test? Which Filter, Power Mode, etc.?
Thanks!