You mentioned the Doge 7 tube dac. I have one with 6 nos 12ax7
West German Telefunkens and 2 GEC Marconi 12au7 power tubes
I stream hi-res with ifi Neo streamer to a Vincent Class A hybrid
amp to Forte IVs. The Fortes were a bit too sharp until I put
the Vincent in the mix replacing a Yamaha as2200. I also had
tried a SET amp but both the class A/B Yamaha and the Decware
SET emphasized certain frequencies that made the tweeter
horn too aggressive. The class A (for first 10 watts)
Vincent brought serious weight to the bottom end of the
Fortes and made everything gel and balanced them out nicely.
I spent alot on tubes though and recently bought a tube tester
where I found the majority of the cheap Chinese tubes
that came with dac tested bad and all but one of the NOS
tubes I purchased tested good after several years of use.
The Chinese tubes were only in a couple months so go figure.
Bottom line is I now have an amazing bottom end to match
the amazing midrange and highs. The Yamaha is a great
amp but I couldn’t quite get the same weight in the bottom
even with tone controls and the SET is more of a tube rolling
toy considering its just 2.3 watts per channel but very good
too in its own right. I’m curious aboout R2R dacs too but my streaming
already sounds as good as my vinyl with the Doge so
I can recommend it if you want to deal with tubes which
can be fussy. I'll bet McIntosh SS with R2R is amazing.