12x7 tubes

I have a Black Ice Dac and have rolled many tubes.  I prefer a warmer tube so my favorites are Mullard f91/92 long plates late ‘50’s are just exceptional.  Pricey not overrated in my ears but the real deal. Close second are ‘50’s Rca long Black Plates are excellent.  Sylvania Gold Brand 5751 3 mica black plates are another pricey tube and excellent.  5751’s have  plenty of gain and I don’t notice a difference. I had early ‘60’s GE long gray plate (2 staple holes on each side of the gray plates) these don’t get much love but they are almost as good as the RCA black plates very nice durable tubes.. Telefunken’s were too clean and bright for me and feel they are overrated for their price..  They do work well in my phono pre though...good luck on your search.  It’s a fun journey.

Brent Jesse is an absolute prince among men. Every purchase I have made from him has been nothing short of an excellent experience. I can’t recommended him strongly enough!

having had the black ice/jolida dac (in chris johnson upgraded form), i would agree with the op in wanting a warmer smoother tube in its output stage

that said, i would add that that particular unit benefits greatly from bypassing the front panel volume control for improved sound quality... (if it is not needed for the headphone amp function, of course)

 I was in checking tubes out on BJ’s website and saw he had Ge/ Kentucky Radio pewter plates in stock.  You might want to inquire on those.  A little more cost than the Tungsram and Ge long gray plates.  They are exceptional ...as good as RCA black plates.  Probably the best Ge 12ax7.

Just order a pair of Tungsram 12x7 from Brent Jessee website. I will let you know how they sound with my system.