12AU7 tubes for a Rouge Audio Sphinx V3 Integrated

I believe the best-sounding new-production 12AU7s are the Psvane ART series (Viva Tubes).

If you go NOS, then the world's your oyster.  So far, Amperex are the best, IME.

Brent Jessee has 1960's Amperex/Heerlen and Mullard/Blackburn short plate 12au7's starting @ $150-$160/matched pair (damaged printing/relabels).

These are what I ended up with in the preamp that I have been using for 20 years now.

I prefer a harmonically rich, liquid 3D sound.

For around $100/MP he also has RCA 1950's RCA black plates.

I used GE 5814's that I also liked, but I can't get to them now to see what type of construction/plates they have  (they were smooth but lacked the mid-bass bloom of the others mentioned above).

RCA clear top/side getter are not warm sounding tubes (you would want the 50's version with black plates and top flashing if you go that route).

I've never purchased tubes from him (Brent Jessee), but he has a good rep (plus he has the goods and testing equipment).

I purchased my various tube stock 20 years ago.

I have not tried any of the new production 12au7's.

.

DeKay

Amperex 7316. Smooth as a gravy sandwich.

+10. RCA clear top….

I actually used in Pharaoh…which to me brought out the best in the unit.

My rogue set up is ST100 power amp with RP1 pre, so not sure if this is helpful. I've experimented with a handful of tubes in the 12au7 and 12ax7  spots and best combo for me without a doubt was Mazda 12au7 and Telefunken smooth plate 12ax7. I was actually surprised how much of a difference the 12ax7's made in the power amp. Brent Jesse tubes is a great resource btw, he responds to emails quickly, tubes descriptions on his website are very helpful, and he has a wide selection. Good luck!