12AU7 tubes for a Rouge Audio Sphinx V3 Integrated

Mullards never worked for me- just did not care for the overall sound.

FYI the JJs take a LONG time to burn in- they ship with McIntosh too and don't really smooth out until 700 hrs or so- no joke.  

In the mean time try amperex bugle boy, made by amperex philips or RCA 5963.  clear tops are too bright IMHO.  

@rar1 Interestingly enough, I read somewhere (either a magazine review or Rogue literature) that tube rolling was not necessary. 

Interesting point if this is true, and might be telling about this particular amplifier and it's design - - and how the tubes are incorporated in the circuit in this amp.

If changing the tubes in this amps makes little difference, some might say "why have tubes in the circuit at all". Changing 12au7 input tubes in all of my amps and colleagues amps, we hear a notable difference with different tubes vintage or new.

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.