12AU7 tubes for a Rouge Audio Sphinx V3 Integrated

Hey @mesch you can have fun messing with different 12au7s in that unit. Also seeing the lower version standard white MCaps used in yours stock. You can do better here too. I’d call Rogue first and ask them what upgrades (tubes and cap changes) they’ve tried or taken notes on from customers. Maybe they will share more. Not always. Most of the larger mfgs use basic JJs for low cost, availability, and reliability in new-production amps produced in volume.

If it helps, my current mono tube amps use both 12au7 and 12at7s for input and drivers. Tried at least 20 different au7 pairs (mostly vintage), and while some of the best are my vintage "close triode matched" mid-60s Mullards, yes, was able to find a nice smooth tone with newer production Psvane au7s as an alternative.. If you want new production vs hunting matched triode pairs of vintage tubes, you could try the psvane 12AU7-S Art Series / ECC82. Viva and a few others sells them. They are fairly smooth and open up a little more after they are run in 75+hrs. Using psvane now in my current mono tube amps. Not too bad.

@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.

@mesch the article @juanmanuelfangioii shared from enjoythemusic makes an interesting comment. I also own some of the absolute best-of-best Blackburn plant Mullard 12au7 cure-tracer close matched triodes from Brent Jesse too, similar to what @dekay may have been referring to above.

Sure, they are nice, expensive. and my other PSVANE 12au7 hold their own against them comparably, and I can run them all of the time with no worries. My amps came stock with JJs, and there are select au7s that sound much better, imo.

Noting this comment in the recent Pharaoh_II article link above, quote:

• "My comparisons of the Pharaoh integrated amps were based on using only stock tubes for evaluation. I did substitute in a couple of rare vintage NOS Mullard 12AU7 tubes in the Pharaoh I. It got me closer to Pharaoh II, but not all the way. The tubes cost $300! The people at Rogue Audio have great ears and they choose tubes to go in the production models very carefully"

When you call Rogue, maybe they can share more about why some of the more recent designs including the Pharaoh_II (reportedly) may sound better. See what they say, and why?

@mesch if you can, try to take listening notes first 20hrs, 100hrs, 200hrs. Often times people don’t give it enough time with the stock tubes -or- internal caps before replacing them prematurely. Me included on a few occasions. Good lessons learned.

While I’m over here making cool upgrades on mine, friends chose to "leave it alone" keeping the stock tubes and caps in their units for 200-300hrs. Their new vs. well burned in amps and stock tubes, caps, sounded better, given some patience and extra time.

Then say at 200hrs if/when you still decide to swap in other vintage tubes, you’ll know what changes the changed tubes actually make. For your consideration.