Primaluna dialogue premium HP tube rolling suggestions to reduce brightness

The stock Primaluna Preamp tubes in the 2 middle slots were way too bright for me. So if you want to go with new production tubes. I would suggest the reissue Mullard 12au7's. If you want to experiment with old American tubes. You might want to seek some Baldwin or Conn organ pulls for less than $30 a pair. Triode mode will help as suggested.

George HiFi-  since you seem to have a better understanding to the technical concepts, perhaps you can explain this to me. The amp has output terminals for 4, 8 and 16 ohms.  While my proacs are 8 ohm, when I run them using the 4 ohm terminals, they sound better - bigger soundstage, more air around the instruments.  If it matters in the equation, my set up requires me to run about 4 meters of speaker cable (I cant place the amp next to the speakers)- which I am using Kimber 8TC bi-wired.

Everyone Else - I have reached out to Kevin at Upscale about the V11&12 tubes and will see what he recommends. I will check out aniwolfe's source, too.  When you say the re-issue Mullards- are these the Russian made tubes? 

@meiatflask

Yes the Mullard reissues are Russian. Jared is usually my go to guy at Upscale when it comes to tube recommendations. Kevin can be difficult to get an good answer from. Just my personally experience.

Also I want to add. You shouldn't be forced to use only Triode mode with your amp. If so, then what's the point of owning it? I prefer to use UL most of the time.

If you are sure about which impedance terminals sound the best you can try some very inexpensive new stock JJ tubes in the 12AU7 spots.  
The JJs come stock on the Cronus Magnum and are a dark sounding tube but still capable of great sound.  This will be an inexpensive way to see if you are headed in the right direction.  You can get JJs 10 bucks each.  

aniwolfe- I prefer the ultralinear mode, too, primarily because the soundstage is much bigger, which is why mini-monitors and EL34s have been at the heart of my systems for decades.  What else is in your system, if I may ask?