EL34 tubes- alternates to matched octet for Primaluna HP dialogue premium


I have the Primaluna Dialogue Premium HP power amp that uses 8 EL34 tubes.  I am currently using the stock EL34s, but have noticed a nice improvement in imaging when I switched to NOS mullards 12au7s.

As I look at playing around with different power tubes, (especially NOS Varieties) I see numerous sets of matched quads out there, but never matched octets, unless they are new production.

my question is this:  what do I lose sonically by using unmatched tubes, or two sets of matched quads, or four sets of matched pairs?  Wondering if since the Primaluna is self biasing, if it is less sensitive to non-matched tubes than other amps? 


meiatflask
@meiatflask, I have a set of 8 Premium Grade Black Bottle Treasure tubes with about 600 hours on them so they are broken in, pulled them from my VTL MB125s that are boxed up to go back to factory for rebuild, if you pay the shipping to you and back to me, you are welcome to try them out for a month or so. Let me know.
@tooblue - sounds like an offer I can’t refuse.  How do we do this? Can you send me a message/email outside of the discussion so we can word out the details directly?
I experienced reliability issues with Psvanne  Ax7’s.  Wish it were not so, they sounded nice.
@lloydc , FWIW I currently run 10 of Psvane 12A tubes in 6 different pieces with 1,000s of hours with no issues, looking for a piece of wood to knock on, and have had them in the past as well as running the treasure power tubes in my amps, give them a second chance especially if you liked them and make sure they are premium grade.

 
NOS preamp tubes are often affordable and I like 'em, but with power tubes I prefer the new stuff. I've used new Gold Lion KT88s and various Tung Sols including KT120s and 150s,  and they all work well, sound great,  and came with warranties.