Cary Audio CAD-280SA V12R

I put  Mcap Supreme Silver/Gold (non oil) I had both. I thought it was Supreme Alu.. I had to leave the room for about 45 min.  Making some pretty wonkie noises. settled in a bit, after 6 hours of playing, sound almost SS like. Razor sharp. KT88s. I've never seen an amp that was so easy to work on, cap swap, interior cleaning, tube pin tighten, put back together, wax it, retube and bias in under 2 hours. 

The sonic change is not subtle at all.. It went from tubie to tight. I bet the el34s sound great. If they could just keep the highs like kt88 or 90s and the mids like the el34s and the low mids like kt88 or 6550. Maybe a KT66/6L6 haven't tried it yet...

We'll see 

The stock Ruby EL34 (Shuguang EL34-BSTR) sounded the smoothest with the Mundorf SESG Evo (non-oil) Supreme caps in my V12R amp, and I was using vintage RCA EL84s and Siemens 12BZ7s or RCA 6922s on the front end (50w Triode) mode.

With that said, my Cary SLP-98 preamp did have Jensen Oiler caps in it with vintage 6SN7s. On that amp I did use all OFC copper neutral interconnects and OFC copper bi-wire speaker cables. No silver. The combo was really nice, smooth, holographic.

With what I'm doing and listening too, the Stock Ruby sound a lot better than before, 12bz7 and EH EL84 with the old Audio 1 didn't work.
With a12ax7 or 12az7, Mullard el84, El34s or KT88 yes. NOW ..after the cap change it's really gone up a notch on SQ, they were very sonicly gifted before, now. Even easier to revoice and no signal tubes, the 12at or az work with all the power valves...Using 6l6s right now, not sure on that one, need 8 more valves, to get a good feel. 6V6s are on the way, surplus sovex, NOS...
I have some RCA BP, but I hate to use top notch, if so so will do. This machine really has the ability to use ok tubes and make them sound really good...Great engineering. Wonder what the mono blocks are like?
These are plenty powerful. BUT I'm use to 300+ with the VTLs.  Never used it but they drove everything I use very well..

I did a PC swap a few days back... 3 copper/silver mill speck teflon poly vinyl cover #10s and 1 # 10 ms copper, did a weave. Worked very well
sounds just as good, as MITs that are broke in just off the bench... Light NOT FLEXIBLE.. I like it...

Really good coupling caps  do influence the outcome. After I did mine on my former V12R and now current Mono Tube amps, I could THEN truly hear the differences with input/output tube changes -and- interconnect changes too.

I had the R and you want the R version in my opinion.  Also, decooney is correct. Good luck!