QUESTION about Installing "Matched" Tubes

Hey folks,

I have Conrad Johnson Premier 12 monoblock tube amps, 140W/side. And I’m replacing the old 6550 output tubes.It’s 4 6550 tubes per monoblock.


I usually just replace the tubes with whatever CJ recommends a the time. But this time I splurged for Svetlana Winged C NOS tubes. I bought two pairs of matched quads.


My question is: How do I go about placing them in the amps? Is it required, or best, to put each matched quad in each amp? Or does it matter which monoblock all the tubes go in?


I’m asking because at the moment I’m not sure which tubes are actually matched. They were measured before shipping, with the Plate Current and Transconductance number’s written on each tube. But frankly, not being an electronics guy, I don’t really know what they mean and how it helps me match the tubes, if they do.


So for instance, there are numbers on each tube:



46.8/4740
42.2/4410

41.4/4870
38.8/3970

42.8/4830
39.5/4470
41.3/4810

41.9/4770

Do I, for instance, try to find the 4 tubes in which the Plate Current numbers are closest in value? Or the Transconductance number?


NOTE: My CJ amp allows for user biasing of each 6550 output tube!


Thanks for any info!