I use my M-125's in triode mode with two (rather than four) output tubes running.
I could go with another pair of M-125s, of course, or look at the VTA-120 or VTA-70 for biamping the tweeters.
Are the gain structures of these choices identical?
Can either be run in triode mode, like my M-125s?
Can the VTA-120 run KT-120s?
I know some of the answers are in the specs, but wanted to get them all in one place.