4 x Genalex Gold Lion KT77s...already fully burned in. I am not sure if the silicone rings do something or not, but they fit snugly...and the quad sounds absolutely great. As I said in my previous post, I have more than a few “New Sensor” Russian tubes of various types (not KT88s !) so I am used to their sound, and the GL KT77s are the best sounding of them all...including the mighty TS KT150s. I mean, as triodes in Euforia. Clean, clear, dynamic, spacious, with deep
, tight bass, and (most important) with a lot of the midrange “magic” of the classic EL34s. The GL 77s are true beam tetrodes, and (critics say) the most accurate reproduction to date of the original, legendary Genalex KT77, an scarce and super expensive tube, even more so than the original KT88s.
They enjoy glowing reviews, but (as allways) it all depends on the amp being used. They certainly sound great in Ultralinear amps like my PA, (also in SE amps) and I must add that they are even better as triodes in the OTL Euforia.
As powers In my PA, bass was super strong & deep ( a bit too much for my tastes) but in Euforia their “triode bass” was way more controlled, precise, musical, while being some of the
deepest bass ever from this amp. I do not value that much the “strongest” bass, like the thunderous one from the KT150s, (probably without peer in this regard) but the most precisely defined. In fact, the 77s deep bass taxed my Senns HD579s to their limit...clearly a job for higher cans. Anyway, the KT77s quad proved fantastic as preamp tubes, with soul, life, “punch” and not a trace of the usual “dryness” of most new production tubes...