Goldlion KT77 vs KT90's

I'm thinking on it. Let us know if you come across a good deal on a couple of quads.

The KT77 was the MO Valve version of the 6CA7, or the EL34.
The KT90 is a tube that was developed by the Ei tube company in Yugoslavia in the late 1990s to be a more Powerful Octal based Beam Pentode.
The B+ for the 6CA7/EL34/KT77 is considerably lower than for the KT90, and while the KT90 has the same Pin-out, the operating conditions are different.
Hope that this helps,
Happy Listening

Jimborjrib ,- all in the for what it is worth context - I have a Cronus Magnum with the KT90s. I haven't tried the KT77s in this amp or EL34s for that matter,had another amp that accepted EL34s and although I prefer a somewhat warmer sound the EL34 wasn't to my liking. While you didn't ask this, for comparison purposes the old Lion KT88s I use in my Ayon Spirit 2 are a warmer tube than the KT90.

What 12ax7 and 12au7s are you using? My Cronus came with Sylvanias, after awhile I switched in RFT 12au7s and Tungsol 5751s which to me gave a warmer touch.