Differences in tubes.

I was also wondering how the KT-77 compares with the KT-66 tube? I'm also a fan of the EL-34 tube. Beautiful sounding mid range. I've been considering the Gold Lion tube. Running with Quicksilver amps...Thanks...

KT-66 is a 6L6 variant from an electrical standpoint and should only be used in amps that can accept the 6L6 types. Interstingly, the "KT" in these tubes originally stood for "kinkless tetrode" so they differ from the pentodes and beam power type tubes. If you like the EL-34s try the 6CA7 tube which is a direct sub, but is actually a beam power tube having the beam focusing element. They sound different and they sound better in some circuits than others. The GE 6CA7 is quite nice, but there are modern EH and Chinese versions as well. These are the "big bottle" EL34 variants.

If you're still using Triangle loudspeakers, you may want to call Kevin Deal at Upscale Audio in SoCal (see the A'Gon Guild). He's a Triangle dealer and (I think) a Jolida dealer who specializes in tubes/tube amps and may have some useful thoughts for you.

Marty