I’ve been playing both these tubes this week. I have primalunas, both tubes are from gold lion, new production. In my system the differences are very easy to hear. The 66s have more top end emphasis, and perhaps a bit more transparent, though that could just be the added detail on top. The 77s are warmer, more midrange emphasis. The bass is about the same on both. I could see some people saying the 77s were more natural sounding and the 66s more “HiFi”. Overall I prefer the 66s. I was told by someone at Upscale that the primalunas mate better with the 66s based on the amps’ transformers, but I don’t know any more about that. Having owned the stock El34s, other El34s, and the 77s, I can say that the 66s were definitely a change in sound overall and I was glad I bought them. What do the KT88s sound like? I need to try those!
KT-77 vs. KT-66
As I've had my QS Mono 60s, I've tried a variety of tubes. I have sold off my KT 150s, and use KT-88s from time to time, but what I really love are KT77's.
I'm thinking of getting some KT66s, thinking that lower powered tubes are better (to my ears) matches for my system. I just don't know what the KT-66's sound like.
Question: If you have compared KT77 and KT66 tubes, what would you say the sonic, audible characters of each are? Is there a difference you can hear? What does the KT66 sound like -- to you?