I collect the old SUNN amps and I have used them sence 1965. I currently have 2 1000s heads, 1 1200S, 4 Solarus heads,
2 Model T's, 1 studio PA head, 1 Spectrum head, 1 A212 combo and two early top control heads, one of which is the Mark III Dynaco that I pruchased with the original GEC KT88's. I used to use nothing but NOS RCA's and Tungsols because the KT88's were to expensive. Three years ago I got into the JJ Electronic tubes and found that their KT88 sounds killer in my SUNN stuff. They sound a lot fuller and smoother than any 6550. I do run the bias at about 50 to 60mA which is pretty warm but that's where they sound the best. I have tried the Svet's and the sovtek KT88's but I much prefer the JJ's, the tone is sweeter.