Quality tube, great performance
Installed a pair of the KT88’s in a McIntosh MC60. Please with the performance. Clean crisp sound, no distortion, no hiss or noise. The tubes have very little “blue glow” from traces of gas left in the tube which ionizes under high voltage; this is one indication of good manufacturing techniques. Some other brands of KT88 tubes (and 6550’s) have had considerably more blue glow when used in the MC60.