Wayne Parham Messages: 18787 Registered: January 2001
Illuminati (33rd Degree)
I don't know about the KT120 or the KKT150, but I do know about the KT88 in an Audio Note Kit 2. It doesn't last nearly as long as a 6550. This is true of all brands, but JJ has been worst for me, sometimes lasting as little as just a few months.