here at Eurotubes took a step back when we first auditioned the new JJ 6550!
Most 6550's and especially new production versions are pretty sterile sounding compared to the classic European KT88 equivalent. So
our benchmark was to A/B the JJ 6550 against some of our NOS GE, RCA, Sylvania
and Coke bottle Amperex 6550's. Most of the time JJ Electronic tubes will hold
their own with NOS equivalents or even surpass them but in the case of the JJ
6550 our expectations were totally surpassed. They are very warm
with a great clean tone and the breakup is raw, crunchy, and gritty. If you want an
Angus - AC/DC type tone then these tubes really deliver! they are simply a lot
of fun to play. The JJ 6550 will not make as much power as the JJ KT88 and the
KT88 is thicker sounding. In fact some players feel it's too thick, so if you
want a fatter sounding tube than a 6L6 that breaks up earlier than a KT88, the JJ 6550 may be just right.
Unlike some of the original GE 6550's and the New Censor variations, the JJ 6550 does not internally connect anything to the metal base ring. These are safe to use in all applicable applications.
After a 24 hour burn in all power tubes are tested for noise and matched at multiple operating points for plate current (± one milliamp) and transconductance.