kt88 vs 6550

You shouldn't have any problem. They're interchangeable.

http://en.wikipedia.org/wiki/6550

Giddy up! Replace those fuses (Isoclean or HiFi Tuning) while your changing to the Genalex Gold Lions.

Spin the Yellowjackets.

Check with CJ tomorrow to make sure. They seem married to
the 6550.

When I checked with CJ regarding my CJ power amp, I was told that if I used KT88's instead of the 6550's, biasing the amp would be a problem.

well CJ says they have already selected the best tube based on the design so i have just kept 6550s in my two CJ 150 W mono amps.
now what i REALLY want to know is can my MV75A1s be converted to EL34s and triode like the MV60 and 55 can be!!
i have way too much power going on in that ultralinear 6550 thing happening. i want to hear what triode is all about. maybe Mr. Behr will chime in here he used to be a dealer for CJ i think in the 80s.