Tubes for Conrad Johnson Premier 11a ????

I know this isn't to point but I thought I'd offer this experience: I changed the small tubes to NOS RCA's with what I considered to be quite dramatic effect. I won't try to detail the change but there was significant across the board improvement.

My experience in speaking with CJ about using KT88's instead of 6550's was similar to Art's. I never tried the KT88's because CJ said that I would not be able to bias them in my amp.

The Premier 11s and 12s are wonderful CJ classics - both were designed and originally voiced for the GE6550A. Those have become a bit scarce lately, but if you run across a quad, they're well worth paying a bit more. The SED (nee Svetlana) 6550C is an Ok replacement. The original Tung-Sol 6550 is a bit of a wholly grail tube difficult to locate and v. expensive.

Rolling the small driver tubes can change the sound of the amp more so than the power tubes. The RCA clear-top 6FQ7/6CG7 is very nice and the ~1958 Sylvania 6FQ7 is even better. The RCA black plate 5751 2 mica makes the stock CJ National seem rather lifeless.

Check with Andy at Vintage Tube Services.
 
Tim