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
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