I just got an Email from CE Distribution announcing the following three new output tubes from JJ ..
"CE Distribution, the primary distributor of JJ Electronic vacuum tubes, is pleased to announce the release of three new JJ tube types. JJ Electronic has been producing premium vacuum tubes in the Slovak Republic for over 16 years. JJ products are known in the industry as the best-sounding and most reliable tubes produced today.
The three new tubes are all very welcome additions to the JJ line: the 6550, 6CA7 and EL844. The JJ 6550 is musical in every sense of the word and will improve the sound of your high-powered bass and guitar amps with punch and clarity. The 6CA7 is a large bottle version fo the classic EL34 that gives a bigger and warmer sound than any EL34 in the market today. It is a substitute for all amps that use EL34s. The last addition to the line has been designed by JJ from scratch, an EL844. A substitute for any EL84, the EL844 has lower gain and a more balanced, dynamic sound."
The 6550 tubes should work just fine in a Dynaco Mark III, VTA ST-120 or the new VTA M-125 monoblocks. A 6CA7 is pretty much the same as an EL34 and should work well in any Dynaco ST-70 or Mark IV. The new EL844 would be the tube to use in your Dynaco ST-35 or SCA-35. If anyone does get a quad of either of these three tubes in the future maybe you could comment here on their sound. JJ does usually produce good sounding tubes but their quality control is sometimes not the best. I guess time will tell ..