I've tried Philips tubes, JJ, Sovtek and RCA. Now I have to say that the differences TO MY EARS (disclaimer: personal experience, no universal truth) are fairly small. I was lucky enough to stumble upon a Philips E288CC SQ. That is indeed the best sounding tube I have, but the difference with the standard E88CC from Philips is subtle. So don't start spending fortunes on very rare tubes - first try out the cheaper ones so you get a feeling of what you can achieve with tube rolling.
Best 6DJ8 tubes?
I have a Carver C-19 pre and SDA/490t cd, both use 6DJ8 tubes. Both units were recently serviced and had Sovtek tubes installed. The tubes in the cd player only have about 10 hrs on them, but the sound isn't nearly as warm as it was before replacing the stock tubes. I was wondering if anyone could recommend the best brand I could use, if 6922's would improve the sound, and the standard burn in time for the new tubes.