another point.....
as was said, even the era or vintage of the tube, and not merely its brand name makes a diff!
another take on Telefunken tubes is IMO they render the top ends as sweet and clear as one could ever hope for, but do little to keep the lower end as adept. I felt Telefunken was not the choice if more dynamics and transparency and improving the Botton end was the desire... so there's another reason why one definitely needs to dip some toes into these waters and find out for themselves.
one last note. Amperex on par in the 60s era at least produced as transparent and strong a bottom end tube as one could hope for, and this was across several models.... 6922; 7308; and 12AT7; 12AX7.
each of these tubes although aimed at differing applications produced similar sonics. all of these tubes I've used in various preamps. some amps use the 6DJ8/6922;7308, to split the incoming signal as they are all dual triodes. often this occurs in hybrid amps. PSA for example uses this approach in their current upper end amps.
its important as well to indicate the application to the tube seller. phono preamps for eX. are best suited to have as quiet a tube as possible. not every tube seller can address this area as well as some other tube sellers but its always something one should say. the better tube vendors will keep phono preamp tubes separated from standard line stage and charge a bit more accordingly.
that said, I'll opt for the phono stage preamp quieter tubes every time. even in std pre amps. why not? pay a tad more for less noise
