What makes Telefunken tubes sound better?

BTW: Don't give me any static about the stereotyped tubes, in
that video! =8^)

The Germans have been absolutely anal, with regards to
materials, quality and engineering excellence, for a great
many decades. The notion that someone else's products(new or
old) could exceed their standards is laughable. I've tried a
number of other tubes, and would not consider any nine pin
miniatures, other than either(50's or early 60's) Siemens or
Teles. Right now; my CDP has six Siemens(grey shield) CCa's
in it. The proof is in the listening! Then again; there are
many out there that appreciate the colorations(ie:
warmth/tubiness) of other brands. To each their own.

I might mention, as I have elsewhere; the EAT tubes are the
closest anyone has come, in recent years, to the quality of
the earlier products. But then the OP mentioned cost!
(http://www.musicdirect.com/c-673-vacuum-tubes.aspx)

Actually; some of the best tubes were manufactured for, "Post Germany" in the 1950's -60's. ie: The CCa is a special low noise, low microphonic, long-life E88CC/6922. Philips had similar designations for the Dutch Post, some tubes that were selected had PTT and BP lettering or etched designations, but they were the same as a top specification E88CC. The, "German and Dutch Post" consisted of telephone, telegraph, and telex, tube technologies, which required a very low noise E88CC/6922. A CCa is the same as a 6922 but was tested and certified with high mA, RP, and Mu and lowest-noise audio threshold. Most of the telephone centrals used vacuum tube technology equipment for telephone equipment, requiring a "noise-free" environment. The ECC803S(1950's) was selected for long life(10K hrs), S/N ratio and ultra-low microphonics, for use in avionics/aircraft radios. The letters, "CC" probably equate to, "double triode." For a special low-noise design, in the 6922 family; the frame-grid inner construction, was actually invented by Amperex USA, and appeared everywhere in the 6922/E88CC designs of the day, including Siemens Halske, Telefunken, Amperex, Philips, and many other brands.

@Mr J- The author of that article would have made Julian
Hirsch very proud. I'm certain, if he had reviewed tube
equipment; he wouldn't have heard much difference either. The
sonic differences between various iterations and year of
manufacture, within the same
family of tube, and the various brands, are usually anything
BUT subtle or, "tiny." Nor, in my experience, are
the differences dependent on the equipment(usually).

@Geoffkait- It's interesting how broadly a topic can get
off course. Back to your conversation: My comments were
restricted to small signal, nine pin miniatures. All my
favorite octals originate from the 40's and are military
designated, especially the Sylvania 6SN7W(JAN-CHS,
metalbase/tall) and Tung-Sol 6SN7GT(JAN-CTL, round plate).
I'm currently using those as phase splitters and
drivers(respectively), in my monoblock amps. I cherish
them, as the best of the best octals, followed by the
Syvania VT-231 & Ken-Rad 6SN7GT(JAN-CRC), both bottom
gettered. BTW: I love chopped liver, especially on a good
crusty rye.

Generally speaking; the monetary value that people place on
items, is a pretty fair indicator of how good they
might be(You can fool some of the people, all of the time and
all of the people, some of the time, but- you can't fool all
of the people, all of the time). Yes- there are different
tastes in sonics(ie: clean/liquid/defined and
warm/microphonic/tubey), and a wide variety of brands that
many consider desirable. However; if one checks the prices
that people have consistently(for decades) been willing to pay
for certain offerings, it becomes clear which are largely
considered, "the best," worldwide.

"Unfortunately there are also a lot a fakes in the
market." To date; no one has counterfeited the diamond,
molded into the bottom glass of the authentic(nine pin
miniature) Teles. Easy to spot a phony, or tubes that may
have been rebranded. In the case of Tele's octals(ie: EL34);
it takes a knowledge of their distinct cathode/mechanical
structure to avoid getting burned. A bit of hilarious
Telefunken history: (https://www.youtube.com/watch?v=Lqvvu9ZZfmY)