Germany tube codes >>> -
http://www.tubemaze.info/deciphering-european-tube-date-codes/-
http://www.tubecollection.de/ura/codes.htm VALVO was an old and renowned german company. their tubes are of
excellent quality, and at least as good as for example Telefunken,
Philips, Mullard or Siemens tubes (of course - i'm referring to
the originals, only).
according to my experience VALVOs are often even better than Teles !
in fact, Telefunken had gotten tubes from VALVO since the early 30s,
put the diamond-logo on and sold them as "Telefunkens". at those
times nobody really cared inspecting a tube very closely to possibly
discover its real origin (knowledge of where to look for what wasn't
widely spread, either).
since you're asking,- here's a bit of history: before 1914 the company
"C.H.F. Mueller GmbH Hamburg" produced only X-ray tubes (therefore, they
were known as "Roentgen-Mueller"). after 1916, probably triggered by the
requirements of WW-I, "ordinary" tubes (mainly Xmitting ones) were added
to the program.
in april 1924 Mueller created a daughter-firm called "Radio-Roehren-
Fabrik GmbH" or just "RRF GmbH" (meaning radio-tube factory); they took
over the tube-production from Mueller.
in 1926 RRF was renamed to "VALVO". that name was inspired by the latin
word "valvae" (something like door wing, to symbolize the flow-control
of electrons), plus the english "valve". since then VALVO used their
typical logo, a sort of jagged ring with a stylized "VALVO" written
inside, which was kept (almost) unchanged for more than 5 decades.
in 1927 Philips bought C.H.F. Mueller (Mueller had financial problems),
and later in 1932 also VALVO (Mullard became a Philips-daughter, too).
BTW, Philips was founded in 1891 as "Philips & Co" for producing and
selling light-bulbs. after significant expansion also internationally
they changed to "Philips AG" in 1912. AFAIK their headquarter has been
in Eindhoven (holland) ever since, till today.
VALVO didn't just produce tubes (incl. camera/pencil/Geiger/PM types, &
up to 1 MW klystrons), but a whole lot of other stuff like ceramic caps,
piezo-elements, ferrites, smaller motors, transformers, deflection-yokes
and (b/w + color) picture-tubes, diodes, transistors, loudspeakers, etc.
it's amusing to see how eagerly people are sometimes pointing out major
differences (prices follow accordingly) between tubes e.g. made by
VALVO, Mullard, Telefunken, Siemens or Philips. one should be aware of
the fact that tubes were frequently exchanged & re-labelled among those
and other firms.
as an aside,- Telefunken started off with the prototype of their very
1st EL 34 (metal-base) in october 1954, which was an exact copy of the
VALVO EL 34 (Philips had developed the EL 34 years before). at that
time, only some slight changes were done by the Telefunken engineers
(e.g. the lower pair of cooling-wings was dropped); later other mods
followed.
tubes (not the very early ones) made by Philips, VALVO or Mullard (with
their mother Philips) all have the Philips/VALVO/Mullard date-codes, and
for me there's not really a difference. the same is true for those tubes
made by Philips (i use Philips as a generic for Philips/VALVO & Mullard)
which were sold under brand-names like Telefunken, Siemens, Hoges, RSD,
Ultron, Triotron, Haltron, Mazda, Adzam...
"distributors" like Ultron sold not only quality stuff made by Philips,
Telefunken etc., they also put eastern-europe tubes (maybe chinese, too)
into their boxes. therefore, tubes labeled with the logos of some less
popular brand-names are not at all just junk,- but one has to carefully
nit-pick the goodies.
the bottom line is, that i can honestly encourage you to look out for
tubes made by VALVO (but only the originals), regardless what logo they
have - if you can find them.
"Kevin Deal / Upscale Audio" <
ke...@upscaleaudio.com> wrote:
> Valvo tubes were sometimes made in a Philips owned factory in
Germany...but
> most were made in Holland. They bear a resemblance to any other
Mullard,
> Amperex, etc.
for what i know, VALVO tubes were manufactured exclusively by VALVO GmbH
in Hamburg,- labeling is a wole different story. the factory or company
which supplied a tube sold under the names Philips/VALVO/Mullard can be
read off from the PVM date-code: e.g. "D" stands for VALVO/Hamburg, "B"
for Mullard Blackburn Works Ltd. (and later Simonstone Works Ltd.), ">"
for Visseaux/france, "-" for Amperex/NY, an inverted "T" for Telefunken
etc.; there're many more factory-code symbols.
> If you bought them recently folks should be aware that there is a guy
> selling Teslas that are re-labeled as Valvo on an "audio shopping"
website.
> Fake tubes, fake boxes.
interesting ! i bet these tubes don't show the typical characteristics
of a genuine PVM-tube (e.g. the date-code etched into the glas)...
however, not all people are aware of this and might get tricked.
