Description
Very early Valvo ECC81. First version; August 1952, square getter.
Once in a life time!
Description
This ECC81 is produced by Telefunken in Berlin Germany. The tube is one of the very first ECC81 tubes that Telefunken has produced; August 1952. The glass is bumpy and limited transparent. The tube was not yet equipped with the classic Telefunken diamond in 1952. The etter is a rectangle that is welded at an angle. The getter flash is brown-black. The tube has copper grid posts, see pictures. Very healthy tube with excellent specs!
Note from the web: The early Philips productions of noval tubes were run on the same lines already in use for rimlock valves. These productions are identifiable by the sharp and regular edge of the base, glass frit bonded or glazed to the body. Another peculiar feature of these tubes is that the electrode pack is firmly welded to some of the base pins, no large mica spacers pressed against the internal wall of the envelope.
Sonics
Although several sources praise this ECC81 version, I have no detailed information about it myself. Nevertheless, it is a sound from the early history of the ECC double triode; a mystery.
Test results*
The tube tests NOS. The internal balance between the triode sections is excellent. The measurement data below illustrate that the tube is in good condition.
| Valve
V113 |
Ia (plate current):
Transconductance (Gm): Gas test, Shorts test: |
8.9 / 9,1 mA
4,9 /4,9 mA/V OK |
= NOS / NOS
= NOS / NOS
|
* Where NOS is : Ia = 7,0 to 14,0mA, Gm= 4,5 to 6,5 mA/V. (Telefunken factory specification see test page)
Short description
| Tube type | ECC801S |
| Quantity of Tubes | One tube |
| Brand | Telefunken |
| Manufactured in | Ulm, Germany |
| Date codes | Ur (August1952) |
| Construction | Rounded plate soldered on pins |
| Getter Construction | Tilted Square getter |
| Print Condition | See pictures |
| Box included | Original Telefunken box |
| Equivalent tubes: | 12AT7, ECC801S, 12AT7A, E81CC |
| General test results | NOS |
