German Metal Tubes (Stahl-Roehren) 

Copyright (C) Wumpus´s Old Radio World, 2000, Berlin, Germany
Updated 01/17/2008

In Germany metal tubes are in use since 1938. Advantages of the metal tube: No grid cap, low internal capacities, short connections, low heater energy, good shielding. With other glass tubes these tubes formed the "harmonic series". The data of these tubes were matched to each other.

The German types were shorter but thicker in relation to the American metal tubes like 6V6.

AF- final amplifier tubes with the original size of the metal tubes weren't built. Only the DL11 and EDD11 could offer smaller AF power.

There were different forms of the metal tubes in use, which were different in the length of the metal bulb.

Concerning the tube UCL11 (actually a glass tube of the "harmonic series") romour has it that they were also produced as metal tubes.

Tungsram produced metal tubes which had a glass bulb under the metal capsul.

After WW II Telefunken (production site Ulm) built some tubes with substitute glass bulbs: Examples UBF11, UCH11.

RFT (ex. GDR) built "metal" tubes with glass bulbs in larger quantities.
Example: EF12 (above right.

RSD (ex GDR) built "metal tubes" model "UCH11" with a glass type UCH81 under an aluminum cap!

Tungsram (production site Wien) built "metal" tubes with a glass bulb under a metal cap. UBF11.

Hint for RFT "Metal" tubes with glass bulb. Year of construction code (examples): 44-55 = Week 44 in 1955, 2453 = Week 24 in 1953.

Some adapters were built in former GDR to replace metal tubes with modern glass tubes.
Example: UCH11--> UCH81.

Nahaufnahme eines Stahlröhrensockels

List of tube bases.

Metall- und Glaskolbenroehren der "harmonischen Serien"

** was built with glass or metal bulb (wurde mit Glas oder Metallkolben gebaut)