EL34 Pair, Telefunken German army selection, NOS V271/272

Description

Matched pair of EL34 tubes made by Telefunken in Ulm, Germany

Description

Here is a pair black base Telefunken EL34 valves. The Telefunken EL34 valve is legendary. Produced in the period 1967-1972 in Germany. Most Telefunken El34 tubes were actually RFT tubes produced in the former East Germany. These have good quality but the real Telefunkens are superior. I refer to the many reviews on the web. And they seem to last forever.

This pair bears the German eagle with BWB (Bundesamt für Wehrtechnik und Beschaffung) icon; this means that the tubes were selected for use in the German army. The bright white print is an indication the the tubes have never been used.

Note: my tubes are often not the cheapest. But it is very hard to find better tubes !

Sonics

The Telefunken EL34 is considered by many as an outstanding sounding EL34 tube; a lot better than todays production! I refer, here also, to the many reviews on internet. 

Test results:

The measurement data below show that the quad tests NOS and is matched very well; the match is better than 2%! 

Valve  V271

Ia (plate current): Transconductance (Gm): Gas test, Shorts test:

101  mA 11,7  mA/V OK

= NOS = NOS

Valve  V272

Ia (plate current): Transconductance (Gm): Gas test, Shorts test:

102  mA 11,7  mA/V OK

=  NOS = NOS

Telefunken measuring values for new unused tubes:

• The rated emission value for a new EL34 is:  100 mA. 
• The rated transconductance value for a new EL34 is:  11 mA/V . 

For Telefunken specs info see last picture 

Test condition & equipment:

Mutual transconductance, plate current, gas and shorts test equipment: AVO Mk IV (Dutch army tester) , AVO Valve Data Manual 23rd edition 1981, RFT stabilised mains, Utracer3+, Philips PE 4832, 2x Korad KA3005P programmable power supply, 2x Keithley 2700 and 2x Fluke 145. 

Test conditions: Ua (plate voltage) = 250 Volts, Us (screen voltage) = 265 Volts, Ug = -13,5 Volts and Uf = 6,3 V ± 3% (factory conditions). Please read our test page.

Summarized description