ECC801S Siemens & Halske, copper posts, NOS specs V72/ 73

Description

Pair Siemens & Halske ECC801S made in Munich by Siemens & Halske in 1967 & 1968

This is a pair ECC801S tubes produced by Siemens & Halske in Munich. On tubes date codes: CØ6 # 7C & CØ6 # 8E are visible; they indicate 1967 and 1968 as production dates. Very healthy tubes with good specs; see test results.These ECC801S tubes have a copper grid and halo posts and a half box plate with one square hole. This is the longlife, tight tolerance version of the ECC81/12AT7. This tube was made exclusively for governmental institutions and manufacturers of high precision gear. One of the tubes is an army selection.

Sonic

This tube type is highly regarded; I refer to the few threads on the web for more information. Excellent valve for the preamp section; low noise, very smooth extended highs, tight bass. Balanced and smooth sounding, recommended!

Test results

Both tubes test NOS. The internal balance between the triode sections is excellent. The tubes are matched. The measurement data below illustrate that the tubes are in good condition. 

Valve   V72

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

11,6 / 11,9 mA 6,0 /6,0 mA/V OK

=  NOS / NOS =  NOS / NOS

Valve   V73

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

11,5 /11,7 mA 5,8 /5,8 mA/V OK

=  NOS / NOS =  NOS / NOS

Where NOS is : Ia = 7,0 to 14,0mA, Gm= 4,5 to 6,5 mA/V.

For test methods and factory specification read the tube testing page.

Short description