Description
Siemens & Halske 12AT7WA / ECC801S German army selection, made in Munich by Siemens & Halske in 1973
This is a 12AT7WA (ECC801S) tube produced by Siemens & Halske in Munich. On the tube a date code: CØ5 # 0B is clearly visible; it indicates Februari 1970 as production date. Very healthy tube with good specs; see test results.This tube is assumed unused; no visible traces of use. The tube a double support halo post and triple micas in order to reduce microphone to an absolute minimum. Half box plate tube. 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.
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
V71 |
Ia (plate current):
Transconductance (Gm): Gas test, Shorts test: |
10,3 / 10,5 mA
5,3 /5,4 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
| Tube type | ECC81 |
| Quantity of Tubes | One tube |
| Brand | Siemens & Halske |
| Manufactured in | Siemens & Halske, Munich, Germany |
| Dates | 1970 (CØ5 ± 0B) |
| Construction | 2-hole ribbed half box plate |
| Getter Construction | Triple micas, double getter support |
| Print Condition | See pictures |
| Box included | Generic whites box |
| Equivalent tubes: | ECC81, ECC801S, 12AT7 |
| General test results | NOS specs |
