Description
Pair Siemens & Halske E81CC / ECC801S made in Munich by Siemens & Halske in 1973
This is a pair E81CC (ECC801S) tubes produced by Siemens & Halske in Munich. On tube a date code: CØ6 # 3G is clearly visible; it indicates July 1973 as production date. The other tube is identical but there is no visible etch code. Very healthy tubes with good specs; see test results.These E81CC tubes have a copper grid and halo posts and triple micas in order to reduce microphone to an absolute minimum. Half box plate tubes. 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 1
V69 |
Ia (plate current):
Transconductance (Gm): Gas test, Shorts test: |
10,6 / 11,1 mA
6,1 /6,1 mA/V OK |
= NOS / NOS
= NOS / NOS
|
| Valve 1
V70 |
Ia (plate current):
Transconductance (Gm): Gas test, Shorts test: |
10,0 /10,7 mA
5,7 /5,7 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 pair |
| Brand | Siemens & Halske |
| Manufactured in | Siemens & Halske, Munich, Germany |
| Dates | 1973 (CØ6 ± 3G & —— ) |
| Construction | 3-hole ribbed half box plate |
| Getter Construction | Copper grid and halo posts |
| Print Condition | See pictures |
| Box included | Generic whites box |
| Equivalent tubes: | ECC81, ECC801S, 12AT7 |
| General test results | NOS specs |
