Genuine Telefunken (Made in Germany)
ECC81 / 12AT7 Dual Triode
Grey Plates
Top Ring Getter
Diamond Base Bottom Marking
New in White Box
Amplitrex AT1000 Tested
Up for sale is a strong pair (2 pieces) of authentic vintage Telefunken ECC81 (12AT7) dual triode vacuum tubes, pristine and packed in protective white boxes. Manufactured in Germany, these legendary tubes feature smooth grey plates, a top ring getter, iconic glass print, and the famous molded diamond logo in the bottom glass base. Highly revered by audiophiles for their exceptional detail, neutral soundstage, low noise floor, and ultra-long operating life.
As shown, both tubes have been precisely tested on an advanced Amplitrex AT1000 tube testing system operating in full fixed-bias mode. Plate current (Ip) and mutual conductance (Gm) measurements alongside percentage performance ratings relative to nominal factory specs are detailed in the table below.
| Serial No. |
Triode Section |
Plate Current (Ip) |
Transconductance (Gm) |
| Ref Spec |
Result |
% Ip |
Ref Spec |
Result |
% Gm |
| SR.NO. 231056 |
Triode 1 (T1) |
10.0 mA |
8.2 mA |
82% |
5500 µMhos |
5060 µMhos |
92% |
| Triode 2 (T2) |
10.0 mA |
7.4 mA |
74% |
5500 µMhos |
4860 µMhos |
88% |
| SR.NO. 231004 |
Triode 1 (T1) |
10.0 mA |
7.8 mA |
78% |
5500 µMhos |
5020 µMhos |
91% |
| Triode 2 (T2) |
10.0 mA |
7.6 mA |
76% |
5500 µMhos |
4880 µMhos |
89% |