Made in Germany
Telefunken Diamond Bottom
Telefunken EF89 / 6DA6 Equivalent
Round Grey Plate
Top Ring Getter
New in White Box
Amplitrex AT1000 Tested
Up for sale is a strong matched quad (4 Pcs) of rare vintage NOS Telefunken EF89/6DA6 RF/IF pentode vacuum tubes, packed in white boxes. Precision-manufactured in Germany, these authentic Telefunken valves feature the iconic diamond bottom logo in the glass base, round grey plates, and a top ring getter. Renowned worldwide for their immaculate German build precision, ultra-low noise floor, outstanding gain linearity, and exceptional longevity in classic receiver circuits and audio applications.
All four tubes have been tested on an Amplitrex AT1000 automated valve tester at nominal factory specs. Anode current (Ia) and Transconductance (mA/V) measurements alongside percentage performance ratings relative to standard specs are detailed in the table below.
| Serial No. |
Tube Triode |
Plate Current (Ia) |
Transconductance (mA/V) |
| Ref Spec |
Result |
% Ia |
Ref Spec |
Result |
% mA/V |
| SR.NO. 5314010 |
T1 |
9.0 mA |
7.4 mA |
82% |
3.50 mA/V |
3.10 mA/V |
89% |
| SR.NO. 5314009 |
T1 |
9.0 mA |
7.8 mA |
87% |
3.50 mA/V |
3.40 mA/V |
97% |
| SR.NO. 5314014 |
T1 |
9.0 mA |
7.5 mA |
83% |
3.50 mA/V |
3.40 mA/V |
97% |
| SR.NO. 5314013 |
T1 |
9.0 mA |
7.6 mA |
84% |
3.50 mA/V |
3.20 mA/V |
91% |