Made in USA
RCA 5814A / Premium 12AU7
Red Print
Black Plates
Top Ring Getter
Triple Mica Construction
New in Original Box
Amplitrex AT1000 Tested
Up for sale is a matched pair (2 Pcs) of highly sought-after vintage NOS RCA 5814A premium dual triode vacuum tubes, packaged in their original RCA Radiotron factory boxes. The 5814A is RCA’s heavy-duty industrial/military grade drop-in upgrade for any standard 12AU7 / ECC82 circuit. Featuring classic red print logos, dark black plates, a sturdy triple-mica structure for microphonic damping, and top ring getters, these vintage USA tubes are renowned in Hi-Fi audio for their deep, authoritative bass response, musical midrange, and smooth, non-fatiguing top end.
As shown, both tubes have been thoroughly tested on an advanced Amplitrex AT1000 tube testing system 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. 4468001 |
Triode 1 (T1) |
10.5 mA |
8.5 mA |
81% |
2200 µMhos |
2100 µMhos |
95% |
| Triode 2 (T2) |
10.5 mA |
8.8 mA |
84% |
2200 µMhos |
2100 µMhos |
95% |
| SR.NO. 4468002 |
Triode 1 (T1) |
10.5 mA |
8.6 mA |
82% |
2200 µMhos |
2100 µMhos |
95% |
| Triode 2 (T2) |
10.5 mA |
8.2 mA |
78% |
2200 µMhos |
2100 µMhos |
95% |