Soundlumia's Opinion
Built and tested according to military specs of the US Navy, Amperex USN-CEP is the most reliable 6922/E88CC tube known to the world: its quality is more than premium, although it doesn't carry the aweing PQ label like its more expensive siblings do; its performance is superb and in fact very few tubes in this price range can claim to be stronger; its low noise should only by judged by the most experienced sound experts because we are talking about the very tube built for and certified by US Navy for mission-critical communication devices; its sound signature is phenomenal (we don't use this word very often to describe tube sound) and many audiophiles consider the "Holy Grail" (1975's Reflektor 6N23P) its only possible upgrade path.
The clarity and sound detail on USN 6922's are second to none. They deliver the same resolution and grip you get from the best German E88CC's but feel less "clinical", for the lack of a better word to describe what Telefunken E88CC's "ultimate clarity" means. These tubes have a clean, incisive presentation, but are also euphonic and musical. Like the Holy Grail's they put all the differing and competing attributes together in one excellent package. As a result, there's no one area they are weak in. The sound stage is not only wide but also deep so every listening experience feels like at a live concert. The instrument separation is not done as beautifully anywhere else, as one would expect from tubes this quiet.
| Amperex USN 6922 E88CC D-getter Pinched Waist Matched Pair - USA '59 – NOS ****SOLD*** |
|
Matched Pair (NOS)
|
Transconductance (mA/V) |
Plate Current (mA) |
| Triode 1 |
Triode 2 |
Triode 1 |
Triode 2 |
| Tube 1 |
13 |
12.98 |
18.576 |
18.569 |
| 104% |
104% |
124% |
124% |
| Tube 2 |
12.76 |
13.44 |
17.564 |
19.544 |
| 102% |
108% |
117% |
130% |
|
Certification Device |
Certification Date |
| RoeTest V11 |
7/29/2024 |
| Amperex USN 6922 E88CC D-getter Pinched Waist - USA '59 – NOS |
|
Single Tube (NOS)
|
Transconductance (mA/V) |
Plate Current (mA) |
| Triode 1 |
Triode 2 |
Triode 1 |
Triode 2 |
| Tube 1 |
11.98 |
12.56 |
15.562 |
15.99 |
| 96% |
100% |
104% |
107% |
|
Certification Device |
Certification Date |
| RoeTest V11 |
9/22/2024 |
Professional Sound Evaluation
The pair worked wonderfully and sounded terrific in our professional studio setup for monitoring.
- Input: Cambridge Audio CXC V2 dedicated CD transport + Schiit Audio Bifrost 2 Multibit DAC
- Amplification: Liquid Platinum Tube Amplifier by Alex Cavalli
- Output: Focal Clear MG Pro open-back headphones
Our full tube sound review was written 100% based on the actual listening experience while this pair of tubes were running in the system described above.
Matched Pair (NOS)
Amperex USN 6922 E88CC D-getter Pinched Waist Matched Pair - USA '59 – NOS
$1,181.75
Professional Tube Testing
This set was tested and certified by RoeTest V11 Professional Tube Testing System with the following result:
Tube 1:
Measured transconductance(GM): 13/12.98 mA/V - 104%/104% (100% = 12.50 mA/V)
Measured plate current(IA): 18.576/18.569 mA - 124%/124% (100% = 15 mA)
Tube 2:
Measured transconductance(GM): 12.76/13.44 mA/V - 102%/108% (100% = 12.50 mA/V)
Measured plate current(IA): 17.564/19.544 mA - 117%/130% (100% = 15 mA)
NO shorts, leakage or gas. NO noise or microphonics.
Curve trace is also included in the original RoeTest report.
Appearance & cosmetic condition
Beside the world-class sound characteristics, we treasure this pair because the pristine condition the two tubes are in - nearly 100% of the paint is intact, and the identical Amperex New York date codes etched on glass are perfectly visible:
7L4 *9E (7L4 = change code, * = Amperex New York factory, 9 = 1959, E = May)
7L4 *9F (7L4 = change code, * = Amperex New York factory, 9 = 1959, F = June)
Single Tube (NOS)
Amperex USN 6922 E88CC D-getter Pinched Waist - USA '59 – NOS
$563.50
Professional Tube Testing
This set was tested and certified by RoeTest V11 Professional Tube Testing System with the following result:
Tube 1:
Measured transconductance(GM): 11.98/12.56 mA/V - 96%/100% (100% = 12.5 mA/V)
Measured plate current(IA): 15.562/15.99 mA - 104%/107% (100% = 15 mA)
NO shorts, leakage or gas. NO noise or microphonics.
Curve trace is also included in the original RoeTest report.
Appearance & cosmetic condition
Beside the world-class sound characteristics, we treasure this pair because the pristine condition the two tubes are in - nearly 100% of the paint is intact.
7L4 *9H (7L4 = change code, * = Amperex New York factory, 9 = 1959, H = August)
