BRIMAR CV4003 – Premium MATCHED QUAD
GRADE: PLATINUM GRADE TUBES | VINTAGE MILITARY SPEC BRITISH DUAL TRIODES IN ORIGINAL BOXES
Brimar CV4003 / 12AU7 / ECC82
Top Ring Getter
Grey Plate
Chrome Dome
Original Brimar Boxes
Amplitrex AT1000 Tested
Up for sale is a rare, ultra-premium matched quad (4 Pcs) of vintage military-grade NOS Brimar CV4003 / 12AU7 / ECC82 dual triode vacuum tubes, complete in their original Brimar red and yellow boxes. Manufactured in England, these high-reliability tubes feature a top ring getter, grey plates, and heavy silvered chrome domes. The British military CV4003 is widely considered one of the absolute finest 12AU7 variants ever produced, prized for its exceptionally low microphonics, lush midrange, deep dimensional soundstage, and extreme longevity.
As shown, all four 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. 807656 | Triode 1 (T1) | 10.5 mA | 11.6 mA | 110% | 2200 µMhos | 2300 µMhos | 105% |
| Triode 2 (T2) | 10.5 mA | 11.4 mA | 109% | 2200 µMhos | 2300 µMhos | 105% | |
| SR.NO. 807642 | Triode 1 (T1) | 10.5 mA | 11.2 mA | 107% | 2200 µMhos | 2300 µMhos | 105% |
| Triode 2 (T2) | 10.5 mA | 11.6 mA | 110% | 2200 µMhos | 2300 µMhos | 105% | |
| SR.NO. 807662 | Triode 1 (T1) | 10.5 mA | 11.8 mA | 112% | 2200 µMhos | 2300 µMhos | 105% |
| Triode 2 (T2) | 10.5 mA | 11.4 mA | 109% | 2200 µMhos | 2300 µMhos | 105% | |
| SR.NO. 807658 | Triode 1 (T1) | 10.5 mA | 11.2 mA | 107% | 2200 µMhos | 2300 µMhos | 105% |
| Triode 2 (T2) | 10.5 mA | 11.2 mA | 107% | 2200 µMhos | 2300 µMhos | 105% | |
Technical Note: Custom duties and taxes are the responsibility of the buyer in their country.
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nosaudiotubes (store manager) –
What beautiful tubes. It is better than my previous Apos Ray 12AU7 Select pair. Lower microphonics,lower noise floor and denser sound 👌👌
Very strong matching
Kunal Shrivastava