Mullard M8136 / CV4003 (ECC82)
MILITARY GRADE | BOX ANODE | MADE IN GT. BRITAIN | MATCHED QUAD
Great Britain
Box Anode
“O” Getter
Up for sale is a premium matched quad (4 pieces) of Mullard M8136 / CV4003 vacuum tubes. These are the high-reliability military versions of the ECC82, featuring the specialized Box Anode structure and a clear glass envelope. Made in Great Britain, these tubes are legendary for their warm, musical “British sound” and exceptional structural integrity.
Precision tested on our Amplitrex AT1000 digital laboratory system, the results below utilize the Percentage Method against original factory design-center specifications (Ip = 10.5 mA / Gm = 2200 µMhos). This quad is exceptionally healthy and ideal for critical high-fidelity applications.
| Serial No. | Test Triode – T1/T2 | Parameter ip mAdc | Result ip mAdc | % Ip (Emission) | Parameter Gm uMhos | Result Gm uMhos | % Gm (Transc.) |
|---|---|---|---|---|---|---|---|
| #214153 | Triode 1 | 10.5 | 8.3 | 79.0% | 2200 | 1900 | 86.4% |
| Triode 2 | 10.5 | 7.1 | 67.6% | 2200 | 2130 | 96.8% | |
| #214062 | Triode 1 | 10.5 | 10.0 | 95.2% | 2200 | 1900 | 86.4% |
| Triode 2 | 10.5 | 8.3 | 79.0% | 2200 | 2100 | 95.5% | |
| #142631 | Triode 1 | 10.5 | 8.3 | 79.0% | 2200 | 1900 | 86.4% |
| Triode 2 | 10.5 | 8.0 | 76.2% | 2200 | 2100 | 95.5% | |
| #618567 | Triode 1 | 10.5 | 8.3 | 79.0% | 2200 | 1900 | 86.4% |
| Triode 2 | 10.5 | 8.3 | 79.0% | 2200 | 2200 | 100.0% |
⚠️ International Buyers: Custom duties and taxes are the responsibility of the buyer in their country.
Note: Extended area surcharges may apply for remote addresses; please confirm before checkout.
Quality Verified Since 1970
Specializing in thoroughly tested and screened quality vacuum tubes.
Testing equipment includes Amplitrex AT1000, Hickok 752a, and AVO Type 160.
Custom duties and taxes are the responsibility of the buyer in their country.
Support: [email protected] Precision Verified — NOS Audio Tubes
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