CHELMER VALVE CO. EF86 / CV2901 – MATCHED PENTODE PAIR (2 PCS)
Clear Glass Envelope
Top Plate Getter
Internal Cage Shield Structure
Military Spec EF86 / CV2901 / 6267
New in Original Box
Amplitrex AT1000 Tested
Up for sale is a matched pair (2 pcs) of vintage NOS Chelmer Valve Co. EF86 / CV2901 low-noise audio pentode vacuum tubes, complete with their original CVC factory boxes[cite: 17]. Constructed with clear glass envelopes, internal mesh cage shielding, and top plate getters[cite: 17], these military-grade CV2901 spec valves are celebrated for high gain stability, low noise operation, and excellent rejection of microphonics. An outstanding matched pair upgrade or replacement for Vox AC15/AC30 V1 channels, high-end tube preamplifiers, and vintage studio condenser microphone circuits.
Both tubes have been fully tested on a precision Amplitrex AT1000 tube tester[cite: 17]. Measured Plate Current (Ip in mA) and Mutual Conductance (uMhos) alongside percentage performance ratings relative to nominal factory reference specs (Reference: 3.0 mA / 1,800 uMhos) are detailed in the table below.
| Serial No. | Tube Section | Plate Current (Ip) | Mutual Conductance (uMhos) | ||||
|---|---|---|---|---|---|---|---|
| Ref Spec | Result | % Ip | Ref Spec | Result | % uMhos | ||
| SR.NO:923005 | Single Pentode | 3.0 mA | 2.6 mA | 87% | 1800 | 1900 | 106% |
| SR.NO:923008 | Single Pentode | 3.0 mA | 2.7 mA | 90% | 1800 | 1900 | 106% |
Technical Note: Custom duties and taxes are the responsibility of the buyer in their country.
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