The N37 is a television type audio output pentode for use on a 300 mA heater chain.The load impedance is 6000 Ω and the cathode resistor is 330 Ω. At 10% total harmonic distortion the valve can produce 2.3 Watts of audio.
The red Marconi label covers most of the envelope circumference.The thin glass tube envelope is 17 mm in diameter and, excluding the B7G base pins, is 58 mm tall.References: Data-sheet & 1040. Type N37 was first introduced in 1950. See also 1950 adverts. |
Pin Connections
| 1 | 2 | 3 | 4 | 5 | 6 | 7 |  g1 | k | h | h | a | ic | g2 |
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Absolute Maximum Operating Conditions¶
| Vh | Ah | Va | Vs | Vg | mAa | mAs | ra | gm | 
| 13.0 | 0.3 | 165 | 165 | -11.4 | 29.0 | 5.4 | 23200 | 9.5 |
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Updated January 21, 2026.
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