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DL73Sensibly equivalent¶ to:See also:
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The DL73 is a dry battery output pentode. It is similar to the DL71 and DL72 hearing aid output valves but delivers a significantly greater output. The anode resistance of 16,000 Ohms is only 10% of the other similar valves but audio is not the main application unless as a modulator.The DL73 is also specified for use as a VHF transmitter power amplifier. One Watt does not seem much but at 200 MHz would have a range of a few miles in an urban environment and in open country a few tens of miles with an efficient aerial. As a personal radio with a whip aerial the range would be much less but still useful.
The screen and control grids can be seen but not clearly. The screen grid is wound at a slightly wider pitch and with slightly thicker wire than the control grid. The thin glass tube envelope is 10 mm in diameter, and excluding the B8D base pins is 43 mm tall.References: Data-sheet & 1040. Type DL73 was first introduced in 1957. See also 1957 adverts. |
Pin Connections
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |  ic | g1 | nc | f-,g3 | f+ | nc | a | g2 |
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Absolute Maximum Operating Conditions¶
| Vh | Ah | Va | Vs | Vg | mAa | mAs | ra | gm | 
| 1.25 | 0.2 | 100 | 100 | -9 | 15 | 3.8 | 16,000 | 2.5 |
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Absolute Maximum Operating Conditions¶
| Vh | Ah | Va | Vs | Vg | mAa | mAs | Pdiss | Pout | freq | 
| 1.25 | 0.2 | 150 | 75 | -2 | 18.6 | 5.6 | 2.0W | 1.2W | 200 |
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Updated January 04, 2022.
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