Summary
6.3V indirectly heated cathode, manufactured 1948-1960. The 7W7 is a high gain sharp cut-off pentode. Electrically the same as the 7V7 but with slightly different pin connections.
The Tung-Sol data for this valve indicates that it is suitable for high gain narrow band amplifier service whereas the 7V7 is suitable for high gain wide band amplifier service.
The main distinguishing physical features are that the 7W7 has two cathode connections whereas the 7V7 has only one and has a separate shield pin.
The only significant electrical difference (based on the published data) is the grid-plate capacitance. For the 7V7 it is 0.004pF (4.0fF) and for the 7W7 it is 0.0025pF (2.5fF). The smaller grid-plate capacitance allows the use of higher load impedance, characteristic of narrow band amplifiers, without producing instability.
Physical Description
Tubular glass bulb on loctal base.
More Information
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Collection Names
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Collecting Areas
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Acquisition Information
Unknown Acquisition Method from Unknown Source, 1981
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Date Manufactured
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Inscriptions
Top of bulb: 7W7 Paper label on bulb: 7W7
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Classification
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Category
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Discipline
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Type of item
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Overall Dimensions
67 mm (Length), 30 mm (Outside Diameter)
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Keywords