Antique radios, Old Time Radios
SP18
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Country:
Great Britain (UK)
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|
| Identical to |
SP18
|
| Similar
Tubes |
Normally replaceable-slightly different:
SP18/B
; SP18/G
; SP18/R
Other base:
SP18_UX
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| First year |
1925
Saga of the Vacuum Tube, Tyne page 373
|
| First Source
(s) |
1925 : History of the British Radio Valve to 1940 p.157
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| Base |
Europe 4-Pin B4 (Eu A, E, 4A) 1914
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| Was used by |
Radio/TV-reception etc. |
| Filament |
Vf 1.8 Volts / If 0.3 Ampere / Direct / Battery = |
| Description |
This SP18 without dot or suffix (B, G, R) is definitely existing (see photo).
Shortpath is a Cosmos brand, see Keith R. Thrower, British Radio Valves, page 48. Probably an anglicised version of the WD11 from the USA.
According to Tyne (pp.373, 374) there are three variants:
- SP18/R (1925)
- SP18/G (1925)
- SP18/B (1926)
in the Benjamin Catalog all SP18 are tubular, although Tyne shows an SP18/G having a globe shape. Error?
The SP18/G or Green spot was selected as a general purpose hf and af tube for RC coupling. The SP18R or red spot was selected with a lower Ra for output operation and had a gm of 0.9 to 1.0 mA/V.
The advertised price in 1925 for red and green spots was 12/6 = 0.63GBP
Story of Cosmos valves see here
Text in other
languages (may
differ)
|
| Tube prices |
2 Tube prices (visible for members
only)
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| Information source |
Wireless World (The), London (WW, 79) Advertisement by Metro-vick Dec 1925
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SP18: KoBi
Konrad Birkner † 12.08.2014
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Just Qvigstad
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SP18: Banneitz, TB der drahtl. Teleph. 1927
Anonymous 15 Collector
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Quantity of Models at Radiomuseum.org with this tube (valve, valves, valvola, valvole, válvula, lampe):3
Collection of
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