Vintage Valves
< 'R' valve (1922) The first type of triode which was widely used. Thin wire filament
is suspended inside helical wire grid, inside tubular anode.
> Marconi DEV triode (1924). designed for low capacitance to improve high-frequency performance in short-wave radio applications
< Ediswan AR (1922), Cossor P2 (1922). Cosmos SP18 (1925). The Cossor device used an
unusual 'hat' construction to avoid infringing patents which specified tubular electrodes.
This construction can also be seen in the Cossor 610FP, right. Cossor
610FP data
< Radiotron UV202 transmitting valve (1921). Marked ' Licensed
for Amateur or Experimental Use Only'
> GEC DET18 and Eimac 35T, very similar construction despite being made on opposite sides of the Atlantic. I've found no reference to either of these in any of my books.
This info from Manuel Carbonell : 35T: Equivalent to 3-50A4.. High mu triode,
oscilator, class-B modulator or low frequency amplifier, class-C buffer, doubler or
amplifier.
Plate power: 35 W (max). Plate voltage: 1500 V (max). Maximum frecuency: 100 MHz.
From Ron Pond : The DET18 was used as a class C unmodulated amplifier ( Telegraphy)
Filament Voltage; 5.0@ 4A
Anode Voltage; 1000 @ 100Ma
gm. ; ( uA/V ) 2550
Max Freq; 100MHz
< DeForest 'Audion' DL14 Low Mu Amplifier (1927).
> Tetrode with side terminal, Philco 43 Pentode (1931)
< Two valves with angled electrode assemblies, left
one unmarked, right STC 'Micromesh' R3 indirectly heated full-wave rectifier
(1932).
> VT121 triode, possibly designed for telecom repeater applications, as
it's marked 'GPO' (general post office)
< German WW2 military valves - Valvo RL12 P10, Telefunken LS50.
> Ediswan ESW20
< German WW2 valves by Telefunken - RV12P2001, RV12P3000, LV1, LG1
I currently have 3 valves like the first
two of these on ebay
Marconi-Osram LS2 triode.