1L4 single vacuum-tube radio

I made some radio by 12V. Some of receiving tube can be used by 12V-DC on its plate voltage. One day I bought a special valve named 1L4. See fig 2! It is made to use by the battery. I tried to use it by special low voltage on its plate. But it cannot work under 12V. Therefore I decided to use it as the diode. See fig 1! I made “Germanium radio" by this valve. This MW radio has a dual detector. 1L4 diode has 3dB lower efficiency than 1N60. But I can hear some broadcasting station by it. Audio signal of 7-pin (+terminal of the heater) is stronger than 1-pin (-terminal of the heater). This is described on old textbook of valve radio. Think the reason of it! I can enjoy thinking about it. I may be the last human kind who tested this theory. HiHi

1L4 シングル真空管ラジオ




Fif2: The standard usage of 1L4 and bottom view (pin use)


name: 1L4 Sharp cutoff pentode
Firament : 1.4V 0.05A
Usage : RF-AMP
Plate voltage : 90V
Control grid : 0V
Screen grid : 90V,2mA
Plate current : 4.5mA
Rp : 350k ohm プレート内部抵抗
gm : 1025 u moh ( micro Siemens )相互コンダクタンス1025μモー

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