Sensibly equivalent¶ to:
The DH63M is a double diode triode designed for receiver use. Diode detection and diode AGC rectification together with a triode for first audio voltage amplifier. A classic part of the Magic Three.
The M suffex denotes the external metallisation. The DH63 is a plain glass type.
The diodes would be for signal and AGC rectification and the triode would act as AGC amplifier or first audio amplifier.
The Osram brand and BVA.
The wide glass envelope is 29 mm in diameter and, excluding the IO base pins, is 87 mm tall.
References: Datasheet. Type DH63M was first introduced in 1937.
Absolute Maximum Operating Conditions¶
Updated March 12, 2014. shape:wide.glass.tube construction:pinch type:double.diode.triode age:1940.1950 base:io heater:6.3v pins:8 pin:1.m pin:2.h pin:3.a pin:4.a(d2) pin:5.a(d1) pin:6.nc pin:7.h pin:8.k pin:tc.g1