Sensibly equivalent¶ to:
The DH149 is a double diode triode, and no specific design use is quoted. Normally such a valve would be used as signal and AGC detector plus first audio amplifier stage in broadcast receivers. This valve is unusual in that the anode impedance is high, maybe this valve was to be used for video demodulation and amplification.
The 7C6 is an equivalent but the pin connections are slightly different in that pin4 is acknowledged to be a cathode connection.
The wide glass tube envelope is 28 mm in diameter and, excluding the B8B base pins, is 54 mm tall.
References: Datasheet & 1040.
Absolute Maximum Operating Conditions¶
Updated February 21, 2014.