Sensibly equivalent¶ to:
The 7R7 is a screened pentode and double diode. This is the classic valve design for AGC rectification, signal detection and first audio amplifier. The 7R7 pentode is of the semi variable-μ type and thus can also function for IF amplification.
The type designation is etched into the envelope dome. There is no make identified.
The wide glass tube envelope is 29 mm in diameter, and excluding the B8B base pins is 55 mm tall.
References: Datasheet & 1040. Type 7R7 was first introduced in 1942.
Absolute Maximum Operating Conditions¶
Updated January 11, 2017. shape:wide.glass.tube construction:all.glass type:double.diode.pentode age:1940.1950 base:b8b heater:6.3v pins:8 pin:1.h pin:2.a pin:3.a(d2) pin:4.a(d1) pin:5.g2 pin:6.g1 pin:7.k pin:8.h