The 6DY7 is an audio output double beam tetrode designed for stereo amplifiers. The construction uses frame grids for both g1 and g2 and they are aligned to minimise the screen current.
These are rare valves and do not appear to have been used in many commercial designs.
The wide glass tube envelope is 39 mm in diameter, and excluding the IO base pins is 84 mm tall.
References: Datasheet, 1040 & 1043. Type 6DY7 was first introduced in 1958.
Absolute Maximum Operating Conditions¶
Updated February 27, 2014. shape:wide.glass.tube construction:glass.foot type:double.beam.tetrode age:1950.1960 base:io heater:6.3v pins:8 pin:1.g1(2) pin:2.h pin:3.a(2) pin:4.g2 pin:5.g1(1) pin:6.a(1) pin:7.h pin:8.k.bp