Sensibly equivalent¶ to:
815 QV04-20 VT-287
The QQV04-20 power VHF double tetrode is the valve that came before the QQV03-20. In this valve we see two independent electrode systems. This is the American pattern. In the later valves in this series from Mullard the European pattern of a single cathode assembly is developed. The twin valves in an envelope approach was harder to keep stable and required external neutralising capacitors.
The ratings presented are per valve with the exception of the heater parameters and the final output power available, which are for the pair operating together.
Originally the QQV04-20 was known as the QV04-20 and Mullard changed the nomenclature in December 1948.
Seen from the rear, the pressed box anodes are seen.
The wide glass tube envelope is 48 mm in diameter, and excluding the IO base pins, is 100 mm tall.
References: 1951 Datasheet, 4065 & 1040. Type QQV04-20 was first introduced in 1948.
Absolute Maximum Operating Conditions¶
PDF scanned from an original document held by the museum
Updated November 09, 2017. shape:wide.glass.tube construction:pinch type:double.beam.tetrode age:1940.1950 base:io heater:6.3v pins:8 pin:1.h pin:2.g1(2) pin:3.k.bp.s pin:4.g2 pin:5.hct pin:6.ic pin:7.g1(1) pin:8.h pin:tc.a(1) pin:tc.a(2)