Sensibly equivalent¶ to:
Type 6F6 is a general-purpose audio output pentode intended for domestic and car radios. It dates from the mid-1930s and was a well-established classic long before WWII. Its output is roughly similar to that of the well-known type 6V6 but it was considerably more sensitive and could be driven directly from the detector output, thus saving one stage of audio amplification. This was convenient particularly in compact car radios but the price of the extra gain was paid in a larger cathode and more heater power than the 6V6. As a result it tended to run hot and, in car radios, a derating was normally recommended.
The operating values given are for single ended use with an anode load of 7,000 Ohms.
If a pair are used as an audio amplifier in push pull class A, 10.5 Watts are possible with 3% distortion.
The equivalent type KT63 is a beam tetrode. Electrically identical types but on UX6 bases are the Type 42 with a 6.3 Volt heater and 2A5 with a 2.5 volt heater.
The RCA logo and the brand name Radiotron.
The thin metal tube envelope is 25 mm in diameter and, excluding the IO base pins, is 67 mm tall.
References: Data-sheet & 1040. Type 6F6 was first introduced in 1936.
Absolute Maximum Operating Conditions¶
Updated November 28, 2013. shape:thin.metal.tube construction:glass.disc type:pentode age:1930.1940 base:io heater:6.3v pins:8 pin:1.m pin:2.h pin:3.a pin:4.g2 pin:5.g1 pin:6.- pin:7.h pin:8.k