02-11-2018, 10:56 AM
In the UK the PL84 power pentode is known for it's role as the frame output valve in TV receivers equipped with 110degree CRTs. In fact the PL84 was introduced in 1956 three years before the introduction of the 110degree CRT into Europe and the UK. Philips used two PL84s in a transformerless sound output stage in several continental TV sets.
From r-type.org: http://www.r-type.org/articles/art-146.htm
Heater voltage and current apart the characteristics of the PL84 are similar to the EL86.
The Philips K4 colour TV set also has a transformerless sound output stage. In this receiver the valves employed are a PCL86 and a PCL85
designed as a video output valve the PCL84 can be considered suitable as an audio output valve. Sobell and GEC used the PCL84 in the sound output stage in many TV receivers.
Philips used the EL81 in an audio amplifier. PL81 is becoming scare so best used for it's prime purpose as a television line output valve.
Geordie McBoyne.
From r-type.org: http://www.r-type.org/articles/art-146.htm
Heater voltage and current apart the characteristics of the PL84 are similar to the EL86.
The Philips K4 colour TV set also has a transformerless sound output stage. In this receiver the valves employed are a PCL86 and a PCL85
designed as a video output valve the PCL84 can be considered suitable as an audio output valve. Sobell and GEC used the PCL84 in the sound output stage in many TV receivers.
Philips used the EL81 in an audio amplifier. PL81 is becoming scare so best used for it's prime purpose as a television line output valve.
Geordie McBoyne.
