Sensibly equivalent¶ to:
The PL504 is a purpose designed television pentode line output valve. It was introduced as a replacement for the PL500 and here we have an exhibit branded as Pinnacle with a different logo to PL504.
The peak anode voltage is quoted as 7,000 Volts and shows why the line output stage of a television receiver was the last consumer electronics product to remain a valve. The CRT excepted of course.
TV line output valves found their way into amateur radio transmitters for service at HF (up to 30 MHz) because of their peak voltage characteristics and relatively high current capability.
The construction is as a beam tetrode and the bright beam plate can be seen within the anode.
The wide glass tube envelope is 28 mm in diameter, and excluding the B9D base pins, is 92 mm tall.
References: Datasheet & 1040. Type PL504 was first introduced in 1961.
Absolute Maximum Operating Conditions¶
Updated January 12, 2016.