The 50C5 is a beam tetrode audio power valve designed to operate in equipment with a series heater chain and no mains transformer. It is an American design and consequently the typical voltages employed are 110 Volts.
With an anode load of 2,500Ω the 50C5 will generate 1.9 Watts at 9% total harmonic distortion.
The basic design of this audio valve was fitted with a number of different heaters: 12C5 - 12.6 V @ 0.6 A, 17C5 - 19.8 V @ 0.45 A, 25C5 - 25.0 V @ 0.3 A & 50C5 - 50.0 V @ 0.15 A. All of the variants are covered by the data-sheet.
The shaped anode is roughly oval in shape.
The GE logo. The bright beam forming plate can be seen through the notch at the top of the anode.
The thin glass tube envelope is 18 mm in diameter, and excluding the B7G base pins is 59 mm tall.