The 142BT is a beam tetrode audio output valve designed for use in universal sets without a mains transformer. The heater is designed to draw 200 mA at approximately 14.0 Volts and be connected as part of a heater chain across the mains supply either AC or DC.
The 142BT would produce 2.0 Watts at 8% distortion. Anode load to be 5,500Ω and the cathode resistor to be 265Ω
See also 202STH for the box for this exhibit.
Thanks to Alan Stepney for the images.
The classic envelope is 42 mm in diameter, and excluding the IO base pins is 99 mm tall.
Absolute Maximum Operating Conditions¶
Updated June 06, 2012.