The Osram HL.8 (Hpoint8) is an early mains heated valve. This exhibit has a Shaw UV plated nickel base shell. The data-sheet shows the valve with a standard B4 base.
The very low heater voltage of 0.8 Volts was chosen to minimise hum on this directly heated valve. The design use was as a detector, HF or AF amplifier.
The etched identification for the Osram logo and the BVA logo. The location pip for the UV bayonet base is left of centre on the base shell.
The Type designation is etched into the dome.
The electrodes are mounted horizontally and a diagram of the internal construction can be found on the data-sheet.
The Shaw base with MOV stamped onto the insulating filler.
The balloon envelope is 46 mm in diameter and, excluding the UV base pins, is 95 mm tall.
References: Data-sheet. Type HL.8 was first introduced in 1925. See also1925 adverts.
