The Y61 is a magic eye tuning indicator. Construction follows the usual pattern with the triode voltage amplifier above the pinch and the display viewed through an end window.
The screen is circular and the central electrode is covered by a small black cap. The full display range is given for a 22 Volt alteration in grid voltage.
The general construction with the anode of the amplifier connected to the control electrode in the bowl.
The flat control electrode is at the top of the opening at the base of the bowl.
The wide glass envelope is 28 mm in diameter and, excluding the IO base pins, is 87 mm tall.
Reference: 1040. Type Y61 was first introduced in 1939. See also1939 adverts.
