Pentagrid Converter
The 12SA7Y Vacuum Tube is a metal type used as a converter
in AC/DC receivers.
12SA7 and 12SA7GT are interchangeable although there is a
slight wiring difference. The outer grid is connected to
a different pin. Each of these pins will be ground or
near ground. I haven't come across a radio where
interchanging these two styles of tubes cause a problem.
Trimmers do need to be adjusted.
12SA7Y has a low loss base. Look under the base. The base
material will be yellow/brown rather than black. May
require trimmers to be touched up but tubes are
interchangeable. At higher frequencies 12SA7Y should be
better. They require an octal socket.
Electrical Data
Heater Voltage ................................ 12.6 V
Heater Current .............................. 0.15 A
Preferred Substitutes .............. 12SA7,
12SA7GT, 12SY7