12-19-2016, 10:33 AM
Hello Rick,
The NEW metal tubes were introduced around 1936 and sets designed to use these tubes grounded pin 1 of the socket, which was connected to the metal shield around the tube. In situations where RF signals are present, such as the RF amplifier or converter or IF amplifier, leaving this pin ungrounded can cause the set to oscillate or poor reception. I had someone bring me a Zenith set once with this issue. It was designed for the G suffix tubes with a tube shield and someone had put a metal tube in as a replacement. I think it was a 6K7. By grounding pin 1, the set performed wonderfully. As the 5Y4 is a rectifier, it's not likely that leaving this pin ungrounded will cause many issues.
The NEW metal tubes were introduced around 1936 and sets designed to use these tubes grounded pin 1 of the socket, which was connected to the metal shield around the tube. In situations where RF signals are present, such as the RF amplifier or converter or IF amplifier, leaving this pin ungrounded can cause the set to oscillate or poor reception. I had someone bring me a Zenith set once with this issue. It was designed for the G suffix tubes with a tube shield and someone had put a metal tube in as a replacement. I think it was a 6K7. By grounding pin 1, the set performed wonderfully. As the 5Y4 is a rectifier, it's not likely that leaving this pin ungrounded will cause many issues.
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
