06-21-2011, 01:00 PM
Chris,
Make sure that if you decide to use the metal 6H6 detector tube that pin 1 on the tubes' socket is used only for a ground connection and not a tie point for other circuitry. The metal envelope of metal encased tubes act as the shield and their pin 1 is normally tied internally to the metal shield therefore pin 1 on the socket should be ground. On glass envelope tubes such as a 6H6G or 6H6GT pin one may not have been ground but used as a chassis tie point for other components. Glass tubes as you can see often use external metal shields to suppress oscillations and intermodulation effects, etc. Hopefully, whoever changed this tube out looked at this aspect? To my knowledge Philco did not use metal
tubes prior to WWII? If you decide to restore this set to original you may want to install a glass 6H6GT and find a metal shield...it's up to you of course. Glass 6H6GT tubes are not expensive and may be found from many suppliers.
Best wishes on you radio restore.
John
Make sure that if you decide to use the metal 6H6 detector tube that pin 1 on the tubes' socket is used only for a ground connection and not a tie point for other circuitry. The metal envelope of metal encased tubes act as the shield and their pin 1 is normally tied internally to the metal shield therefore pin 1 on the socket should be ground. On glass envelope tubes such as a 6H6G or 6H6GT pin one may not have been ground but used as a chassis tie point for other components. Glass tubes as you can see often use external metal shields to suppress oscillations and intermodulation effects, etc. Hopefully, whoever changed this tube out looked at this aspect? To my knowledge Philco did not use metal
tubes prior to WWII? If you decide to restore this set to original you may want to install a glass 6H6GT and find a metal shield...it's up to you of course. Glass 6H6GT tubes are not expensive and may be found from many suppliers.
Best wishes on you radio restore.
John
