05-11-2026, 10:53 AM
Roy,
I've been investigating the double pole double throw situation for switching between radio and Bluetooth for some time. I did it with a tiny AA5 and a tiny transformer to provide power to the BT. But I wanted something more integrated for my Philco 650X and the 37-630 I'll be restoring. So I think I will try disabling the 2-4 MHz band on the sets and use the band switching to disable the rf radio and turn on Bluetooth. That band has nothing on it anyway. Why not liven it up? And when the power supply for Bluetooth comes on it turns on a bright blue LED. I've looked at circuits in AM/FM sets and it appears to favor removing B÷ from one or all of the FM rf stages when switching to AM.
I've been investigating the double pole double throw situation for switching between radio and Bluetooth for some time. I did it with a tiny AA5 and a tiny transformer to provide power to the BT. But I wanted something more integrated for my Philco 650X and the 37-630 I'll be restoring. So I think I will try disabling the 2-4 MHz band on the sets and use the band switching to disable the rf radio and turn on Bluetooth. That band has nothing on it anyway. Why not liven it up? And when the power supply for Bluetooth comes on it turns on a bright blue LED. I've looked at circuits in AM/FM sets and it appears to favor removing B÷ from one or all of the FM rf stages when switching to AM.
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