06-13-2008, 12:08 PM
I am working on restoring a 37-604. The schematic is not in Nostalgia Air, but the 604 is:
http://www.nostalgiaair.org/PagesByModel...013796.pdf
The filter choke, part 59 in the 604, has been replaced. The original was likely 50-60hy, 2250 ohms DC. The replacement is probably about 4-5hy and 235 ohms. The choke only feeds the 6A8. A close replacement is available from Hammond/AES etc.: 155C, 60hy, 8ma, 2750 ohms DC.
Since the original is gone, and a good replacement is installed, would it not be possible to simply add a series resistor to total about 2250 ohms and add a LARGER filter capacitor? The original was only 8uf. Since I have to recap anyway, why not just use a 22 or 47uf 160 volt?
I'm not sure what the original function of this choke was, but not may radios seem to use one in this position. Perhaps it has something to do with reduction of oscillator flutter or modulation hum?
Opinions welcome!
http://www.nostalgiaair.org/PagesByModel...013796.pdf
The filter choke, part 59 in the 604, has been replaced. The original was likely 50-60hy, 2250 ohms DC. The replacement is probably about 4-5hy and 235 ohms. The choke only feeds the 6A8. A close replacement is available from Hammond/AES etc.: 155C, 60hy, 8ma, 2750 ohms DC.
Since the original is gone, and a good replacement is installed, would it not be possible to simply add a series resistor to total about 2250 ohms and add a LARGER filter capacitor? The original was only 8uf. Since I have to recap anyway, why not just use a 22 or 47uf 160 volt?
I'm not sure what the original function of this choke was, but not may radios seem to use one in this position. Perhaps it has something to do with reduction of oscillator flutter or modulation hum?
Opinions welcome!
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
