11-02-2008, 01:58 AM
Hello M100C. A good way to sub for your open Spkr field-coil is by using a modern-type wirewound power resistor. According to Rons orig Philco Spkr data here, your orig spkr ( mod K-3) had a FC resistance of approx 3100 ohms.
Until you can find a orig replacement, or have your vintage spkr repaired, you could sub a 5 or 10 watt power resistor of approx 3K- to 3100 ohms as close as possible to 3100 ohms. You can trace back to your chassis orig spkr connection ,the correct 2-pins that originally used the spkr field, disconnect those 2 wires, then solder in the new ceramic wire-wound power-resistor across those 2 pins under chassis on the orig female-side of spkr connector. Since the orig spkr voice-coil was 0.7 ohms, using a modern pm type 8 ohm should work fine. Monitor the heat of the new power resistor if you decide to use one, as it will get hot which is normal in this case. The 5-watters usually are all I use, however the 10-watters will operate with less heat dissapated, but take up more space under the chassis.Hopefully, you can find a good orig spkr in the future if total "originality" is your preference. I have found the modern pm type full range spkrs usually sound much better overall anyways compared to the originals.Just my opinion though. Good luck with your vintage Philco restoration!
Until you can find a orig replacement, or have your vintage spkr repaired, you could sub a 5 or 10 watt power resistor of approx 3K- to 3100 ohms as close as possible to 3100 ohms. You can trace back to your chassis orig spkr connection ,the correct 2-pins that originally used the spkr field, disconnect those 2 wires, then solder in the new ceramic wire-wound power-resistor across those 2 pins under chassis on the orig female-side of spkr connector. Since the orig spkr voice-coil was 0.7 ohms, using a modern pm type 8 ohm should work fine. Monitor the heat of the new power resistor if you decide to use one, as it will get hot which is normal in this case. The 5-watters usually are all I use, however the 10-watters will operate with less heat dissapated, but take up more space under the chassis.Hopefully, you can find a good orig spkr in the future if total "originality" is your preference. I have found the modern pm type full range spkrs usually sound much better overall anyways compared to the originals.Just my opinion though. Good luck with your vintage Philco restoration!
