03-08-2010, 07:50 PM
This is a production change, documented in the 1941 RMS Year Book.
Models 41-280, Run 7; 41-285, Run 7; 41-287, Run 7, and 41-290, Run 5
To improve the Bass compensation action in the volume control circuit beginning with the above production run numbers, resistor (41) 33,000 ohms was changed to 100,000 ohms, Part No. 33-410339. Condenser (45) .01 mfds., 400 volts was also changed to .003 mfds., 1000 volts Part No. 30-4469.
There is no need to use a 1000 volt capacitor for part (45). 600 volts is overkill, but it is easier to standardize on 600/630 volt capacitors throughout when buying new caps.
Use of an .003 uF cap for part (45) will give your radio thundering bass. An .01 is too large here to be effective enough for bass compensation, thus the change.
I've modified a few Philcos that had 33K or smaller resistors and .01 uF caps in this circuit. I changed them to 68K and .0047 uF. Result: great bass response.
YMMV.
Models 41-280, Run 7; 41-285, Run 7; 41-287, Run 7, and 41-290, Run 5
To improve the Bass compensation action in the volume control circuit beginning with the above production run numbers, resistor (41) 33,000 ohms was changed to 100,000 ohms, Part No. 33-410339. Condenser (45) .01 mfds., 400 volts was also changed to .003 mfds., 1000 volts Part No. 30-4469.
There is no need to use a 1000 volt capacitor for part (45). 600 volts is overkill, but it is easier to standardize on 600/630 volt capacitors throughout when buying new caps.
Use of an .003 uF cap for part (45) will give your radio thundering bass. An .01 is too large here to be effective enough for bass compensation, thus the change.
I've modified a few Philcos that had 33K or smaller resistors and .01 uF caps in this circuit. I changed them to 68K and .0047 uF. Result: great bass response.
YMMV.
--
Ron Ramirez
Ferdinand IN
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