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Philco 20A - Electronic Restoration Questions
#15

When this radio was made, large value capacitors were physically large and expensive. Radio manufactures tried to use the lowest value capacitors they could get by with. One of the tricks Philco used was to use a specific value capacitor in parallel with a choke to create a tuned circuit to filter the hum. The problem with that is, if the value of the capacitor is either too high or too low, it can actually increase the hum. Some may disagree, but I think it best to omit this capacitor and increase the value of the second filter to compensate. It is not a good idea to increase of the first filter because this will increase the B+ voltage.

Steve

M R Radios   C M Tubes


Messages In This Thread
RE: Philco 20A - Old cap can caps - by morzh - 08-09-2017, 08:03 PM
Capacitors for Philco Model 20 - by MrGrnEgz - 08-09-2017, 11:12 PM
RE: Capacitors for Philco Model 20 - by MrGrnEgz - 08-10-2017, 09:50 AM
RE: Capacitors for Philco Model 20 - by MrGrnEgz - 08-10-2017, 02:46 PM
RE: Capacitors for Philco Model 20 - by MrGrnEgz - 08-10-2017, 03:27 PM
RE: Capacitors for Philco Model 20 - by Steve Davis - 08-10-2017, 09:56 PM
RE: Capacitors for Philco Model 20 - by MrGrnEgz - 08-11-2017, 05:26 AM
Model 20A Frequency Indicator - by MrGrnEgz - 08-11-2017, 05:38 AM
Model 20A Power Cord - by MrGrnEgz - 08-12-2017, 01:18 PM
RE: Model 20A Power Cord - by Radioroslyn - 08-12-2017, 01:28 PM
Model 20A Speaker Cone Repair - by MrGrnEgz - 08-13-2017, 09:41 PM
AUX audio input for model 20A - by MrGrnEgz - 08-13-2017, 10:54 PM
RE: Model 20A Speaker Cone Repair - by MrGrnEgz - 08-14-2017, 08:50 AM
RE: Model 20A Speaker Cone Repair - by morzh - 08-14-2017, 04:48 PM



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