02-06-2022, 07:00 PM
Sometimes manufacturers of AC/DC radios used bypass capacitors which were designed to be series resonant at the 455kc IF frequency. They were used to AC ground circuit common (which was connected to one side of the AC line) to chassis ground. This type of cap will have a very low AC impedance at the IF frequency and therefore make an excellent bypass.
Philco did something similar by wrapping turns of insulated wire around a regular paper bypass cap.
Typically you can replace the special cap with a similar value modern film cap, but you may have to experiment if you run into problems with squeals, or oscillations of the IF stage.
Philco did something similar by wrapping turns of insulated wire around a regular paper bypass cap.
Typically you can replace the special cap with a similar value modern film cap, but you may have to experiment if you run into problems with squeals, or oscillations of the IF stage.
