01-23-2014, 09:27 PM
For mica caps - they are never exposed to this kind of voltage, and a typical mica cap today is 2-3 bucks for 630V rated cap.
Your #73 and 74 are a bit different. Many folks will say you do need over a 1000V rating.
In a normally working radio I do not see the reason for it, the maximum voltage is your B+ which is usually 270V or so.
However the effect know as "flashover" does exist in tube amps and is usually the result of plugging and especially unplugging the speaker while hot and playing. This creates very high voltages and the cap may get a breakdown. If your speaker is soldered in and not pluggable, there is no reason to expect it, and 500-600V rating would be just fine.
Your #73 and 74 are a bit different. Many folks will say you do need over a 1000V rating.
In a normally working radio I do not see the reason for it, the maximum voltage is your B+ which is usually 270V or so.
However the effect know as "flashover" does exist in tube amps and is usually the result of plugging and especially unplugging the speaker while hot and playing. This creates very high voltages and the cap may get a breakdown. If your speaker is soldered in and not pluggable, there is no reason to expect it, and 500-600V rating would be just fine.
