01-26-2015, 05:28 PM
Let's examine your first question first. 
The .05 uF cap, part (20), is tied into the B+ line feeding the plate of the RF tube (through the appropriate coils, of course), and it looks to me that it acts as a bypass to keep stray RF out of the B+ line.
The second question is more tricky.
1000 volts were specified due to the possibility of voltage spikes at the plates of the audio output tubes. Now, there has been disagreement among experienced collectors/restorers as to whether they really need to be 1000 volts or not. All I can tell you is that I've been using 600/630 volt caps as these plate bypasses for years, and have yet to have one blow up on me. But then again, I do not run my radios at high volume levels. If you run a radio full blast, then it *might* need the 1000 volt rating. YMMV.
Just curious...why are you using a Canadian 37-3670 schematic? Although it should be the same as the USA 37-670 schematic, I think...
The .05 uF cap, part (20), is tied into the B+ line feeding the plate of the RF tube (through the appropriate coils, of course), and it looks to me that it acts as a bypass to keep stray RF out of the B+ line.
The second question is more tricky.
1000 volts were specified due to the possibility of voltage spikes at the plates of the audio output tubes. Now, there has been disagreement among experienced collectors/restorers as to whether they really need to be 1000 volts or not. All I can tell you is that I've been using 600/630 volt caps as these plate bypasses for years, and have yet to have one blow up on me. But then again, I do not run my radios at high volume levels. If you run a radio full blast, then it *might* need the 1000 volt rating. YMMV.
Just curious...why are you using a Canadian 37-3670 schematic? Although it should be the same as the USA 37-670 schematic, I think...
--
Ron Ramirez
Ferdinand IN
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