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Title: Screen Mod 4D32 pair with 6Y6's. Post by: WA4WAX on May 20, 2017, 04:22:43 PM See page 110 in magazine and/or pdf reader. Comments and suggestions?
http://americanradiohistory.com/Archive-Radio-News/40s/Radio-News-1949-06-R.pdf Title: Re: Screen Mod 4D32 pair with 6Y6's. Post by: WA4WAX on May 20, 2017, 05:46:32 PM An update by the same author.
http://www.americanradiohistory.com/Archive-Radio-News/50s/Radio-News-1950-09-O.pdf Pages 95 and 94 on your pdf. They got scanned out of sequence. What can I say.....it looks cheap and easy. Title: Re: Screen Mod 4D32 pair with 6Y6's. Post by: Opcom on May 20, 2017, 09:07:02 PM The way the negative and positive excursions on the screen are limited gives promise to high modulation. The 6Y6 or substituted tube's peak plate voltage rating may be the limiting factor on the final amp screen voltage. The 6Y6 may have been chosen because it has a good size cathode and good cathode current ratings of 60-66mA according to the books plus it does not need a lot of drive voltage. It's also pretty inexpensive. The author talks about compression. It is not clear how gentle it is but it looks like the 6SQ7 diodes are part of the limiter. It looks like a great project to try.
Title: Re: Screen Mod 4D32 pair with 6Y6's. Post by: WA4WAX on May 21, 2017, 08:05:41 AM Dear Patrick: AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
Here is an idea: Use 6336, 6080, or better yet, Russian 6C33C instead of 6Y6. Connect the two triodes in parallel. That would be rather low plate resistance, and the power handling would be impressive. For the amp, use a pair of 813 with 1500 VDC on plates. Screen would be around 300 to 350 VDC, which would be well within the handling limits of these tubes. That would be a pretty hefty signal. |