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Title: Cathode Modulating 2x 810's Post by: W4RFM on November 03, 2020, 04:32:45 PM So I am looking at an old copy of QST, April 1940 to be exact, and I see this. What are your thoughts and opinions?
(https://i.postimg.cc/yxwtjmLs/RCA-810-Cathode-2.jpg) Interesting that the mod iron impedance is almost exactly that of a Heathkit Apache 11K / 3K. I just checked (the Bay) and 809's are still available, although i am sure a later /better pair of tubes could be used. 810's are there also but both types are a little spendy, for my taste. Title: Re: Cathode Modulating 2x 810's Post by: WD5JKO on November 04, 2020, 08:19:39 AM good reference thread on CM: http://amfone.net/Amforum/index.php?topic=45471.0 |