I made a video of the 866's in my Valiant glowing and dancing to the tune "CQSerenade" being fed into the mic (on dummy load of course). Turned out a waste of time as the 60Hz beating with the video refresh rate caused nothing but flutter. Something I should have known after 30 some years in television broadcast engineering.
Dave, VE1ADH ----- Original Message ---- From: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> To: [email protected] Sent: Sunday, March 30, 2008 6:01:29 AM Subject: AMRadio Digest, Vol 50, Issue 40 Send AMRadio mailing list submissions to [email protected] To subscribe or unsubscribe via the World Wide Web, visit http://mailman.qth.net/mailman/listinfo/amradio or, via email, send a message with subject or body 'help' to [EMAIL PROTECTED] You can reach the person managing the list at [EMAIL PROTECTED] When replying, please edit your Subject line so it is more specific than "Re: Contents of AMRadio digest..." Today's Topics: 1. Re: Loudenboomer MK2 hv supply tubes (D. Chester) ---------------------------------------------------------------------- Message: 1 Date: Sat, 29 Mar 2008 12:52:57 -0500 From: "D. Chester" <[EMAIL PROTECTED]> Subject: Re: [AMRadio] Loudenboomer MK2 hv supply tubes To: <[email protected]> Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original If the power supply is designed to use 866A's, don't worry about using 3B28's; they will work just as well. They are exact replacements, and tend to give less trouble than the MV tubes, even though they don't have the pretty blue glow. If you look closely in dim light, you can see a violet glow deep inside the plate structure. Likewise, the 4B32 is a direct replacement for the 872A. The 3B28 and 4B32 use xenon gas instead of mercury as the ionising medium. Of course, solid state replacements will also give identical performance. Mercury, xenon and solid state rectifiers all have a fixed voltage drop that is insignificant in HV applications. High vacuum tubes have a substantial voltage drop at normal operating current. There is a high-vacuum version of the 866A, the 836. I'm not sure if it has as high a p.i.v. rating as the 866A, or if it is more like the old 866 that had only 7.5 kv piv instead of the 10kv rating of 866A's and 872A's, 3B28's and 4B32's. I have found the best on-line source for tube info in Frank's Electron Tube Data sheets at http://tubes.mkdw.net/index.html. For some reason, the USA link is dead, but any of the other links will work, and they all have identical data. I usually click on the Australian one. You can find data on obscure tubes such as subminiatures, European types and special military types. On most tube types there are multiple data sheets of data published by different manufacturers, which sometimes gives you more information than books like the RCA, GE or Eimac manuals. Don k4kyv ------------------------------ ______________________________________________________________ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected] End of AMRadio Digest, Vol 50, Issue 40 *************************************** __________________________________________________________________ Ask a question on any topic and get answers from real people. Go to Yahoo! Answers and share what you know at http://ca.answers.yahoo.com ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/[email protected]/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected] To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
