<html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=utf-8"><meta name=Generator content="Microsoft Word 15 (filtered medium)"><style><!--
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--></style></head><body lang=EN-US link=blue vlink="#954F72"><div class=WordSection1><p class=MsoNormal>It was cost. 1619 tubes were very cheap, maybe 25 cents surplus. Seeburg Corp who made jukeboxes was running short of the four 6V6 tubes for their jukeboxes due to the Korean war using the available 6V6s in 1951 so they ran a production run of modified amps using four 1619’s with a 2.5 volt filament transformer for the filaments. Most early 50’s Heath equipment used WWII surplus parts. </p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Fred WA3KIO</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Sent from <a href="https://go.microsoft.com/fwlink/?LinkId=550986">Mail</a> for Windows 10</p><p class=MsoNormal><o:p> </o:p></p><div style='mso-element:para-border-div;border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal style='border:none;padding:0in'><b>From: </b><a href="mailto:larrysheldon@cox.net">Larry Sheldon</a><br><b>Sent: </b>Saturday, October 21, 2017 9:34 PM<br><b>To: </b><a href="mailto:heath@puck.nether.net">heath@puck.nether.net</a><br><b>Subject: </b>Re: [Heath] PS-3 Power Supply</p></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>On 10/21/2017 19:32, Wilson Lamb wrote:</p><p class=MsoNormal>> I have just recovered a derelict PS-3 power supply.</p><p class=MsoNormal>> Interesting old circuit, with 1619 pass tubes.</p><p class=MsoNormal>> Does anyone know why they used the 1619, which is a 6L6 with no cathode, just filaments?</p><p class=MsoNormal>> Is there any reason 6L6s would not work, except for filament voltage?</p><p class=MsoNormal>> I have some 1619s coming, but inquiring minds want to know...</p><p class=MsoNormal>> WL</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Cheaper to make by the cost of the cathodes and their installation?</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>-- </p><p class=MsoNormal>"Everybody is a genius. But if you judge a fish by</p><p class=MsoNormal>its ability to climb a tree, it will live its whole</p><p class=MsoNormal>life believing that it is stupid."</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>--Albert Einstein</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal> From Larry's Cox account.</p><p class=MsoNormal>_______________________________________________</p><p class=MsoNormal>Heath mailing list</p><p class=MsoNormal>Heath@puck.nether.net</p><p class=MsoNormal>https://puck.nether.net/mailman/listinfo/heath</p><p class=MsoNormal><o:p> </o:p></p></div></body></html>