I could not find a tube datasheet for a 12SB7 but here is a link for the 6SB7Y http://www.mif.pg.gda.pl/homepages/frank/sheets/049/6/6SB7Y.pdf Wayne WB5WSV -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mailman.qth.net/pipermail/arc5/attachments/20160404/6509d80a/attachment-0001.html>