Sylvania JHS military spec 12au7 Blackplate with angled square getter Circa 1950's

From my personal collection ,as I need to cull the herd. Very rare and fantastic sounding, military spec sylvania black plates from the 1950's. These all test at or beyond new. The 50's production black plates are sublime sounding tubes, and will shine in any application. In this condition, get them while you can. All conditions firm, PayPal add 4%, Price is per pair

All tubes are tested on 2 different and very accurate mutual conductance testers with no bloated or just plain made up results, with tubes especially, do not lose sight of the fact that most often, you get what you pay for. Tubes will be packed tightly and safely; look to my other classifieds for other fine vintage tubes, and be sure to drop me an email with any questions, or inventory needs, thanks