Matched Pair RCA 12B4 12B4A Vacuum Tubes Valves Black Plates Copper Support Rods NOS-Testing January 10 2021 Bottles: medium height

Bottles: medium height

new in box milspec Sylvania JHS-5977 tubes in this lot

I would rate it a 6

It has an engraved / stamped base

Matched Pair RCA 12B4 12B4A Vacuum Tubes Valves Black Plates Copper Support Rods NOS-Testing January 10 2021 Bottles: medium heightThis new old stock testing matched pair of RCA 12B4A tubes was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. Tube One measured 43 while Tube Two measured 46 where minimum (65%) is 32 and 100% is 49. Wish I could tell you how they sound, but I don't have any equipment that uses these. WE HAVE SCORES OF THOUSANDS OF VACUUM TUBES. IF IT'S NOT LISTED, WE MAY HAVE IT. PLEASE ALSO SEE OUT ETSY