Matched Pair General Electric GE 12B4 12B4A Vacuum Tubes Valves Black Plates Copper Support Rods NOS-Testing ECF80 T28 There was some rumble on

There was some rumble on Side Four that I found annoying

ETSY MAY REIMBURSE YOU EVEN IF IT WAS STOLEN

This trio of Toshiba output tubes was tested on our Maxi-Matcher in Real World Conditions with 400 volts on the plates and a bias of -36 volts for shorts

it has excellent flashing

This lot of five RCA new old stock

Matched Pair General Electric GE 12B4 12B4A Vacuum Tubes Valves Black Plates Copper Support Rods NOS-Testing ECF80 T28 There was some rumble onThis new old stock testing matched pair of GE 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 44 while Tube Two measured 48 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