Matched Pair National Union NU Number / Type 76 #76 Vacuum Tubes Valves 7AH7 Sylvania new in box Sylvania 25Z5

new in box Sylvania 25Z5 tubes tested to spec on our Paul Hart-calibrated TV7/U

noise or gas and it tested as follows:

They measured (from left to right) 27/26

I am playing them in my Sound Craftsmen RC-2 monoblocks at 6

Matched Pair National Union NU Number / Type 76 #76 Vacuum Tubes Valves 7AH7 Sylvania new in box Sylvania 25Z5This matched pair of National Union type 76 triodes was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. Transconductance measured 49 for Tube One and 52 for Tube Two where minimum (65%) is 36 and 100% is 55. These tubes have shiny, dark gray, rounded plates; crenelated, top, rectangular mica and smooth rectangular bottom spacers and excellent flashing. I have played them in my Radio Craftsmen