Matched Pair Philco Type / Number 27 #27 Vacuum Tubes Valves Black Plates 6AF4A 54 and 64 where minimum

54 and 64 where minimum (65%) is 50

engraved base number 78 tubes were tested on our Paul Hart-calibrated TV7/U for shorts

black plates and bottom

This new old stock-testing RCA 6CG7 / 6FQ7 dual triode tested a perfectly-balanced 2600/2600 micromhos on our Hickok 800

They measured 38

Matched Pair Philco Type / Number 27 #27 Vacuum Tubes Valves Black Plates 6AF4A 54 and 64 where minimumThis matched pair of Philco Type 27 triodes was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. Transconductance measured 35 for Tube One and 36 for Tube Two where minimum (65%) is 25 and 100% is 38. The tubes have rounded black plates; wire snubbers for increased rigidity and lowered microphonics; dimpled sheet getters; excellent flashing and well secured bases and bottles that are nice and