General Electric GE 12AT7 ECC81 6679 Vacuum Tube Premium NOS NIB Hot-Stamped Bases Tube One measured 73/74 while

Tube One measured 73/74 while Tube Two measured 78/75 where minimum (65%) is 50/50 and 100% is 77/77

These tubes have steel support rods and top

It is probably a Mullard

5 record cleaner and am playing it on my Rega Planar 1 as I write

These 11 RCA gray glass 6D6 tubes were tested on our Paul Hart-calibrated TV7/U for shorts

General Electric GE 12AT7 ECC81 6679 Vacuum Tube Premium NOS NIB Hot-Stamped Bases Tube One measured 73/74 whileThis new old stock, new in box industrial grade GE 6679 12AT7 dual triode was tested on my Hickok 600A for shorts, gas and transconductance. There were no shorts or gas. Transconductance measured 4100 3400 micromhos. (New 6679s typically test within 1. 5 standard deviation of 4000 micromhos; minimum (65%) is 2600). It has gray, wing plates; a top, slant D getter and excellent flashing. I am playing them in my Bottlehead Crack headphone amplifier as I