Matched Pair Sylvania 6K6 6K6GT Vacuum Tubes Valves Angel Records 35657 The two on the left

The two on the left were made by Mullard

new in box GE 25C5 tube tested to spec on our Paul Hart-calibrated TV7/U

I am writing during the first few pianissimo minutes and the surface noise is distracting

new in box milspec National Union JAN-CNU 2X2A VT-119 879 tube tested to spec on our Paul Hart-calibrated TV7/U

Matched Pair Sylvania 6K6 6K6GT Vacuum Tubes Valves Angel Records 35657 The two on the leftThis matched pair of Sylvania MANUFACTURED, Philco LABELED 6K6GT tubes was tested on our Maxi Matcher 400 volts on the plates and a bias of 36 volts for shorts, gas and transconductance. There were no shorts or gas. Tube One drew 18. 4 milliamps' plate current and measured 1460 micromhos. Tube Two measured 19. 5 1710. New nominal is within one standard deviation of 1900. These tubes have copper support rods; rectangular mica spacers; anode radiators