Matched Pair General Electric GE 12SL7 12SL7GT Vacuum Tubes Valves NOS NIB Philharmonia new in box matched pair

new in box matched pair of Sylvania gray glass 7C5 tubse was tested on our Maxi-Matcher 2 with 400 volts on the plates and a bias of -36 volt for shorts

This Tung-Sol 6L6GC was tested on our Maxi Matcher 2 for shorts

but with some wear

Transconductance measured 24

100% is 77/77

Matched Pair General Electric GE 12SL7 12SL7GT Vacuum Tubes Valves NOS NIB Philharmonia new in box matched pairThis new old stock, new in box matched pair of GE MANUFACTURED 12SL7 12SL7GT dual triodes was tested on our Pau Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. Transconductance measured 38 41 for Tube One and 42 41 for Tube Two (RCA LABELED) where minimum (65%) is 32 32. These tubes have copious bottom flashing, bottom, D getters, steel plates and steel suppost rods. WE HAVE SCORES OF THOUSANDS OF VACUUM TUBES.