Matched Pair General Electric GE 12SL7 12SL7GT Vacuum Tubes Valves NOS NIB Philharmonia new in box GE 1821A

new in box GE 1821A / Z-1879A is still sealed in its plastic baggie

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

This pressing has light surface noise audible in quiet passages and barely audible in voice-level passages

Transconductance measured 24

but with some wear

Matched Pair General Electric GE 12SL7 12SL7GT Vacuum Tubes Valves NOS NIB Philharmonia new in box GE 1821AThis 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.