Matched Pair RCA 6F6 6F6G Vacuum Tubes ST Shoulder Shape T33 for Backup It measured 35/34 where minimum

It measured 35/34 where minimum (65%) is 40/40 and 100% is 62/62

These US-made 12SF7 tubes were tested on our Paul Hart-calibrated TV7 for shorts

TV7/U readings are in (parenthesis)

round mica spacers and anode radiators for cooler tube operation and longer life

Most don't test great

Matched Pair RCA 6F6 6F6G Vacuum Tubes ST Shoulder Shape T33 for Backup It measured 35/34 where minimumThis matched pair of RCA MANUFACTURED 6F6G tubes was tested on our Maxi Matcher 325 volts on the plates and a bias of 36 volts for shorts, gas and transconductance. There were no shorts or gas. Tube One (Emerson LABELED, RCA MANUFACTURED) drew 16. 6 milliamps' plate current and measured 1800 micromhos while Tube Two measured 17. 6 1780 where new 6F6s measure from approximately 2000 micromhos with plate current draw in the 20s. These tubes have 274 649