Matched Pair Sylvania 7C5 Vacuum Tubes Valves Gray Glass 5726 T14 Transconductance measured 50/52 for Tube

Transconductance measured 50/52 for Tube One and 53/52 for Tube Two where minimum (65%) is 25/25 and 100% is 39/39

new in box RCA 8056 Nuvistor tube tested to spec on our Paul Hart-calibrated TV7/U

new in box RCA triple mica 9002 tube tested to spec on our Paul Hart-calibrated TV7/U

but the bottle is firmly-cemented to it and there is no movement at all possible

This black plate GE 5Y3GT rectifier tube was tested on our Paul Hart-calibrated TV7/U for shorts

Matched Pair Sylvania 7C5 Vacuum Tubes Valves Gray Glass 5726 T14 Transconductance measured 50/52 for TubeThis matched pair of Sylvania gray glass 7C5 tubes was tested on our Maxi Matcher 2 with 400 volts on the plates and a bias of 36 volt for shorts, gas and transconductance. There were no shorts or gas. Transconductance measured 2340 micromhos with a plate current draw of 24. 5 milliamps for Tube One and 2070 25. 2 for Tube Two. (New US made 7C5s typically test with plate current from the mid teens to mid 30s with transconductance from 2300 micromhos