RCA Black Plate 6L6 6L6GC Vacuum Tube For Your Univalve Larry Ferrari Transconductance measured micromhos with a

Transconductance measured micromhos with a plate current draw of milliamps

it is probably plated

Two are GE and two are Sylvania

new in box Raytheon 35Y4 tube tested to spec on our Paul Hart-calibrated TV7/U

This happens perhaps once -- maybe twice -- per decade

RCA Black Plate 6L6 6L6GC Vacuum Tube For Your Univalve Larry Ferrari Transconductance measured micromhos with aThis RCA 6L6GC output tube was tested on our Maxi Matcher with 400 volts on the plates and a bias of 48 volts for shorts, gas and transconductance. There were no shorts or gas. Transconductance measured 1320 micromhos and it drew 63 milliamps' plate current. (New US made 6L6s typically test with plate current from the low 20s to mid 30s with transconductance from 2200 micromhos or so.) This tube tested above spec for plate current draw and below spec