Matched Pair RCA 6BL7 6BL7GTA Vacuum Tubes NOS-Testing February 10 2023 (New US-made 7408s typically test

(New US-made 7408s typically test with plate current from the mid-teens to mid-30s with transconductance from 2300 micromhos or so

These tubes have copper support rods

new in box GE 33GY7A tubes tested to spec on our Paul Hart-calibrated TV7/U

an O-getter

It is probably a Mullard

Matched Pair RCA 6BL7 6BL7GTA Vacuum Tubes NOS-Testing February 10 2023 (New US-made 7408s typically testThis new old stock testing matched pair of RCA 6BL7GTA dual triodes was tested on our TV7 U for shorts, gas and transconductance. There were no shorts or gas. Tube One measured 50 50 while Tube Two measured 49 54 where minimum (65%) is 25 25 and 100% is 38. 5 38. 5. These tubes have steel support rods; short bases; beefy black plates: side O getters; anode coolers for cooler operation and longer life. Both have BW date codes. I played them in my Alan