Matched Pair General Electric GE 6BL7 6BL7GTA Vacuum Tubes NOS NIB

Matched Pair General Electric GE 6BL7 6BL7GTA Vacuum Tubes NOS NIBThis new old stock, new in box (For Tube One) matched pair of GE MANUFACTURED 6BL7GTA dual triodes was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. Transconductance measured 49 50 for Tube One and 50 50 for Tube Two (RCA LABELED). where minimum (65%) is 25 25 and 100% is 38. 5 38. 5. They have O getters; copper support rods; great flashing; stout black plates; anode radiators for cooler

This lot of four Sylvania 12BF6 tubes tested to spec on our Paul Hart-calibrated TV7/U

These tubes have top and side black / dark-gray bottles

Their internal structures are all the same

Transconductance readings are 46

5 record cleaner and then played it on my Rega Planar Threes

and their top mica spacers have two X patterns incised into them

I do not recommend them for applications with vibration

I am playing them as I write in my Alan Eaton single-ended 45 amplifier with RCA Living Stereo's CD of Bartok's "Concerto For Orchestra

These two US-made 14A4 tubes tested to spec on our Paul Hart-calibrated TV-7/U

This milspec CBS-Hytron USN-CHY-5Y3WGTA / 5Y3 black plate rectifier tube was tested on our Paul Hart-calibrated TV7/U for shorts

There were no shorts or gas and they measured as follows (from left to right

Tube One measured 95%/93% and 95%/94% for Tube Two