Groove Tube 12AX7 / ECC83 / GT-ECC83-S Premium Vacuum Tube For Your Univalve December 18 2020 They were made by Ken-Rad

They were made by Ken-Rad although one is branded "Crosley

34 and 35 where minimum (65%) is 25

These four US-made 6SF7 tubes were tested on our Paul Hart-calibrated TV7/U for shorts

rounded rectangle

Groove Tube 12AX7 / ECC83 / GT-ECC83-S Premium Vacuum Tube For Your Univalve December 18 2020 They were made by Ken-RadThis Groove Tube GT ECC83 S ECC83 12AX7 dual triode was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas and it measured 40 37 where minimum (65%) is 32 32 and 100% is 49 49. It has outstanding silkscreening; excellent flashing and an O getter. I am playing it in one of my ArtSound monoblocks as I write and it is absolutely silent. WE HAVE SCORES OF THOUSANDS OF VACUUM TUBES. IF IT'S NOT