RCA Black Plate 12BZ7 Vacuum Tube NOS NIB For Your Univalve Or Bottlehead In Honolulu Tube One measured 62/72 while

Tube One measured 62/72 while Tube Two measured 70/63 where minimum (65%) is 50/50 and 100% is 77/77

This matched pair of Sylvania black plate 6CL6 tubes was tested on our Paul Hart-calibrated TV7/U for shorts

This lot of three Super Silvertone 6K7G tubes were tested on our Paul Hart-calibrated TV7/U for shorts gas and transconductance

This matched pair of RCA steel plate 6AK5 tubes was tested on our Paul Hart-calibrated TV7/U tester for shorts

RCA Black Plate 12BZ7 Vacuum Tube NOS NIB For Your Univalve Or Bottlehead In Honolulu Tube One measured 62/72 whileThis new old stock, new in box RCA 12BZ7 tube tested to spec on our TV7 U. It measured 26 28 where minimum (65%) is 18 18 and 100% is 28 28. It has black plates; an O getter; steel support rods and outstanding flashing. I have listened to it in my Bottlehead Crack headphone amplifier and it sounded great. It is listed only as a good substitute for the 12AX7 which is only a fair substitute for the 12AU7 the recommended preamp tube for this headphone