RCA Black Plate 12BZ7 Vacuum Tube NOS NIB For Your Univalve Or Bottlehead In Honolulu 46 and 52 where minimum

46 and 52 where minimum (65%) is 35

They tested 51/52

Transconductance readings are 15

These three US-made

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

RCA Black Plate 12BZ7 Vacuum Tube NOS NIB For Your Univalve Or Bottlehead In Honolulu 46 and 52 where minimumThis 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