RCA 6680 12AU7 12AU7A ECC82 Vacuum Tube Valve Industrial Version NOS-Testing Perfect For Univalve And Bottlehead Number Engraved Tube Three (diodes): 79/40

Tube Three (diodes): 79/40

Sylvania-BRANDED 8BQ5 tube tested to spec on our Paul Hart-calibrated TV7/U

53/53 where minimum (65%) is 40/40 and 100% is 62/62

This book is in good condition

It comes with a box

RCA 6680 12AU7 12AU7A ECC82 Vacuum Tube Valve Industrial Version NOS-Testing Perfect For Univalve And Bottlehead Number Engraved Tube Three (diodes): 79/40This new old stock testing RCA 6680 12AU7A ECC82 dual triode was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. Transconductance measured a nicely balanced 92 95 where minimum (65%) is 56 56 and 100% is 87 87. The 6680 is the industrial version of the 12AU7A. It has gray 12MM plates; excellent flashing for an extremely hard vacuum and extended tube life and a top O getter. I have played it