Sylvania 12AU7 ECC83 Early Production Black Plate Copper Support Rods Vacuum Tube For Your Bottlehead Berman Plays Liszt This new old stock-testing RCA

This new old stock-testing RCA 12BH7A was tested on our Maxi Preamp II for shorts

top chamfered solid-O getters and two additional vertical support rods for increased rigidity and lowered microphonics

round mica spacers

They have 4-39 188-5 and 3-43 188-5 date codes/EIA code

It measured 80 where minimum (65%) is 50 and 100% is 77

Sylvania 12AU7 ECC83 Early Production Black Plate Copper Support Rods Vacuum Tube For Your Bottlehead Berman Plays Liszt This new old stock-testing RCAThis Sylvania 12AU7 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 68 72 where minimum (65%) is 56 56 and 100% is 86 86. This tube has black, slightly shiny ladder plates; excellent flashing; a top, slanted D getter; copper support rods. This is an early production 12AU7. It is not a 12AU7A WE HAVE SCORES OF THOUSANDS OF