Sylvania 12AU7 12AU7A NOS-Testing Copper Support Rods Triple 3 Mica Vacuum Tube For Your Bottlehead Univalve

Sylvania 12AU7 12AU7A NOS-Testing Copper Support Rods Triple 3 Mica Vacuum Tube For Your Bottlehead UnivalveThis Sylvania triple mica 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 73 79 where new nominal is 50 50. This tube has two additional vertical support rods; an additional mica spacer for low microphonics; crenelated, round mica spacers and excellent flashing. I have played it in my Bottlehead Crack headphone amplifier and it sounds

59 60 and 64 where minimum (65%) is 40

This tube has a bottom D getter and an E9M date code which means it was likely made by Sylvania

I cleaned this album on my VPI 16

That song was a monster hit and defined an entire summer if my memory is correct

This new old stock-testing matched pair of milspec RCA 1619 tubes were tested on our Paul Hart-calibrated TV7/U for shorts

Tube One measured 62 while Tube Two measured 69

This NEC 4M-P12 tube tested to spec on our Paul Hart-calibrated TV7/U

It measured 60 where minimum (65%) is 37

This United 805 output triode was tested on our Paul Hart-calibrated TV7/U with 180 volts on the plates and a bias of 0 volts for shorts

new in box RCA 6W4GT tubes tested to spec on our TV7

These 11 RCA gray glass 6D6 tubes were tested on our Paul Hart-calibrated TV7/U for shorts

T-plate 12SN7GT dual triodes was tested on our Paul-Hart-calibrated TV7/U for shorts