Baldwin Select Sylvania 12AU7 12AU7A ECC83 Vacuum Tube Valve With An Introduction It has outstanding silkscreening

It has outstanding silkscreening

I am playing them as I write in on of my Sound Craftsmen RC-2 monoblock amplifiers with RCA Living Stereo's CD of Bartok's "Concerto For Orchestra

new in box GE 6BK4 / 6EL4 tubes tested to spec on our Paul Hart-calibrated TV7/U

They have NU 188-5 and 3-09 188-5 date/provenance codes

a balloon / globe bottle

Baldwin Select Sylvania 12AU7 12AU7A ECC83 Vacuum Tube Valve With An Introduction It has outstanding silkscreeningThis Sylvania MANUFACTURED, Baldwin BRANDED and SELECTED 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 an almost perfectly balanced 82 84 where minimum (65%) is 56 56 and 100% is 86 86. This tube has narrow, gray, 16 MM plates; excellent flashing; a top, O getter; copper support rods; excellent silkscreening and 312 132 provenance date