RCA Cunningham 5Z3 Vacuum Tube Black Plate Rectifier Shoulder ST Shape 3CZ3A Octal new in box Sylvania 1291

new in box Sylvania 1291 industrial-quality tubes tested to spec on our Paul Hart-calibrated TV7/U

I am playing it in Bottlehead Crack headphone amplifier as a 12AU7 substitute and it sounds excellent

This GE 35Z5GT tube tested 55 our Paul Hart-calibrated TV7/U where minimum (65%) is 40 and 100% is 62

This matched trio of GE 12HG7 tubes was tested on our Paul Hart-calibrated TV7/U (on the 12BY7 setting) for shorts

RCA Cunningham 5Z3 Vacuum Tube Black Plate Rectifier Shoulder ST Shape 3CZ3A Octal new in box Sylvania 1291This RCA Cunningham 5Z3 rectifier tube was tested on our Paul Hart calibrated TV7 U for shorts, gas and emissions. It tested 68 in Section One and 58 in Section Two where minimum (65%) is 40 40 and 100% is 62 62. It has a tall, engraved stamped base; black plates, copious amounts of flashing and a nice, old fashioned shoulder bottle. WE HAVE SCORES OF THOUSANDS OF VACUUM TUBES. IF IT'S NOT LISTED, WE MAY HAVE IT. PLEASE ALSO SEE OUT ETSY SISTER SITE