RCA Radiotron Number / Type 56 Vacuum Tube Globe Balloon Style Engraved / Stamped Base NOS-Testing

RCA Radiotron Number / Type 56 Vacuum Tube Globe Balloon Style Engraved / Stamped Base NOS-TestingThis new old stock TESTING RCA Radiotron type 56 triode was tested on our Paul Hart calibrated TV7 for shorts, gas and transconductance. There were no shorts or gas. It measured an outstanding 82 where minimum (65%) is 37 and 100% is 57. It has a thin, rounded rectangle top mica spacer; rounded dark gray plates; a dimple, sheet getter; excellent flashing and a sharply engraved base. WE HAVE SCORES OF THOUSANDS OF VACUUM TUBES. IF IT'S NOT LISTED, WE

The shield walls are very thick and do not appear to be made of lead -- perhaps a lead or bismuth alloy

and dynamics even though these amplifiers use 6J5s

Tube One: 72/78

new in box RCA 17JM6A tubes tested to spec on our Paul Hart-calibrated TV7/U

Their readings are 44

It was manufactured in the Soviet Union as it has 74-36 date codes

5 inches in circumference

Tube Two: 21

12AT7s are notorious for their unmatched triodes and their deviation from nominal parameters

This lot of three new old stock-testing 1S2A / DY87 tubes werw tested 68 on our Paul Hart-calibrated TV7/U for shorts

Tube Five: 25

There is no transconductance reference reading and as I test new in box 12AU7s