Matched Pair RCA-Cunningham 6K7 Vacuum Tubes Engraved Bottles NOS-Testing

Matched Pair RCA-Cunningham 6K7 Vacuum Tubes Engraved Bottles NOS-TestingThis new old stock testing, perfectly matched pair of RCA Cunningham 6K7 tubes were tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. Both measured 54 were minimum (65%) is 36 and 100% is 55. These tubes have engraved bottles. WE HAVE SCORES OF THOUSANDS OF VACUUM TUBES. IF IT'S NOT LISTED, WE MAY HAVE IT. PLEASE ALSO SEE OUT ETSY SISTER SITE "LOWTECHTWOO" AND OR CALL OR TEXT US AT 202 372 6931

new old stock brands are boxed by a contractor

It has the occasional pop and tick

I am playing it in my Pro-Ject Tube Box S phono preamplifier with an Ortofon X5-MC high output moving coil cartridge as I write and it absolutely silent

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

There were no shorts or gas and both measured 33 where minimum (65%) is 25

Transconductance measured 44 and 48 where minimum (65%) is 35

Micanol bases

45/47 and 52/48 where minimum on the TV 7 (65%) is 38/38

71                                                                                                Sylvania 01A Credit: $10

Tube One measured 62/72 while Tube Two measured 70/63 where minimum (65%) is 50/50 and 100% is 77/77

It measured 56/49 where minimum (65%) is 40/40 and 100% is 62/62

This lot of thirteen US-made 7F7 tested poorly and/or unevenly on our Paul Hart-calibrated TV7/U