National Union NU 6R7 6R7G Vacuum Tube Valve Shoulder Shape NOS NIB Casting Pearls

National Union NU 6R7 6R7G Vacuum Tube Valve Shoulder Shape NOS NIB Casting PearlsThis new old stock, new in box National Union 6R7 6R7G tube tested to spec on our Paul Hart calibrated TV7 U. 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 IF YOU DO NOT SEE WHAT YOU NEED OR HAVE ANY QUESTIONS. 1. MOST FORMS OF SHIPPING EXCEPT MEDIA MAIL ARE AUTOMATICALLY INSURED UP TO $100. ETSY PURCHASE PROTECTION COVERS ITEMS

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This tube has two additional vertical support rods

Transconductance measured 41/42 where minimum (65%) is 21

They tested as follows: 55

This matched pair of GE 12B4A tubes was tested on our Paul Hart-calibrated TV7/U for shorts

They measured 62 and 76 where minimum (65%) is 46 and 100% is 71

79/77 where minimum (65%) is 50/50

35 and 37 where minimum (65%) is 25

new in box Sylvania 6LU8 tube tested to spec on our Paul Hart-calibrated TV7/U

Probably Mullard

Tube One measured 60 while Tube Two measured 70 where minimum (65%) is 46 and 100% is 71

Plate Current Draw: 71