Matched Pair CBS Hytron 12SN7 12SN7GT Vacuum Tubes Black T Plates Tung-Sol NOS NIB Both tubes have thin cracks

Both tubes have thin cracks in their bases

Not for use in guitar and bass amps

steel support rods

These new old stock

They measured 50

Matched Pair CBS Hytron 12SN7 12SN7GT Vacuum Tubes Black T Plates Tung-Sol NOS NIB Both tubes have thin cracksThis matched pair of CBS Hytron 12SN7GT dual triodes was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. Transconductance measured 75 70 for Tube One and 77 72 for Tube Two where minimum (65%) is 50 50 and 100% is 77 77. They have black T plates; D getters; steel support rods; excised chevrons in their top mica spacers as well as 210 5439 and 5413 provenance date codes, respectively. I have