Matched Pair National Union NU 6J7 6J7GT Vacuum Tubes Valves Glass Bottles Tung-Sol Gebraucht copiously-illustrated book is in excellent

copiously-illustrated book is in excellent condition

new in box milspec RCA JAN-CRC-12SW7 tubes tested to spec on our Paul Hart-calibrated TV7/U

each with three rectangular holes

Transconductance measured 22 where minimum (65%) is 15

new in box matched pair of RCA steel plate 6AK5 tubes was tested on our Paul Hart-calibrated TV7/U tester for shorts

Matched Pair National Union NU 6J7 6J7GT Vacuum Tubes Valves Glass Bottles Tung-Sol Gebraucht copiously-illustrated book is in excellentThis matched pair of National Union glass bottle 6J7GT tubes was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. Tube One measured 42 while Tube Two measured 42 as well where minimum (65%) is 31. I have played them in my Musical Paradise 301 MK 3 with adapters (not included) as 6SJ7 substitutes and they sound excellent airy with excellent dynamics and signal bandwidth. They are a tad