Matched Pair National Union NU Number / Type 76 #76 Vacuum Tubes Valves

Matched Pair National Union NU Number / Type 76 #76 Vacuum Tubes ValvesThis matched pair of National Union type 76 triodes was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. Transconductance measured 49 for Tube One and 52 for Tube Two where minimum (65%) is 36 and 100% is 55. These tubes have shiny, dark gray, rounded plates; crenelated, top, rectangular mica and smooth rectangular bottom spacers and excellent flashing. I have played them in my Radio Craftsmen

It is dead quiet when the preamp is muted and has excellent frequency response

but I would step it up to an 8 or so as this sound striping recording is truly cutting edge

new in box matched pair of GE 6FQ7 / 6CG7 dual triodes was tested on our Paul Hart-calibrated TV7/U for shorts

new in box RCA 6W4 / 6W4GT tubes tested to spec on our Paul Hart-calibrated TV7/U

Etsy will indicate how many tubes are available in this Dutch auction

This matched pair of RCA black plate 6K6GT tubes was tested on our Maxi-Matcher tube tester with 325 volts on the plates and a bias of -36 volts

new in box GE 6AS8 tubes tested to spec on our Paul Hart-calibrated TV7/U

new in box Philco 25Z5 tubes tested to spec on our Paul Hart-calibrated TV7/U

I just cleaned this double album on my VPI 16

One is milspec

new in box Sylvania 7A6 tubes tested to spec on our Paul Hart-calibrated TV7/U

double-D getter and a 337 2R48 date / provenance code