4 Tung-Sol 6K6 6K6GT Vacuum Tubes Black Glass Lot Of Four NOS-Testing 25BK5 though is not recommended for

though is not recommended for this headphone amp which was designed for 12AU7s

Transconductance measured 41/49 for Tube One and 44/44 for Tube Two where minimum (65%) is 32/32 and 100% is 49/49

(New US-made 6V6s typically test with plate current from the mid teens to mid 30s with transconductance from 1700 micromhos or so

I played this tube this morning it in my Bottlehead Crack headphone amp with Sennheiser SD 580s and it sounded excellent

It measured 70 where minimum (65%) is 46

4 Tung-Sol 6K6 6K6GT Vacuum Tubes Black Glass Lot Of Four NOS-Testing 25BK5 though is not recommended forThis new old stock testing lot of six Tung Sol black glass 6K6GT tubes were tested on our Maxi Matcher 2 with 325 volts on the plates and a bias of 36 volts for shorts, gas, plate current and transconductance. There were no shorts or gas and they measured as follows (from left to right, top to bottom): Tube One: 31. 8 milliamps' plate current 2170 micromhos; Tube Two: 35. 1 1980; Tube Three: 40 2120 and Tube Four: 42. 1 2260. New nominal