7 Twist-Lock J-Slot Spring-Loaded #139 Tube Shields For 12AX7-Size Vacuum Tubes Lot Of Seven

7 Twist-Lock J-Slot Spring-Loaded #139 Tube Shields For 12AX7-Size Vacuum Tubes Lot Of SevenThis lot of seven of J slot, spring loaded, 12AX7 size tube shields is in excellent shape. They are all the same size, though some are stamped "138" and others are not. MOST FORMS OF SHIPPING EXCEPT MEDIA MAIL ARE AUTOMATICALLY INSURED UP TO $100. ETSY PURCHASE PROTECTION COVERS ITEMS UP TO $250 IN VALUE. IF AN ITEM IS MARKED "DELIVERED," AND YOU HAVE NOT ACTUALLY RECEIVED IT, THE FIRST STEP IS FOR YOU TO CONSULT YOUR MAIL CARRIER TO GET THE EXACT

This new old stock-testing Svetlana 6550B / 6P27 perforated plate output tube was tested on our Maxi-Matcher 2 with 400 volts on the plates and a bias of -48 volts for shorts

There were no shorts and it measured a perfectly-balanced 44/44 where minimum (65%) is 34/32 and 100% is 52/52

There were some pops and ticks

5 out of nine

I am listening as I write and this album sounds very good with only an occasional click and pop

8 milliamps' plate current and measured 1600 micromhos

It measured 42 in its triode section where minimum (65%) is 25 and 100% is 39

DB and CV batch codes

This new old stock-testing matched pair of RCA 6CG7 / 6FQ7 dual triodes was tested on our Paul Hart-calibrated TV7/U for shorts

(New US-made 6L6s typically test with plate current from the low 20s to mid 30s with transconductance from 2200 micromhos or so

new in box RCA 6HV5A tubes tested to spec on our Paul Hart-calibrated TV7/U

I am playing it it in my Bottlehead Crack headphone amplifier as I write and it sounds great