4 US-Made 6SF7 Vacuum Tubes Valves Lot Of Four GM Delco Zenith These tubes have excellent silkscreening

These tubes have excellent silkscreening

perfectly-matched pair of RCA 6K7 tubes were tested on our Paul Hart-calibrated TV7/U for shorts

Both are acid-etched

O getter and an 805 ACP date / provenance code

4 US-Made 6SF7 Vacuum Tubes Valves Lot Of Four GM Delco Zenith These tubes have excellent silkscreeningThese four US made 6SF7 tubes were tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. They tested as follows: 40 32, 65 28, 74 37 and 76 54 where minimum (65%) is 50 40. Most don't test great, but most should work in most circuits. WE HAVE SCORES OF THOUSANDS OF VACUUM TUBES. IF IT'S NOT LISTED, WE MAY HAVE IT. PLEASE ALSO SEE OUT ETSY SISTER SITE "LOWTECHTWOO" AND OR CALL OR TEXT US AT 202 372