This matched pair of Sylvania-made, National-branded 5693 12AU7 / ECC82 preamp tubes was tested on my Hickok 600A for shorts, gas, and transconductance. There were no shorts or gas. Transconductance was 2100/1900 micromhos for Tube One and 2100/1900 for Tube Two (new/nominal is 2200; minimum (60%) is 1320). These tubes are in the spring of their lives, so to speak, and have a very long life expectancy ahead. I played them in my Antique Sound Lab 805 mono blocks; they sounded fine and were dead quiet when the preamp is muted. They have uniformly-good flashing; O getters, and pretty decent silkscreening. IF YOU DO NOT SEE WHAT YOU NEED, PLEASE EITHER CALL ME AT 202-256-6336 OR EMAIL ME AT LOWTECHELEC@COMCAST.NET. ALSO I HAVE OTHER INTERESTING TUBES ON AUDIOGON UNDER THE SAME NAME I USE HERE. SHIPPING IS A FIXED CHARGE AS I DO NOT HAVE A STANDARD SUPPLY OF BOXES OR TIME TO FINE-TUNE SHIPPING CHARGES. IF THIS ITEM IS LOST AND YOU DID NOT ELECT TO INSURE IT, THE LOSS IS YOURS ALONE. TUBES ARE GUARANTEED GOOD ON SHIPMENT. IF YOU FEAR DAMAGE IN TRANSIT, PLEASE INSURE THEM! I CANNOT GUARANTEE FOR FAILURES AFTER POWER UP AS THERE IS NO WAY TO DETERMINE HOW TUBES WILL INTERACT WITH YOUR ELECTRONICS; NOR IS THERE A WAY TO DETERMINE WHETHER THEY MAY HAVE FATAL FLAWS! I CAN ONLY TEST FOR THE PARAMETERS MENTIONED ABOVE. ALL ITEMS UNPAID FOR AFTER 10 DAYS WILL BE AUTOMATICALLY RELISTED. A SIMILAR ITEM WILL BE SUBSTITUTED FOR PAYMENTS ARRIVING LATE IF THE RELISTED ITEM HAS SOLD.

Your bid is a legally binding contract to purchase the item from the seller, so only place a bid If you're serious about buying the item.