Here is a lovely matched quad of 1958 Sylvania 12AU7A tubes that appear to be NOS. All 4 tubes have gray box plates, 2 micas, copper rods, and rectangular D getters. Green logos are complete with matching 58 00 29 date codes.
Tubes test 85/85, 87/85, 85/86, and 86/87, so you have a closely matched quad. Most new 12AU7s test between 85 and 90 on my Sencore tester, where 70 is the minimum ‘good’ reading. Tubes were negative for shorts and grid leakage, and passed the life test.
Asking price is $40 plus shipping. Payment is by PayPal.
