ECC83 - 12AX7

Equivalent 6L13, B339, 5751, 7729, E83CC
Near equivalent  
With different Vf  
CV number CV492, CV2011, CV4017, CV8156, CV8222, CV8312, CV10319
Swedish Mil.nr. M2462-438, M2462-465
Tektronix part no 154-0043-00
154-0094-00
Hewlett-Packard part no. 1932-0030