Mullard ECC83 f91 long plate square getter 1957 NOS labeled Mazda pair- tested

Beautiful pair NOS Mullard ECC83, 1957 square getter same production dates f91 B7H and B7J. Tubes were tested on my recently calibrated AVO CT160 at. Tube 1 - 1.8 mA/2.4 mAV. 1.8 mA/2.4 mAV. Tube 2 - 1.4 mA/2.3 mAV.

1.3 mA/2.2 mAV. Where 1.2 mA/1.6 mAV is considered 100%. This is tube that came out as successor to MC1 tube with same internal structure and same sound.