I have 3 each of NOS 1963 SHIELD LOGO MULLARD Blackburn 12AX7 / ECC83 TUBES, Test as new (or better?).
I bought these last year on Agon as a matching and balanced set of 5. I only needed 2 and have these 3 remaining unused tubes available and need to free up some funds for other distractions.
I'm not a big tube expert, but do recognize the desirability and superior sound reputation of the Mullard Blackburn tubes. This seller provided these comments;
These are the best of the best period. No microphonics or noise. Tested for noise in a vacuum tube valley tube characterizer and live in a hifi amp. Personally hand picked from thousands of tubes for matching Mullard Blackburn dates and matched & balanced performance. The tubes have the codes etched 161 over B 3 A 1 indicating made in 1963, same month and week in Blackburn.
All three tested the same VTV 105/105. Individual tube tests and balance are 52/52, 49/51 and 51/48. Essentially perfectly matched and balanced.
$250 for the matched set of 3, includes standard shipping, insurance and ppal fees.

