They retain a fine sense of "air" at the top, and the upper midrange is smooth and liquid. These tubes reproduce the human voice, especially female voices, with haunting realism. The Mitcham Mullard tubes are also known to have an attractive sparkle at the top with rich bass... Now we know where that "warm British jacket" comes from!
We treasure this pair also because of the pristine cosmetic condition - 100% of the paint is intact and the identical Blackburn factory date code is perfectly visible on both tubes. B5G2 (B = Blackburn, 5 = 1965, G = September, 2 = 2nd week of the month). The tube tested Strong NOS (110%+ GM) on a Mercury 2000 tube tester with the following result mutual conductance in.
Good tubes start at 7000 and new tubes incl. NOS/NIB 12,500 - 13,000, and the Mercury 2000's rated mutual conductance (nominal) for new tubes is 12,500. Test result can also be seen in the pictures. In case you wonder what all these numbers mean to your sound experience, it's actually quite straightforward: mutual conductance directly translates to a tube's ability to amplify sound , so the higher the numbers the stronger. The original military box (no Mullard logo - used for internal distribution) will be included for this tube.
Soundlumia does not encourage or participate in such practice. Nor will we respond to any messages inquiring about this topic. Soundlumia sets extremely high quality standard for the products we deliver. Sound experience is a very subjective thing, and let's be real it's not that easy to run into compatibility issues between amps and tubes so that one won't fly, either.
Secondly, if you are a tube roller looking to game the return system, Number One STOP. We have seen it all and we know what you're up to.