SUPER rare, among the earliest of Mullards with date codes (both apparently from 1957, 1956 being the first year ever for the date coded Mullards), taken from a small extension amplifier made in 1957/58, with these two original tubes in it! Beings that the unit was hi-fi and they were only used to power a small speaker, they weren't used hard at all. I probably don't have to tell you how rare and how amazing these tubes are. I only wish there were more! But they're arguably the best ever made! Guitarists and hi-fi freaks alike, both go crazy for these classic tone monsters (myself included!).  This is actually more than a fair price for these, as they can even go higher. 

The condition on both are excellent, with no signs of heavy use, the silk screened graphics are in nice shape with no discolor from use or high temperature. The only wear on the preamp tube shown here is from the tight fitting tube cover/sleeve, that was grounded and used to block out RF and other interference. If it weren't for the tight fitting cover, I would imagine it would be a very minty graphic. As it is, it's still extremely rare to see one this clean and in tact from this early on.

This auction is for the single 12AX7. Neither of the tubes were hit very hard and have plenty of life left in them. They both sounded stellar in the amp and fresh, with no odd sounds, static, rattling or anything objectionable to be heard. This is a no reserve auction for one of these extremely rare tubes so good luck and ask me any questions you may have. I had these tested by a friend and they both tested as "good". Thanks for looking!