Mullard Blackburn ecc33 / 6SN7 GT NOS Pair Valvo / German Government markings RARE! REDUCED! [Expired]

Here are a beautifully matched NOS pair of some of the best sounding tubes ever made - Mullard Blackburn ecc33.  This is an excellent sub for 6SN7 type tubes, providing slightly more gain for a wonderfully dynamic hifi sound.   These examples were built for the German government in the 1960's and are branded Valvo.  Identical date codes.  Both tubes were tested on my MaxiPreamp 2 digital tester with well matched and balanced results - see pictures for test values.  NOS 6SN7 typically test between 1800 and 2200 uMhos on this tester, so these are incredibly strong and healthy.  These tubes were also checked for noise; all sections test below -82dBV.    Please contact me with any questions! Best, Mika