They have only had a maximum of 40 hours of use, so have miles to go!
The difference in sound, when compared to other tubes, is, in simple words; the comparison of a Grand Piano (Mullard) and a Standard Piano (Other Tubes). I bought them as NOS a few years back and used them on my Brunetti amp only a few times; for for less than 40 hours. I now have no use for them, hence the sale. They sound utterly amazing.
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