I ordered a cheap old tube off ebay, it was delivered today so I swapped it over and I have music again
so there must have been something wrong with the tube.
The I ordered a brimar 12au7, but I got a tube that has the brand ZaeuX on it, the guy also gave me a second tube as a free gift which is just labeled 12AU7A, with no other branding.
With the Zaeux tube, there is a little more treble, and you notice listening to a track with a busy drum section, the drums seem to have a bit more texture.
The non branded tube was a bit smoother sounding, but sounded a bit cleaner.
It would be good to know if it sounds better or worse than the original; I seem to remember the original sounding better, but that could have been the glass of single malt I had
Where should I go from here do you think, I am wondering will I get much more detailed sound etc spending a bit more?
Thanks everyone for your help while this was fixed it was reassuring to know that there were people willing to take the time to help me get to the bottom of it