I would try the German TAD 12AU7 tubes. I replaced the Electro Harmonix with the TAD's and it was quite nice. They are not NOS tubes, but it was an improvement.
It depends. If you like a warmer, sweeter sound; go with something from Britain(Mullard/Brimar). If more detail and transparency is your cup of tea; something from Germany(Telefunken/Siemens). Amperex offerings will get you somewhere between those two. Just don't skimp on your purchase, or you'll rob yourself of much musical enjoyment.
Thanks guys, I also have a Rogue Cronus Magnum , it came with Sylvania & I have Siemens in it now - different presentations but I like it with either. Will experiement per normal.
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