Shuguang 12AX7 Pavane/Psvane Reference.

I was wonder if anyone has feedback about these tubes. They have a very good review at Positive Feedback.

I'm searching for good tubes to replace the "no brand" 12AX7 tubes that came in my preamplifier. Sadly the "perfect" tubes (50's NOS Mullards or Telefunkens) can cost almost the same that what my preamp cost. Also, I have heard about overpriced old tubes that doesn't produce good sound, simply because they are poorly matched. With the Groove Tubes Mullar replicas out of the market few years ago, I really don't know what should be my next tube investment.

Thanks for reading!.