Hello ecclectique,
I am so fascinated by your kindness, experience and knowledge that I have waited until this hour (02.14 over here) for your reply. THANKS!
YES, you are right, I meant the 7027A. My RCAs and Westinghouses did a great job in my Heathkits. I also have a pair of new Sovtek 5881s. They do sound much inferior to the metal base 7027A's in the Syrah, but maybe it is just because they still are brand new. Anyway, I will try my burnt-in RCA 7027A's in the Syrah (I hope Mick isn't reading this ;-))
The tube seller is the most reputed and most expensive in Germany, thank god the previous owner paid him for these tubes, not me. If you would like to know who he is, just out of curiosity, you can email me privately and I will gladly give you his site address. This practice of wiping the branding off is very old, he has been doing it for many years. He then writes his name and the tube type in different colours depending on the quality of the tube according to his measuring, testing, matching etc.
A huge thanks for the rectifier tip, a Hytron GZ-34 is on its way here and hope it will reach me before Xmas. I know I need the metal base GZ-34, but before I spend what is big money for me for the metal base Mullard or Philips, I thought I should try the Hytron, see if the problem vanishes. No, I did not and cannot measure the Mullard GZ-37, I really hope that the rectifier tube is the problem.
Thanks for your kind words on my system, your systems are truly extraordinary (I have heard the TW once in a show twelve or more years ago, WOW!). My Quads have PK (absolutely great guy) treble panels, new EHT blocks and protection clamps. New PK bass panels maybe next fall. The Radford STA-25 MkIII is a really good match, indeed. Before the Syrah I used a (Bruce Moore designed) Precision Fidelity C-7a sp (with step-up trannies for MC inside). Not at all bad, not at all, but the Syrah is in a different league. Now if the problem could go before Xmas so that I can enjoy my LPs for more than a few minutes!
Many thanks and regards, ecclectique!
Best,
frankiealverti