Have just gone through another power tube meltdown in my ST120, and lost the GZ34 along with it. Have a Weber WZ68 for backup, however I like the look of glowing tubes. In the past I have used Sovtek, J/J, and Ruby rectifiers. At present I have just installed my last J/J. I had two for backup, put one in with the new power tube duo and it promptly went up in a flash in just over 24 seconds. Rechecked one channel at a time with another GZ34 and found no problems with either side separately, and then both together with no problem. You just can't tell if you have a weak tube even when new.
Need to purchase some backup GZ34's (Again), and was interested in your thoughts regarding your experiences with the different manufacturers.