OP... CEI was a distributor that sold quality tubes made by other manufacturers.
Zaerix relabeled other manufacturers' tubes. I found a couple in used components.
https://www.18watt.com/viewtopic.php?t=23510
Buying tubes for $20 without etched factory codes or test results is a shot in the dark. Even if it sounds good, it may not last long. And with rebadged tubes and no description, you won't know their sonic signature.
My advice, spend some money and buy from a reputable dealer who posts tube measurements and offers exchanges. There are many good NOS tubes for $50.
Zaerix relabeled other manufacturers' tubes. I found a couple in used components.
https://www.18watt.com/viewtopic.php?t=23510
Buying tubes for $20 without etched factory codes or test results is a shot in the dark. Even if it sounds good, it may not last long. And with rebadged tubes and no description, you won't know their sonic signature.
My advice, spend some money and buy from a reputable dealer who posts tube measurements and offers exchanges. There are many good NOS tubes for $50.