Who owns an amplifier that uses the 6C33 CB knows well the problems that this valve presents during the selection phase
From one sample to another, at the same anodic tension and grid applied, there can be differences in emission even 50%
With the vintage tube testers, but also with the current production models, it is impossible to detect the parameters in a reliable way as the anodic current can be attested even over 300 mA.
To perform a perfect matching we have therefore created a special tester.
I believe at the moment we are the only company in the world that can offer a real selection in multiples of this tube at a competitive price.
Each 6C33 CB ordered in the "matching version" will therefore be paired according to the desired quantity in copies, quartets, octets or further multiples
You can also specify in the notes, if you know, the values of anodic and grid that uses your amplifier in order to furter refine the selection.