I have not re tubed the Jolida, but if you list the tubes that it uses, what came from the factory (the brand) and what you like and dislike about the sound, I will give you suggestions that may allow you to tailor the sound more to your liking. If you are just re tubing to replace bad or worn tubes, and you have no objections to your systems sound, the easy path is to replace with like type and brand as what it was provided with.
