Thank you tubenet knowledge base - issue solved!

[Wilco]

I bought a Melton 200 recently and had not played it much. A week ago I discovered that the C above tuning Bb was really hard to center. Allmost impossible at pp, doable at Forte. I started searching the archive for clues.

First clue was to look for the node the C resonates at. The tip I read was about opening the spitvalve... And voila! The C was allmost exactly the same as with the spitvalve open.

Second clue was a case about a burr at the inside where the spitvalve is. In that case it solved a problem note. I checked the instrument and there was quite a burr there. I carefully sanded the inside with sandpaper mounted on a screedriver.

This did the trick! Very happy about it!