Whistling piston valves

[Sousa_Jack]

I recently ran into a problem with my BMB J765LQ tuba where the 1st and 2nd valves are whistling whenever I press them down. Thoughts on this?

[arpthark]

It really depends on whether or not they can carry a tune.

[marccromme]

Yes. Check your ventilation holes in the bottom caps , and stem hole in top caps. If they have sharp rims or edges, it might help rounding them a bit. Air is pressed through them when moving the pistons, and since these holes are relatively small compared to the diameter of the pistons, air speed there is high, resulting in whisteling over their edges.

Smuthing edges round will help, eventually drilling them a tiny bit larger too.Best done in a turning lathe, so ask your repair man to do it.

And make sure that the ventilation holes in the pistons are not clogged either. ..