John Packer Valves

[BessonRocks]

I have a JP-374ST and use mead light springs. After cleaning my instrument I have found that the springs vibrate while playing. The diameter of the spring is too small and is not seating but sitting on top. I've tried putting tuba springs in but they are too big. What size springs are in this instrument?

[ChristianeSparkle]

Have you unscrew your vales, take it halfway out of the valve and put it back in? That's to try and re-seat the springs. Mead springs will not sit as nicely on the JP line since Mead springs are tapered while the bottom of the JP has a raised part in the middle. But if seated properly, it shouldn't vibrate. I personally used Mead light springs on my JP274 without much issues. I've experienced said vibration before and re-seating the springs properly fixed it for me

[BessonRocks]

Hi! I'll try to unscrew them halfway and place them back in. Do you happen to know what size springs the jp uses?

[RickF]

See Dave Werden's helpful video tip on reseating a noisy valve spring:

https://www.youtube.com/watch?v=XlVYigd52-o

[leisesturm]

I'm pretty sure that there isn't too much variation (any?) between brands of Euphonium springs with respect to their overall diameter. They are, for all practical purposes, interchangeable. Tuba springs (as you found out) cannot be used in Euphoniums. But between different Tuba models, most anything sold as a 'Tuba Spring' is going to work. That said, I have found that since the JP line is 'bottom sprung', if the spring vibrates, unscrewing the bottom cap several turns and/or taking the bottom cap off completely and re-seating the spring before tightening it again will almost always cure buzzing. But the sure fire fix (that I haven't tried) is plastic coated valve springs (Yamaha?).