Re: Re: Re: Re: Vented valves


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Posted by Rick Denney on November 14, 2000 at 00:50:36:

In Reply to: Re: Re: Re: Vented valves posted by tubalew on November 13, 2000 at 17:52:27:

It's really very simple to describe. A piston will have a small vent hole in the portion of the valve body that covers the valve-tubing port when the valve is not depressed. No sound is going through that tubing, but the air in the tubing is vented out through the bottom of the valve. All you have to do is make a hole in the valve under that port (located by careful measurement). Of course, you have to know how to make a smooth hole in a cylindrical casing...

Rotary valves are vented with a small hole in the casing right between the valve tubing branches. This is the tubing that project back toward your right hand while playing. Many horns, including some Miraphones, have these holes cut at the factory.

In terms of how it affects playing, it does. For the better. My piston Yamaha 621F is ventilated, and it sound just as it did before the vents were cut. *But I never moved the slides on that horn except to empty water*.

On my Miraphone, I'm pushing that first valve slide in and out all the time, but you'll never hear any effects from that, because of the vent.

On the York, however, I have problems with popping and the like because I move the slide at times when the valve is not depressed, and build pressure or vacuum in the valve tubing. I am afraid to vent these valves, because of the potential for allowing a point of delamination on the piston's plating. It was never a problem with the Yamaha--the valves are solid Monel.

Venting those York valves would eliminate the extra percussion sounds accompanying my manipulations of the tuning slide.

Rick "snap, crackle, pop" Denney


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