Speaking of Repairs/Adjustments: How About Valve Alignment?
by, 07-11-2007 at 06:00 PM (175 Views)
A previous post discussed re-working curved tubing to make it fit more "comfortably" as part of the whole horn. But with valved instruments, it is also important to make sure that the valve ports are perfectly aligned. When the valve is up or down, there are tunnels in the valve that should line up with the slides' entrance.
Some horns are not made carefully enough and the alignment is not good. The will affect response and intonation.
The most common problem is the vertical alignment. Usually this can be fixed by a good repair person easily. They take measurements and make sure to put felts of the correct thickness on the top of the valve piston and under the valve button. These two locations control the vertical "stops" of the valve travel.
Valves may also be misaligned horizontally. This can be caused by sloppy placement of the valve guide slot or the guide itself. Correcting this is more challenging but can be done be a good craftsman.
In the case of compensating horns the alignment is even more critical because there are so many more junctions. On a 4-valve compensating euphonium, the rear compensating slide on the first valve is usually removable. If you take it out, you can see readily if the ports are aligned with the valve up and down. If the first valve seems aligned, then look across the top buttons of all 3 valves and see if they are in a perfectly straight line. They should be.
As always, it is a good idea to know and use a talented repair technician.