Valve Travel
By John A. Tuttle
Hi All, I have only two things to say about valve travel and one suggestion. Anyone who has ever rebuilt a valve chest will testify to the fact that if the travel is over .040 inches, you can really hear the valves change state. It is annoying and severely detracts from otherwise enjoyable music. This is especially true of Dou-Art units because of the physical placement of the chest.
Secondly, Aeolian units with the plastic unit-block valves have an average clearance of .045 and they are very noisy. Tiss-tiss-tiss. I dislike that sound. Having worked on more than 800 modern Aeolians, I discovered a way to easily reduce valve travel to an acceptable level and significantly reduce the amount of effort needed to foot pump the unit.
This is so simple, I almost hate to give it away. I take a punching of tan pneumatic leather, exactly the same size as the sponge neoprene valve, prick a hole in the center, apply a small dot of Sobo to the top of the valve stem and push the punching through the exhaust port and on to the top of the valve.
The reduction in valve clearance (from .012 to .015 less than the original clearance) and the leather to plastic seal makes the valve much more quiet and significantly reduces the amount of effort required to foot pump the unit. And my customers love me (well they like me a lot).
Musically, John A. Tuttle (johntuttle@playercare.com)
Visit my Virtual Domain at: www.playercare.com |
(Message sent Thu 27 Feb 1997, 04:09:11 GMT, from time zone GMT-0800.) |
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