[ Rick Bourgeois wrote in 140904 MMDigest
> Does anyone know where I can buy valve seats/plates to replace
> the cross type for a Duo-Art?
Regarding replacement of Duo-Art cross valves, don't do it -- they are
a superior design and are fine to use. The Duo-Art in Steinway pianos
used cross valves well after Aeolian switched to the valve plates with
the round holes because I believe they could play with greater
sensitivity. I think the cross design allows the valve to more easily
lift off the seat as there is a smaller surface area drawing down on
the valve, which is quite heavy, and the lift at low vacuum levels is
a potential issue.
It's just my own theory here but I have never replaced any cross
valve plates in all these years and have even re-installed a set that
was replaced with the ones Durrell Armstrong made up to replace them.
Those particular replacement plates worked very poorly at low vacuum
levels for the reason explained above.
Duo-Arts also have shallow pouch wells. I guess if they were deeper
the pouches would have more lift strength. But as the system is built
is just perfect and the cross valve stacks work great.
Ben Gottfried - Ben's Player Piano Service
Richfield Springs, New York