Demonstration of the Electric
Vacuum Pump Kit sold at

Occasionally, people will ask about the safety and quietness of the pump kit. And, sometimes a picture can be worth a thousand words. While that is not entirely true in this case, the picture at the right does make it easier to understand why the pump is both safe and quiet.

After years of testing (since the early 70's), the one aspect of building a quiet pump that stands out above all other aspects is noise dampening. For many years, the pump motor was supported by moderately soft rubber that had very little compressibility. While this was convenient, it still allowed the vibration of the motor to be transferred to the wooden box -which for many years was made out of plywood. (We'll talk more about that shortly.) However, as newer rubber and synthetic rubber compounds were invented, it was found that softer, more compressible seals and supports reduced the transfer of vibrations significantly. Now, the top seal is made of a soft, compressible sponge rubber that provides excellent air-tightness and a soft cushion. All around the perimeter of the motor, a very soft 1/2" sponge rubber lines the walls of the box to reduce the high-pitched noise created by the brushes and commutator as well as reducing the noise created by the rushing of air over the blades of the turbine (inside the motor). Next, the bottom motor support is comprised of three stages of dampening. The first stage is the thin fiber disk which dissipates the noise created by the bearing over a broad area. Below that is a relatively firm sponge rubber pad which absorbs the noise. Underneath the pad is the support platform. It is in this area that significant improvements have been made within the past few years. In prior models, the platform itself was only 3/8" plywood. Now, it is made out of 1/2" thick particle board, and the motor box is made out of 3/4" particle board (except the front, which is made out of plywood for strength). It was discovered that particle board, with its millions of minute spaces between the particles of wood, absorbs (or traps) noise better than solid wood or plywood. Under the platform are two more strips of particle board that are lined on the bottom with the same sponge rubber used to line the walls of the box. Lastly, there's a swatch of carpet material stapled to the bottom of the pump. It serves two purposes. One, it helps isolate any vibrations in the pump box from the bottom of the piano, which acts somewhat like a soundboard. Two, it provides a surface to which an adhesive can be applied to secure the pump box in place, insuring that it won't move during shipping. Together, these features eliminate virtually all of the motor noise. Further, the design of the platform forces the air moving across the turbines (which creates about 90% of the noise of a vacuum pump) to change direction, which helps decreases the noise of the moving air. For safety, all of the wood and sponge rubber near the motor are lined with fire-resistive foil.

NOTE: Applying an external vacuum source to a player system via a "T" fitting can only be done in a few player systems. Namely the Simplex and early Aeolian players. Almost all others have devices inside the exhauster assembly which control the flow of vacuum to the stack, air motor, and air motor governor (and other peripheral devices -if there). A better alternative to drilling a hole in the reservoir is making a new spring access panel. Most reservoirs have a spring access panel on the front or back of the reservoir. So, you can remove and save the old one for when you want to return the system to its original state.

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