Hi All, A couple of weeks ago I bought a shop vac at Wal-Mart for
about $40.00. I suppose a clever person could remove the vacuum pump
from such a unit and then build a box to house the pump. Then, to
control the vacuum level, he could go to the hardware store and buy
a $6.00 light dimmer switch and hook it in series with one side of the
AC line. Throw in a couple of PVC fittings, which are also available
at the hardware store for a few bucks, and you have your basic "Vacuum
Pump Kit" for a player piano, for less than $60.00.
Would I recommend such a system? Not on your life! Why? Because it
wasn't designed for use in a player piano.
Those of us in the trade have seen systems similar to the one
described above. One technician in the New York area use to install
mini "Premier MV2" vacuum cleaners in player pianos. He mounted the
small 12"x7"x5" device on the side wall (in the bottom of the piano)
and then wrapped it with fiberglass insulation to reduce the noise
Since no effort was made to baffle or filter the exhaust, it ultimately
blew fiberglass all over the inside of the piano. Ultimately, the
particles got into the valves and the system died a horrible death --
which cost the customer thousands of dollars.
The good vacuum pump systems that are available for player pianos today
are expensive for a reason. To begin with, the pumps are specifically
designed for quiet operation. I won't explain how this is done, but
the motor and turbines are quite different from what you find in
a vacuum cleaner or shop vac. Also, the motor is protected from
overheating by a thermal protection circuit.
The vacuum level control circuitry, while similar to that found in a
light dimmer switch, is also specifically designed to provide years of
faithful service across a wide range of voltages. This is extremely
important because the vacuum level required for a well-operating player
is typically very low. This means that the motor will be running at
a very slow speed, and here again overheating becomes a problem. Also,
player pianos normally require two different vacuum levels. One for
the Play cycle, and one for the Rewind cycle. That's why a good pump
system has a dual-stage controller and a sensing switch that tells the
controller which cycle is in use.
Lastly, a good pump system has a good guarantee. The best system
available today has a one-year guarantee on the electronics and
a five-year guarantee on the pump. When you put this all together,
it's easy to see why a good system is relatively expensive, and worth
John A Tuttle
Brick, New Jersey, USA