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MMD > Archives > January 2000 > 2000.01.17 > 11Prev  Next

Reducing Turbine Noise in Dynavoice Keytop Player
By Tom Lear

Howdy MMDer's,  Here's something for the Dynavoice archives, for the
other two people on the planet that might ever rebuild a Dynavoice.

I have pretty much completed my rebuild I've been working on since July
1999.  All the vacuum chambers have been opened and the pouches resealed
or replaced, the top valve faces re-lined, loose tubing replaced, etc.
The result being elimination of much leakage in the system so that the
internal turbine can be run at the slowest possible speed, which keeps
the exhaust temperature down to a reasonable level and the noise almost

The biggest complaint about the Dynavoice is the turbine noise.  I have
three fixes to reduce the noise.  One eliminates it altogether and is
a simple fix.

(1)  Rebuild as above, eliminating all leaks.

(2)  Line the inside of the covers with 1/16" felt to baffle the turbine
noise and vibration from being amplified and/or transmitted by the

(3)  Best of all -- Seal the two rod holes and the motor wires hole
of the turbine cover with tape.  Also tape the end of the motor cover
where it meets the left end frame gasket to eliminate all leaks.
Insert a fitting into exhaust outlet that will accept a standard vacuum
handle.  Make it air tight.  Install a SPST switch just ahead of the
turbine.  Install a plug receptacle in the circuit controlled by the
turbine speed control (the volume control).

Now, all that's needed is about 30 feet of vacuum hose and a standard
household tank vacuum.  Place the vacuum in another room, in the
basement or outside, etc.,  wherever it's far enough away to not
impinge on your eardrums.  Plug the external vacuum into the plug
receptacle that's controlled by volume control, attach the vacuum hose
to the exhaust fitting of the Dynavoice turbine.  Turn the Dynavoice
turbine off (the SPST switch you installed earlier) and enjoy turbine-
noise-free music!

Tom Lear
San Francisco CA

(Message sent Mon 17 Jan 2000, 23:49:34 GMT, from time zone GMT-0500.)

Key Words in Subject:  Dynavoice, Keytop, Noise, Player, Reducing, Turbine

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