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MMD > Archives > July 1998 > 1998.07.21 > 17Prev  Next

PowerRoll Construction
By Mike Ames

[ Mike Ames shares this letter with MMD.  Tom Jansen, of Monschau,
 [ Germany, is experienced with both electronic and pneumatic systems,
 [ and has assisted at both the Milhous museum in Florida and at
 [ Siegfried Wendel's museum in Rudesheim.  I hope we can entice him
 [ to join the fun at MMD!  -- Robbie

> Dear Mike,  Here again is my question about the PowerRoll system
> offered from Broadmoore Research Corporation.  Is this the person who
> was busy experimenting with a setup to go right on the tracker bar?
> We talked about it in Florida.  Have you seen or tried such a unit?
> I am really interested to know about it.
> I am definitely planning to come to California in Autumn to see you.
> Too much work over here, so I will not come to the Charlotte MBSI
> meeting.  Sigh...
> All the best from Monschau,
> Tom

Hi Tom,   Yes, Larry Broadmoore is manufacturing the PowerRoll System.
I have assisted and tested his development of the electro-magnet valves
from the beginning, offering suggestions on the valve design.

His MIDI decoder is designed by Laurent Coray of Octet Design Corp.
I have also worked with Laurent and he is a highly competent engineer
and manufacturer.  He currently sells the best and least expensive MIDI
decoders.  His web site is

The PowerRoll appears as a rectangular box 3" x 2" x 11" which resides
in the space where the roll normally goes.  It is supported by two
adjustable/fixed arms which attach to the original roll chucks to
locate the unit.  When mounted it is free to swing/pivot about the
axis of the roll chucks.

Now imagine one side of the box extended outward in the plane of that
side, such that as the box is rotated, the elastomer under surface of
this flange swings down against the tracker bar.  On the under-side of
the flange there are 100 holes which are sealed to the tracker bar by
the elastomeric gasket.

This 11" flange is a little less than 1/4" in thickness so that in
Ampico grands the drawer will still close.  These holes in the flange
communicate back to the box and connect to 100 electro-magnetic valves.

Upon opening the box you will see several layers of rather different
technologies.  First is a layer of electronics (the decoder) mounted
on a printed circuit board.  The electromagnets are soldered onto a
second PC board below the decoder board.  The next layer is a very
clever and complex assemblage of valve armature, spiral leaf spring,
and elastomeric vacuum seal, which opens and closes the 100 passages
from the tracker bar.

I have installed the system several times on my Mason and Hamlin
grand, and on a friend's Chickering upright.  It worked very well.

Larry has teamed up with Wayne Stahnke, who is selling about 450
Ampico recordings on a CD to play through the PowerRoll System.
In case you don't know him, Wayne Stahnke is the inventor of the
modern-day electronic reproducing piano.  His early work and patents
led the way for all the others.

I should add that Laurent is designing a multi-use disk player that
will accept floppy or CD input, and a radio link with the Power Roll.
There is also a provision to automatically turn the piano on and off.

That's probably more than you needed to know about the PowerRoll, but
I am impressed with the system.  Its assembly does require accurate
jigging, attention to detail, and exacting manufacturing skills.

We are looking forward to your visit.  Please plan to vacation in
San Diego and stay with us here at Solana Instruments.

Good Luck,  Mike

(Message sent Wed 22 Jul 1998, 02:29:46 GMT, from time zone GMT-0700.)

Key Words in Subject:  Construction, PowerRoll

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