Hi All, for over six months via email I've been helping an 81-year-old
gentleman who has been working on his Aeolian Technola Metrograde
player piano. Looking through the MMD Archives, there's only mention
of a 65-note Technola and no mention of a Metrograde.

His piano, which is all original condition, plays 88-note rolls. It
has both automatic and manual (not pushbutton) sustain. It also has
a Ritardando/Accelerando feature built into the Tempo Control/Air Motor
Governor Box.

What's also a little unusual is that the Bass and Treble Soft controls
manually control the position of the split hammer rail. Roll tracking
is accomplished by a single finger tracker and bellows. This is what's
more commonly referred to as a 'bleeding tracker'.

Now to my primary concern about this system. As mentioned previously,
the system has both manual and automatic sustain. However, unlike most
automatic sustain systems which employ a simple sliding On-Off switch
in the spoolbox for controlling the signal to the valve in the sustain
device, this system has a secondary valve box mounted to the left of
the sliding switch.

Although I can't be certain, it's my feeling that this valve box is
a sort of 'amplifier'. That's because the hose that's connected to the
trackerbar is regular trackerbar tubing, which, if you look closely to
the picture of the Sustain Valve Box, is connected to a short piece of
7/32" tubing before getting connected to the On-Off Switch.

From the switch, the control tubing gets connected to what appears to
be the pouch in the sustain valve box. In the bottom left corner of
the composite picture, I've marked the two other elbows A and B and
a hole in the box is marked C.

Unfortunately, the owner is very reluctant to take the sustain valve box
apart to see what's inside, but logic tells me that the hose marked B is
for supply vacuum and the hose marked A goes to the valve in the sustain
device (in the bottom of the piano). By the way, both hoses go down to
the bottom half of the piano and there is an elbow on the Action Cut-Out
Box to supply vacuum to the Sustain Valve Box.

What's got me scratching my balding head is the type of valve inside the
Sustain Valve Box. My inclination is to say that it's a primary type
valve. Does anyone know for sure which type of valve it is?

By the way, I've also created a tubing diagram for the system.

Musically,
John A Tuttle
Player-Care
Brick, NJ, USA

 [ Composite pictures of Technola/Metrograde system
 [ https://www.mmdigest.com/Attachments/23/05/29/230529_073054_composite.jpg 

 [ Aeolian Technola/Metrograde Tubing Diagram
 [ https://www.mmdigest.com/Attachments/23/05/29/230529_073054_tubing-diagram.jpg 

 [ Later -- ] 

Hi All, Regarding the Aeolian Technola Metrograde player system,
the customer opened the Sustain Valve Box. The valve is indeed
a primary type valve.

 [ Aeolian, Technola Piano, Metrograde Sustain Valve Box
 [ https://www.mmdigest.com/Attachments/23/05/29/230529_154546_sustain-box.jpg 

John A Tuttle 

 [ At https://repository.library.brown.edu/studio/item/bdr:697533/PDF/ 
 [ citing Ord-Hume: "Pianola: The History of the Self-Playing Piano",
 [ page 161:
 [ 
 [ "In 1914, Aeolian improved on their lever system (the ergonomic
 [ ignorance of which Ord-Hume bemoans) by adding additional tempo
 [ buttons called the Metrograde."
 [
 [ At https://www.mmdigest.com/Smythe/Aeolian_Hall_Grand_Opening.pdf 
 [ "Technola Player Piano Department
 [ "THE TECHNOLA Player Piano is an instrument which we created to
 [ meet a wide and growing demand for a player piano of Aeolian-quality
 [ construction at a price materially lower than we were able to place
 [ on any of the Pianola Pianos. It consists of a thoroughly artistic
 [ and absolutely reliable upright piano of our own manufacture into
 [ which we build a player action which is also our own in every detail.
 [
 [ "The resulting instrument is a player piano which is excelled in
 [ artistic effects only by the Pianola Pianos themselves, and which is
 [ both musically and constructionally superior to other instruments
 [ sold for a great deal more. Only the enormous resources of our
 [ Pianola factories make the Technola Piano possible at its price.
 [ The display of Technola Player Pianos is located on the third floor
 [ mezzanine.
 [
 [ "Technola Player Pianos, $450 and $475."
 [
 [ -- Robbie