Dick, you wrote in MMDigest 981026:

> I have an Ampico B and I got to wondering if PowerRoll had a way of
> being told whether it is playing the A and B Ampico rolls coded on
> the CDs  on an Ampico A or an Ampico B?  The reason I was wondering
> about this is because the Ampico B intensities react quicker than the
> Ampico A intensities. ...
>
> The folks at Ampico dealt with this by very slightly off-setting the
> intensity & cancel holes in the trackerbar down below (or past) the
> line of note holes.  The expression perforations on a moving A or B
> roll would then arrived a fraction later ...

Wayne Stahnke believes that the reason for the displaced holes in the
B tracker bar is not to alter the timing, but because the ball-check
valve requires more area of the tracker-bar hole to be exposed before
the note valve operates (in comparison to the A piano).

In other words, the intent of displacing the holes in the tracker bar
was not to delay (in time) the intensity commands, but so that more
of the note hole is exposed compared to the intensity hole.  (They
couldn't make the note holes larger or the repetition would suffer.)

Perhaps you could try this test:  Locate a music roll which has a few
note holes punched in the same (perforator) row as a single intensity
control hole (like #2 or #4).  With the B tracker bar the note will
_appear_ visually to play before the intensity command, and so it
wouldn't respond to the accent.  However, the note valve and the
intensity valve should turn on at the same position of the paper;
at this point you should see that the intensity valve operates with
relatively little tracker bar hole exposed, while the note valve
requires appreciably more exposed area.

I hope we'll have an article from Wayne describing how he tested this
phenomenon on a B Ampico, and why he concluded that no compensation is
needed when the Ampico B valves are controlled by electric magnet
valves.  It's a fascinating notion!

Robbie Rhodes