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MMD > Archives > November 1998 > 1998.11.03 > 12Prev  Next

Ampico Model B Trackerbar
By Craig Brougher

Interesting that I have never noticed this, but actually, all the
expression holes at each end of the Ampico B trackerbar have been
offset from the centerline of the bar by about .02 inch.  The only
hole in that line which seems to still be aligned with the note hole
line is TB#5.  In other words, the motor switch timed hole.  So it
isn't so the eye can find it, after all!  Ha-ha.

When I first looked at this alignment again I just glanced at my own
bar, but I decided to measure more closely and used a bar that I could
put on my bench and get a good reading on.  So I learned something.
Very curious.  The offset would only give the note line a time advan-
tage of about 1 perforator step.  Or, looking at it another way, the
offset would drop back the timing of all expressions 1 perforator step.

There can be one explanation for this offhand: It is very precision
timing compensation for model A rolls, whose expressions were led one
step too long, ahead of what an Ampico B would require.

I am glad someone asked that question.  This may be the reason for the
tiny offset.  I have a hunch then that the compensation correcting the
B for expression timing in Ampico rolls is drilled right into solid

Craig Brougher

(Message sent Tue 3 Nov 1998, 14:17:34 GMT, from time zone GMT-0600.)

Key Words in Subject:  Ampico, B, Model, Trackerbar

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