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June 17 Ampico perforator studyMany thanks to all of you who have helped support the IAMMP archive by contributing your roll scans. Although it might appear the author has been inactive, in fact, a great deal of important work has been going on behind the scenes. I have just returned from a very successful week-long visit to the Keystone Music Roll Company. Over the past several months, Richard Groman, Frank Thompson, myself and Larry Chase have collaborated on the implementation of a MIDI interface to one of the original Ampico perforators. The purpose of this most recent trip was to select the appropriate gears for cutting rolls having pull-through rates other than 30:1. I made measurements of the existing gear ratios, the reduction rate of the intermittent transmission and the effective capstan circumference. A digital counter was used to count the revolutions of the punch ram while measuring the distance between two marks on the paper. This yielded a precise figure of the actual pull-through rate. I then created an Excel spreadsheet which allows for repeated measurements of the pull-through rate whenever there is a change in paper thickness or the number of copies being cut. This spreadsheet allows alternative change gears to be specified and the resulting pull-through rate is displayed. Using the established pull-through rate, the length of a punch master file can be input in the form of Measures, Beats and Ticks. Repeated testing was done with several punch master files and we have found the calculator to be able to predict the actual length of the roll to be cut within an accuracy of better than 1.5" for a 30 foot roll. I added an input field for the measured length of the original roll and the deviation is displayed as well. This allows for some additional gear combinations to be tried in order to match the predicted length of the copy to the original. After some new gears arrived, we had excellent results cutting 20:1 rolls and many of these will appear in the next Keystone catalog.
We assembled the tractor feed mechanism to the original Aeolian perforator and threaded one of the surviving cardboard stencils for the photo in this weeks album. Among the surviving cardboard stencils, Richard found an unissued Paderewski recording. It appears to contain Ampico expression coding and is similar to the DuoArt roll shown in the photo. I have accepted the challenge of remastering this roll. The DuoArt roll will be scanned, a punch master will be rendered and the DuoArt expression tracks will be manually replaced with the Ampico expression coding from the cardboard stencil. No one knows if the original stencil was ever finished, but we will soon hear the results! Many people are not aware, a great many of the late Ampico popular rolls were punched on the Aeolian perforator with the cardboard stencils. Hence the need for scanning and digitally remastering the popular rolls.
As the newest member of the Keystone team, I have been helping to scan many of the titles which will appear in the upcoming catalog. I have also brought home a couple boxes of hot titles to scan for the Winter catalog. New die sets have been ordered for both Ampico perforators and full production will resume once they arrive.
In order to better control the punch-for-punch accuracy of the product, Richard has been kind enough to lend me one of the late Aeolian perforating machines which will be fitted with the same microprocessor and relay as the Keystone Ampico perforator. This perforator will be used to punch proof-copies which will be compared with the original rolls. Comparisons have already been done at the Keystone facility and we have gained a high degree of confidence that the remastering software is producing accurate results. All titles punched last week were auditioned on the Knabe Ampico-B piano with outstanding performance quality. |
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