Reproducing Rolls on 88-note Mechanisms
By John Grant
Hello All,
The discussions on the list in the last several days regarding the playing of reproducing rolls on 88-note instruments reminds me of the way I solved this problem several years ago. For those who have back issues of the AMICA Bulletin, it is documented in the April 1982 issue, page 70. For those who do not, I will attempt to describe it, but this is a case where one picture (diagram) is literally worth a thousand words. If it is still unclear, email me your snail mail address and I will send you a photocopy of the article. The actual photos probably will not reproduce very well, but the words and line drawing diagram should be sufficient.
Materials needed:
- Duo-Art style 8 signal (2 x 4) cut-out block. These are the
gadgets which inhibit or allow the intensity signals to be
passed through from the tracker bar depending on the position
of the Duo-Art Off/On switch. On the 88-note stack Duo-Arts
there was a second unit which inhibited/allowed note numbers
1, 2, 3, 4, 85, 86, 87, and 88, again depending on the position
of the D-A On/Off switch
- Ampico A style "Modify" switch. This is the switch at the top
of the row (in the typical "A" drawer) that has three positions:
Brilliant/Normal/Subdue.
- 4 plastic "y" couplings for tracker bar size tubing.
- 2 #60 drill hole bleed cups
Now, the attempted description. Use section 1 of the cut-out block to inhibit or pass notes # 1, 2, 87, and 88. Use section 2 to inhibit or pass notes # 3, 4, 85, and 86. Number the nipples on the Ampico modify switch as follows: #2 is the nipple which is opened to atmosphere when the switch is in the "Brilliant" position. This is usually the middle nipple in the grouping. #'s 1 and 3 are the other two nipples which are opened to atmosphere when the switch is in the "Subdue" position. Which you label #1 and which you label #3 is unimportant at this point. Now, connect one leg of "y" #1 to a constant (during "Play") source of vacuum such as the primary stack (if present) or the tracking regulator supply. Into the other two legs of this "y" force the two bleed cups and connect each of these legs to two other "y's" (call them #2 and #3.) Connect one leg on "Y" #2 to section 2 of the cut-out block. Connect the third leg of "y" #2 to switch nipple #1. Connect one leg of "y" #3 to section 1 of the cut-out block. Connect the third leg of "y" #3 to one leg of "y" #4. (Are you still with me?!) Connect the two remaining legs of "y" #4 to nipples 2 and 3 of the switch.
Theory of operation: When the switch is in the "Normal" position, none of its nipples are opened to atmosphere and the constant vacuum passes through the bleeds and enters both sections of the cut-out block, raising all the pouches and allowing tracker bar signals for all of the 8 notes to be passed. This is the position to play 88-note rolls. When the switch is in the "Brilliant" position, atmosphere is admitted into the tube which pulls up the pouches in section #1 of the cut-out block which is controlling notes # 1, 2, 87, and 88. Since this is "downstream" from the bleed, the vacuum through the bleed is negated, and the cut-out block inhibits those notes. This is the position to play Ampico rolls. You will still get one spurious note (if you choose to allow it,) that being the "rewind" hole which lines up with normal note #86. When the switch is in the "Subdue" position, both sections of the cut-out block are activated and all 8 notes will be inhibited. This is the position for Duo-Art rolls. Welte rolls (9/inch)can also be played on this position, however, low C, if called for by the roll, will not sound. A more complicated cut-out arrangement would fix this, of course. For one note (and the few Welte's I have to play) I did not bother.
This does away with the bothersome taping of the tracker bar which can itself, in a sensitive mechanism, cause spurious notes. And, there's no messy adhesive residue clean up!
Season's Greetings to all readers. -John Grant
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"Every creative act results from a sudden cessation of stupidity."
-Edwin H. Land, inventor of the Polaroid Land Camera
"Help stamp out and eliminate superfluous redundancy." -Genius
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(Message sent Thu 14 Dec 1995, 07:35:22 GMT, from time zone GMT-0800.) |
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