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Probably one of the hardest parts of constructing our toy organ is finding a tuning method. One proven method is to use an electric organ. However, many of these are unstable and may have drifted. The Hammond B3 or C3 is a good instrument to use. With the highest drawbar pulled out only, the following notes, starting with the low F, closely agree with the frqUencies specified.

F5 697 Hz.
A6 880 Hz.         A better idea is, of course, to use an accurate
C#6 1108 Hz.       signal generator. If the generator is off, you
E6 1318 Hz.        can calibrate it by using A = 880 Hz. Or, Ma Bell
F#6 1479 Hz.       herself can help you. A touch tone phone operates
G#6 1661 Hz.       very accurately with each row and column having
E7 2637 Hz.        a single frequency. To get 697 Hz, simply press
                   any two buttons on the top row.

To tune a signal generator with a touch-tone phone, connect the generator output to the two microphone terminals in the phone handset, press 1 and 2, and tune generator until "beats" stop. Generator is now putting out 697.

Several YIPLs have written us that the original oscillator schematic has unnecessary parts for temperature stability. We have found that best results necessitate these parts because pay phones are often in cold parts, and one would not want to call a friend long distance just to play him an out-of-tune organ, now would we?

Published for informational purposes only by Youth Hot Line Reports, Inc.

For those of you who are interested in obtaining the original information on boxing, the Bell System Technical Journal, in 1960 or in 1961, put out an article called Multifrequency signaling systems. You might find it in an engineering library, if Bell doesn't find it first. We would appreciate it if an astute YiPPler would go there armed with a razor blade, and after liberating the article, send it to us for publication. We will return it to her/him.

A subscription to YIPL costs $4/yr. if you got.
TAP Room 418 , 152 W. 42 St. N.Y. N.Y. 10036


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