US3480719A

US3480719A - Electronic organ pedal keying circuit with sustain and cancellation of sustain upon playing of subsequent pedal

Info

Publication number: US3480719A
Application number: US648614A
Authority: US
Inventors: Harold O Schwartz; Robert D Barry
Original assignee: Wurlitzer Co
Current assignee: Wurlitzer Co
Priority date: 1967-06-26
Filing date: 1967-06-26
Publication date: 1969-11-25
Anticipated expiration: 1986-11-25
Also published as: GB1187548A; JPS4921654B1; DE1772712A1

Description

Nov. 25, 1969 ELECT Filed June 26, 19

H. o. SCHWARTZ ET AL 3,480,719 RONIG ORGAN PEDAL KEYING CIRCUIT WITH SUSTAIN AND CANCELLATION OF SUSTAIN UPON PLAYING OF SUBSEQUENT PEDAL 67 2 Sheets-Sheet 1 55 40 a 26) D D Is Iva E E f f N T085 /0 y F M 54 5 fl/VPl/F/ER C/ACU/B FEE/QL SWITCHES COM/70/V 107C 4 nun 505mm vzm, (4% {14% Nov. 25", 1969 H. o. SCHWARTZ ET AL 3,480,719

ELECTRONIC ORGAN PEDAL KEYING CIRCUIT WITH SUSTAIN AND CANCELLATION OF SUSTAIN UPON PLAYING OF SUBSEQUENT PEDAL Filed June 26, 1967 2 Sheets-Sheet z \1 I i 2 3 \E \E 2 E A 5 w, I w Q I @E: 7 5 5 5 Q l s T A H"- m V g a I m M a Q \Is' is W l Q m -h "ll United States Patent O US. Cl. 841.26 8 Claims ABSTRACT OF THE DISCLOSURE An electronic organ having a pedal keying circuit using solid state componets to maintain any note that has been played with a sustain of selectable length, with solid state means for immediately cancelling any sustained note upon the subsequent playing of another note.

DISCLOSURE In the playing of a pipe organ, particularly the pedal notes thereof, a rather long time may be necessary for the notes to decay. When a pedal is released, the mechanital connections must operate to close the valve, and this takes a finite time of some length. The vibrations in the air column take some time to decay as the valve is closed, whereby the note hangs on for quite some time after the pedal has been released. For proper organ-like qualities, an electronic organ should also have some means for sustaining a note after the pedal has been released.

On the other hand, it is undesirable to have two pedal notes adjacent to one another, or even nearly adjacent, play at the same time. Adjacent notes produce beats that can be quite objectionable and very unpleasant to listen to.

Thus, in accordance with the present invention, it is an object to provide an improved sustain for electronic organ pedal notes, but with means for immediately cancelling any sustained note upon the subsequent playing of another note.

It is a further object of the present invention to provide an electronic organ pedal keying circuit, with sustain and cancel, utilizing a minimum of electromechanical contacts, whereby to promote quiet operation and long service life.

It is yet another object of this invention to provide diodes in an electronic organ pedal keying circuit for conveying the tone oscillations when biased for conduction by the closing of a pedal switch, in combination with a capacitor for holding the diodes conducting for some time after the switch has been reopened, and further in combination with a transistor for shorting out the sustain capacitor upon the subsequent playing of another note.

Other and further objects and advantages of the present invention will be apparent from the following description when taken in connection with the accompanying drawings wherein:

FIG. 1 is a perspective view of an electronic organ constructed in accordance with the principles of this invention;

FIG. 2 is a block diagram illustrating the circuits of the invention; and

FIG. 3 is a schematic electrical wiring diagram showing certain of the details of the invention.

Referring now in greater particularity to the drawings, and first to FIG. 1, there will be seen an electronic organ constructed in accordance with the present invention, including a case 12 having an upper keyboard 14 and a lower keyboard 16, and a plurality of stop tablets 18 proximate thereto. A pedal board or clavier 20, including a plurality of pedals, is provided. The number of pedals may vary with the type of organ, but a full organ generally has 32 pedals and pedal notes. The pedals in the illustrated embodiment of the invention are pivoted from a support 22 spaced from the remainder of the case of the organ. A swell pedal 24 is pivoted in the case, and a speaker system is disposed behind grille cloth 26, and may comprise a plurality of loudspeakers of one or more sizes.

Turning now to FIG. 2, the organ tone generators specifically, pedal note generators-are shown at 28. The pedal note generators 28 are connected to diode keying circuits 30. The diode keying circuits normally will not conduct, but pedal switches 34 are connected thereto to turn on the proper diodes. A common latch and sustain network or circuit 36 is connected to the diode keying circuits to hold proper diodes on or in conducting condition, as hereinafter set forth.

The output from the diode keying circuits is connected to formant and tone filters 38 by stop switches associated therewith and operated by the stop tablets 18, and these in turn are connected to an amplifier 40. The amplifier is, in turn, connected to the loudspeaker system 42, which, as heretofore noted, is mounted behind the grille cloth 26 and may comprise a plurality of speakers of different sizes or characteristics.

Turning now to FIG. 3, there will be seen a broken line disposed horizontally adjacent the center of the drawing from top to bottom, and identified by numeral 44. It is to be understood that the circuit below this line is a common circuit, whereas the circuits above the line are duplicated, there being one such circuit for each of the pedal notes, i.e., 32 such circuits in the illustrative embodiment.

Starting at the upper left hand corner, one of the key switches 34 is shown, including a movable contact 46 normally spaced from but engageable with a fixed contact 48 connected to B+ potential. The switches may be ordinary electromechanical switches directly actuated by the respective pedals of the pedal clavier 20', but preferably are magnetic switches as disclosed and claimed in the copending application of Thomas A. Lazzaro, Ser. No. 457,963, now Patent No. 3,408,448, entitled Magnetic Keying for Electronic Organs. Each switch 34 is connected to a junction point 50 which leads through a resistor 52, and from thence through a wire 54 to a common point 56. Various of the wires 54 are shown, and there is a total of 32 such wires in the illustrative embodiment of the invention.

Each junction 50 is further connected to the anode of a diode 58, the cathode thereof being connected to a junction 60. The junction 60 is connected to a resistor 62, the resistor being connected to the anode of a diode 63 and the diode cathode being connected through a wire 64 to a common junction or terminal 66, several of the wires 64 being shown, and it being understood that there would be 32 such wires in the illustrative embodiment of the invention.

The common point, junction, or terminal 66 is connected to a junction 68 in the common latch and sustain circuit 36, and this junction is connected to the collector of an NPN transistor 70, the emitter of which is grounded at 72. The base is connected to ground through a biasing resistor 74, and the base further is connected to a junction 76, the latter in turn being connected to the common terminal or junction 56. A capacitor 78 is connected between the

junctions

68 and 76.

The common terminal or junction 66 has a wire 80 connected thereto which leads to a junction 82. This junction is connected through a resistor 84 to ground. It also is connected to a resistor 86 which leads to a junction 88 The junction is connected to a normally closed switch 90 which comprises a LONG SUSTAIN SWITCH. In

addition, the junction 82 is connected through a wire 92 to a normally closed switch 94 which comprises a ME- DIUM SUSTAIN SWITCH. The other side of this switch is connected through a resistor 96 to the junction 88.

The junction 60 is connected through a resistor 98 to the junction 100. This junction is connected to another junction 102, and the two have a large value shunting or sustain capacitor 104 shunted to ground.

This junction 100 is connected through a resistor 106 to the junction 108. This junction is connected to the anode of a diode 110, the cathode of which is connected to the anode of another diode 112, the cathode thereof being connected to a 16-foot generator signal as indicated at 114. This signal will be received from a generator 28, and it will be understood that the pedal generators often are dividers connected to the generators of the keyboard. A shunting capacitor 116 is connected to ground from between the diodes 110 and 112. These diodes normally do not conduct the generator signal, and to this end the generator signal preferably is always at a potential above ground.

The junction 108 is connected to a capacitor 117, and this is connected to a resistor 118 leading to the 16-foot output, and on through the various stop switches to the appropriate ones of the filters 38.

A circuit somewhat duplicative of that just described is provided for the 8-foot pedal notes. Thus, the junction 102 is connected to a resistor 120 which leads to a junction 122. This junction is connected to the anode of a diode 124, the cathode thereof being connected to the anode of a diode 126, and the connection between the two being shunted to ground by a capacitor 128. The cathode of the diode 126 is connected to the 8-foot generator signal 130.

The junction 122 is connected through a capacitor 132 to a resistor 134 leading to the 8-foot output, and on through the stop switches to the appropriate ones of the stop switches and filters 38.

OPERATION In the operation of the above circuit it must be borne in mind that the diodes 110, 112, and 124, 126 are normally nonconductive. To this end, the generator signals preferably are of a square wave configuration, and always above ground. However, it will be noted that even if the signals were to go below ground, the capacitors 116 and 128 would charge up due to any initial conduction of the diodes 112 and 126 to back bias the diodes, and thus to shut them off. The series connection of the pairs of diodes provides greatly more isolation than would be possible with but a single diode.

When any pedal switch 34 is closed, the B+ potential connected thereto is passed by the diode 58 to open or render conductive all of the diodes 110, 112 and 124, 126, and thus to convey the respective generator signals corresponding to the note being played to the respective 16-foot output and 8-foot output. The transistor 70 is normally biased off, whereby the capacitor 104, previously identified as a sustain capacitor and charged through the diode 58, can discharge only through the sustain network forming the right portion of the common latch and sustain network 36. Thus, when the pedal is released and the corresponding pedal switch 34 reopens, the charge on the capacitor 104 holds the diodes 110, 112 and 124, 126 open for some time. The capacitor discharges through

resistors

98 and 62 to the common connection or junction 66, and from thence over the wire 80 to the junction 82. With the sustain switches closed as shown, the

resistors

84, 86, and 96 are in parallel, and there is a rather low resistance path, resulting in a rather short sustain. However, when the MEDIUM SUSTAIN switch 94 is open, the resistor 96 is removed from the circuit, and the discharge path includes resistors 84 and 86 in parallel, these being of greater resistance than the resistor 96, whereby to effect a medium sustain. When the LONG .4 SUSTAIN switch is open, the resistor 86 is also removed from the circuit, and only the resistor 84 (the resistor of highest resistance of the three) remains in the discharge path, whereby the capacitor 104 discharges more slowly to produce a long sustain.

If the capacitor 104 is still charged, whereby the note is still sustaining, when a subsequent note is played, then the B+ potential will be transmitted through others of the wires 54 and 64 to the common connections 56 and 66. The biasing on the transistor 70 thus is changed to render the transistor conductive. This effectively short circuits the connection 66 to ground, and discharges the previously charged capacitor 104 in very short order, thereby cancelling the note that was sustaining.

Various circuit values will be immediately apparent to those skilled in the art. However, to insure completeness of disclosure, the following values are set forth as exemplary, the B+ potential being 23 volts The specific example of the invention as herein shown and described is for illustrative purposes only. Various changes in structure will no doubt occur to those skilled in the art and will be understood as forming a part of the present invention insofar as they fall within the spirit and scope of the appended claims.

The invention is claimed as follows:

1. An electronic organ comprising means providing a source of electric oscillations corresponding to the pedal notes of said organ, output means, means connecting said source to said output means and including a plurality of diode means respectively corresponding to said pedal notes and connected so as normally not to conduct said oscillations, a voltage source of predetermined polarity, a plurality of pedal switches respectively corresponding to said pedal notes and connected to said voltage source and respectively connected to said diode means, said diode means individually being rendered conductive by application of voltage of said predetermined polarity upon operation of a respective pedal switch, a plurality of voltage storage means respectively connected to said diode means and each storing voltage upon conduction of a corresponding diode means to continue that diode means conducting after cessation of operation of the corresponding pedal switch, discharging means connected to said voltage storage means for discharging voltage therefrom at a controlled rate, and solid state means connected to said voltage storage means and normally non-conducting, said solid state means also being connected to said pedal switches and biased for conduction upon operation of any of said pedal switches rapidly to discharge voltage stored by any of said voltage storage means.

2. An electronic organ as set forth in claim 1 wherein said solid state meansis a common solid state means, being connected to all of said voltage storage means and all of said key switches.

31. An electronic organ as set forth in claim 2 wherein said solid state means is a transistor.

4. An electronic organ as set forth in claim 3 wherein the collector of said transistor is connected to said voltage storage means and the base is connected to said pedal switches.

5. An electronic organ as set forth in claim 1 and further including diode means connecting said voltage storage means to said solid state means.

6. An electronic organ as set forth in claim 2 and further including a plurality of diodes respectively connecting said voltage storage means to said common solid state means.

7. An electronic organ comprising means providing a source of electric oscillations corresponding to the pedal notes of said organ, output means, means connecting said source to said output means and including a plurality of diode means respectively corresponding to said pedal notes and connected so as normally not to conduct said oscillations, a voltage source of predetermined polarity, a plurality of pedal switches respectively corresponding to said pedal notes and connected to said voltage source, a plurality of diodes respectively connecting said pedal switches to said diode means and normally non-conducting, said diodes and said diode means selectively being rendered conductive by application of voltage of said predetermined polarity upon operation of a respective pedal switch, a plurality of voltage storage means respectively connected to said diode means and each storing voltage upon conduction of a corresponding diode means to continue that diode means conducting after cessation of operation of the corresponding pedal switch, discharging means connected to said voltage storage means for discharging voltage therefrom at a controlled rate, and a common cancel circuit comprising a normally non-conducting transistor, said transistor having a collector connected in common to all of said voltage storage means, said transistor having a base connected in common independent of said plurality of diodes to all of said pedal switches, said transistor being biased for conduction by operation of any of said pedal switches rapidly to discharge voltage stored by any of said voltage storage means.

8. An electronic organ as set forth in claim 7 and further including a second plurality of diodes respectively connecting said diode means to said transistor collector.

References Cited UNITED STATES PATENTS 1/1966 Holman et al 84l.26 6/1968 Slaats 841.01

US. Cl. X.R. 84-1.01