GB1596577A

GB1596577A - Enhanced sound reproduction from gramophone records

Info

Publication number: GB1596577A
Application number: GB5089/78A
Authority: GB
Original assignee: MILTY PRODUCTS Ltd
Current assignee: MILTY PRODUCTS Ltd
Priority date: 1978-02-08
Filing date: 1978-02-08
Publication date: 1981-08-26
Also published as: IT1110419B; DK420179A; BE873988A; JPS55500342A; NL7900896A; EP0010094A1; WO1979000603A1; IT7920023A0

Abstract

A method of and a means for alleviating the adverse effects of electrostatic charge and of the electrostatic field arising therefrom on a gramophone record during the playing thereof is proposed which involves the simultaneous emission both of positive and negative ions to the space above the record by respective emission electrodes (13, 14) disposed adjacent to the periphery of the record, there being a differential between the voltages applied to the respective emission electrodes and the positive electrode preferably being located in advance of the negative electrode in the direction of record rotation so as to be met first by any particular part of the disc periphery.

Description

(54) ENHANCED SOUND REPRODUCTION FROM GRAMOPHONE RECORDS (71) We, MILTY PRODUCTS LIMITED, a British Company of 223 Chapel Street, Salford, Lancashire M3 SEQ, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention concerns the alleviation of the adverse effects of electrostatic charges present on gramophone records.

According to the present invention there is proposed a method for the alleviation, during the playing of a gramophone record, of the adverse effects on sound reproduction of any static charge on the surface of the record, and of the electrostatic field arising from such charge, the method comprising the step of creating, in the space above the said surface, an array of positively and negatively charged ions by simultaneous emission of positive and negative ions from separate positive and negative ion emission means thereby to effect the neutralisation or substantial neutralisation of the said electrostatic field, the positive ion emission means being maintained at a substantially higher voltage than the negative ion emission means.

According to a preferred feature, the positively charged and negatively charged ions are emitted both continuously and simultaneously by respective such means.

The invention also contemplates apparatus for practising the method as aforesaid and which includes first and second ion emission means adapted respectively and simultaneously to emit positively charge and negatively charged ions into the space above the surface of a record located in position on the record player to create an array of positively charged and negatively charged ions above the said surface for the neutralisation or substantial neutralisation of the electrostatic field arising from such charge and the alleviation of the adverse effects on sound reproduction of any static charge on the surface of the record and the electrostatic field arising from such charge, the first ion emission means being arranged to operate at a substantially high voltage than the second ion emission means The invention will now be described further by way of example only, with reference to the accompanying drawing illustrating one embodiment thereof, and in which: Fig. 1 is a diagrammatic side elevation of a device constructed in accordance with the invention as positioned for use relative to a record disc on a gramophone turntable; Fig. 2 is a perspective view of the device shown in Fig. 1; and Fig. 3 is a diagrammatic perspective view of the pins of the device of Figs. 1 and 2.

Referring now to the drawings, a device for the neutralisation or substantial neutralisation of the electrostatic field arising from an electrostatic charge at the surface of a record disc 11 on a gramophone turntable 12 comprises spaced electrodes 13, 14 arranged in side-by-side disposition within a box 15 mounted adjacent the said turntable, the electrodes 13, 14 being connected with respective high voltage sources via leads 16, 17.

The electrodes 13, 14 each comprise a pm of 38's gauge wire, such pins being approxí- mately two and a half centimeteres long and being mounted in parallel disposition at one and a half-centimetres centres in a Perspex (Registered Trade Mark) block to extend forwardly therefrom by approximately threequarters of their length. The rearward ends of the pins are connected with the respective leads 16, 17 directly adjacent the back of the block.

The box 15, which box is conveniently fabricated from synthetic plastics material, for example ABS, is of rectangular form, and has a window at its forward end, the pins being arranged perpendicular to the plane of the window respectively to emit positive and negative ions therethrough, and the perspex block being secured to the box with the fov ward ends of the pins positioned rearwardly of the window.

In order to provide for the ready veBiçal adjustment of the box relative to the plane of the record disc, such box is mounted on a base plate 18 by means of an articulated linkage 19, such linkage being so connected with the base plate 18 or box 15 as to provide for a relative rotation between the box and base plate if desired. The device may be freestanding relative to the turntable 12 or may be secured in position relative thereto, the base plate, in the former case, preferably being weighted for stability purposes.

In a typical situation the device is positioned adjacent the periphery of the record disc 1 say two and a half centimetres from the line of such periphery, with the common plane of the electrodes 13, 14 approximately one and a quarter centimeters above the plane of the disc, and the electrodes are connected with a positive source of 4.43 KV and a negative source of 3.55 KV respectively. The electrode emitting the positive ions is preferably placed forwardly of that electrode emitting the negative ions in the direction of disc rotation, it having been found that such disposition gives an improved performance as compared with the alternative disposition.

We have found that by means of the device as hereinbefore described we are able to create a space above the revolving disc of substantially neutral charge, and accordingly effectively inhibit the ingress of dust and the like to such space, and thus to the surface of the record.

The disposition of the device in relation to the plane of the disc does not appear to be critical, and indeed advantageous effects have been achieved when the plane as defined by the pins is slightly below the plane of the disc, the device being located outwardly of the periphery thereof It has been established that the pins will produce satisfactory effects if arranged one above the other, rather than in the side-byside disposition shown, and thus the invention is not to be considered limited to the disposition of pins shown.

Whilst the device as hereinbefore described represents a convenient, effective and aesthetically pleasing structure for reducing contamination of the playing surface of the revolving disc by dust, for minimising variations in the weight trackability of the pick-up arm and stylus and for alleviating other problems which would arise from an electrostatic charge at the record surface, such device represents but one of a variety of means embodying the invention.

Thus, for example, instead of providing a pair of pins emitting positive or negative ions, alternative forms of emitter may be used. In one arrangement, there may be a row of from two to twelve pins arranged at, say, two and a half centimeters centres for the emission of positive ions and a further similar row of pins for the emission of negative ions, the two rows being arranged in parallel disposition and lying in respective planes parallel or perpendicular to the plane of the disc and, in the former case, tangential to such disc.

In another arrangement, each emitter takes the form of a rod or wire arranged tangentially of the disc or perpendicular to the plane thereof and in spaced disposition relative to the periphery of the disc, wire lengths of between two and a half and thirty centimetres having given satisfactory results.

It may be found convenient, and indeed economically advantageous to build the device into the turntable deck, thereby minimising or eliminating the need for additional structure specifically to support the emitters.

Like voltages to those referred to in connection with the device illustrated in the drawing, and indeed a range of voltages at either side thereof, will give substantial neutralisation of an electrostatic field arising from the disc surface to provide satisfactory results.

Whilst the invention has been disclosed in the context of the simultaneous emission of positive and negative ions, such invention is not limited to simultaneous emission in the sense of continuous emission both of positive and negative ions at one and the same time as in the case of the embodiment hereindisclosed. In its broadest sense the inventive concept is seen to lie in the use both of positive and negative ions to neutralise the field arising from the electrostatic charge present on the record.

WHAT WE CLAIM IS:- 1. A method for the alleviation, during the playing of a gramophone record, of the adverse effects on sound reproduction of any static charge on the surface of the record, and of the electrostatic field arising from such charge, the method comprising the step of creating, in the space above the said surface, an array of positively and negatively charge ions by simultaneous emission of positive and negative ions from separate positive and negative ion emission means thereby to effect the neturalisation or substantial neutralisation of the said electrostatic field, the positive ion emission means being maintained at a substantially higher voltage than the negative ion emission means.

2. The method as claimed in claim 1, wherein positively and negatively charged ions are emitted both continuously and simultaneously.

3. The method as claimed in any one of the preceding claims, wherein the source of ions is disposed adjacent the periphery of the record to emit an array of ions across the surface of the record.

4. The method as claimed in claim 1, wherein positively charged and negatively

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. adjustment of the box relative to the plane of the record disc, such box is mounted on a base plate 18 by means of an articulated linkage 19, such linkage being so connected with the base plate 18 or box 15 as to provide for a relative rotation between the box and base plate if desired. The device may be freestanding relative to the turntable 12 or may be secured in position relative thereto, the base plate, in the former case, preferably being weighted for stability purposes. In a typical situation the device is positioned adjacent the periphery of the record disc 1 say two and a half centimetres from the line of such periphery, with the common plane of the electrodes 13, 14 approximately one and a quarter centimeters above the plane of the disc, and the electrodes are connected with a positive source of 4.43 KV and a negative source of 3.55 KV respectively. The electrode emitting the positive ions is preferably placed forwardly of that electrode emitting the negative ions in the direction of disc rotation, it having been found that such disposition gives an improved performance as compared with the alternative disposition. We have found that by means of the device as hereinbefore described we are able to create a space above the revolving disc of substantially neutral charge, and accordingly effectively inhibit the ingress of dust and the like to such space, and thus to the surface of the record. The disposition of the device in relation to the plane of the disc does not appear to be critical, and indeed advantageous effects have been achieved when the plane as defined by the pins is slightly below the plane of the disc, the device being located outwardly of the periphery thereof It has been established that the pins will produce satisfactory effects if arranged one above the other, rather than in the side-byside disposition shown, and thus the invention is not to be considered limited to the disposition of pins shown. Whilst the device as hereinbefore described represents a convenient, effective and aesthetically pleasing structure for reducing contamination of the playing surface of the revolving disc by dust, for minimising variations in the weight trackability of the pick-up arm and stylus and for alleviating other problems which would arise from an electrostatic charge at the record surface, such device represents but one of a variety of means embodying the invention. Thus, for example, instead of providing a pair of pins emitting positive or negative ions, alternative forms of emitter may be used. In one arrangement, there may be a row of from two to twelve pins arranged at, say, two and a half centimeters centres for the emission of positive ions and a further similar row of pins for the emission of negative ions, the two rows being arranged in parallel disposition and lying in respective planes parallel or perpendicular to the plane of the disc and, in the former case, tangential to such disc. In another arrangement, each emitter takes the form of a rod or wire arranged tangentially of the disc or perpendicular to the plane thereof and in spaced disposition relative to the periphery of the disc, wire lengths of between two and a half and thirty centimetres having given satisfactory results. It may be found convenient, and indeed economically advantageous to build the device into the turntable deck, thereby minimising or eliminating the need for additional structure specifically to support the emitters. Like voltages to those referred to in connection with the device illustrated in the drawing, and indeed a range of voltages at either side thereof, will give substantial neutralisation of an electrostatic field arising from the disc surface to provide satisfactory results. Whilst the invention has been disclosed in the context of the simultaneous emission of positive and negative ions, such invention is not limited to simultaneous emission in the sense of continuous emission both of positive and negative ions at one and the same time as in the case of the embodiment hereindisclosed. In its broadest sense the inventive concept is seen to lie in the use both of positive and negative ions to neutralise the field arising from the electrostatic charge present on the record. WHAT WE CLAIM IS:-

1. A method for the alleviation, during the playing of a gramophone record, of the adverse effects on sound reproduction of any static charge on the surface of the record, and of the electrostatic field arising from such charge, the method comprising the step of creating, in the space above the said surface, an array of positively and negatively charge ions by simultaneous emission of positive and negative ions from separate positive and negative ion emission means thereby to effect the neturalisation or substantial neutralisation of the said electrostatic field, the positive ion emission means being maintained at a substantially higher voltage than the negative ion emission means.

4. The method as claimed in claim 1, wherein positively charged and negatively

charged ions are emitted from separate emission means arranged in side-by-side disposition adjacent the periphery of the record, the positive ion emitter being positioned forwardly of the negative ion emitter in the direction of record rotation.

5. Apparatus for use in practising the method claimed in claim 1 including first and second ion emission means adapted respectively and simultaneously to emit positively charged and negatively charged ions into the space above the surface of a record located in position on the record player to create an array of positively charged and negatively charged ions above the said surface for the neutralisation or substantial neturalisation of the electrostatic field arising from such charge and the alleviation of the adverse effects on sound reproduction of any static charge on the surface of the record and the electrostatic field arising from such charge, the first ion emission means being arranged to operate at a substantially higher voltage than the second ion emission means.

6. The apparatus as claimed in claim 5, wherein the separate emission means are arranged in side-by-side disposition.

7. The apparatus as claimed in claim 5 or 6, wherein the emission means for emitting positively charged ions is positioned forwardly of the emission means for emitting negatively charged ions in the direction of rotation of the gramophone record.

8. The apparatus as claimed in any one of claims 5 to 7, wherein the position of the emission means is adapted to be adjustable relative to the plane of the record

9. Apparatus as claimed in any one of claims 5 to 8, wherein the separate emission means are provided in a common housing mountable adjacent the periphery of the record.

10. Apparatus as claimed in claim 9, wherein the housing is angularly adjustable about an axis perpendicular to the plane ofthe record.

11. Apparatus as claimed in claim 9 or 10, wherein the housing forms part of the structure of the record player.

12. The method for the alleviation, during the playing of a gramophone record, of the adverse effects on sound reproduction of any static charge on the record and the electrostatic field arising from such charge substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

13. Apparatus for the alleviation, during the playing of the record, of the adverse effects on sound reproduction of any static charge on the record and the electrostatic field arising from such charge substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

14. A gramophone record player having apparatus for the alleviation, during the playing of the record, of the adverse effects on sound reproduction of any static charge on the record and the electrostatic field arising from such charge as claimed in any one of claims 5 to 11 and 13 or operating in accordance with the method claimed in any one of claims 1 to 4 and 12.