JP6695532B2 - Pickup cartridge - Google Patents

Description

  The present invention relates to a pickup cartridge, for example, a pickup cartridge that reads an audio signal from an analog record.

  In the reproduction of an analog record, the sound vibration engraved on the analog record placed on the turntable is picked up using a pickup cartridge. This pip-up cartridge is attached to the tone arm, and the voice vibration picked up by the pickup cartridge is transmitted via the cantilever. Then, the sound vibration is converted into electric vibration by the power generating element attached to the cantilever, and the sound is reproduced by the audio device.

  Here, the types of pickup cartridges will be described. The pickup cartridge is classified into a velocity proportional type and an amplitude proportional type.

  There are two types of speed-proportional pickup cartridges: a moving coil type that transmits vibration to the coil and converts the coil velocity displacement into an electrical signal, and a moving magnet type that transmits vibration to the magnet and converts the velocity displacement of the magnet into an electrical signal. .. In this speed-proportional pickup cartridge, it is necessary to attach a coil or a magnet to the cantilever so that the cantilever is housed within the gap of the magnetic circuit, which limits the shape.

  The amplitude proportional pickup cartridge is a crystal cartridge that detects vibration using Rochelle salt. In this amplitude proportional pickup cartridge, the magnitude of vibration given to Rochelle salt is converted into an electric signal. The amplitude proportional pickup cartridge has a simple structure and is suitable for mass production, but has a problem of insufficient frequency characteristics.

  From the above description, it is understood that the speed proportional pickup cartridge is suitable for reproducing an analog record with high sound quality. However, in the speed proportional type, since it is necessary to attach a heavy member such as a coil or a magnet to the cantilever, the weight of the cantilever increases, it is difficult to control the vibration damping rate of the cantilever, and sound quality deteriorates. Therefore, Patent Document 1 discloses a technique for suppressing the vibration of the cantilever.

  The technique described in Patent Document 1 includes a cantilever that has a reproducing needle that traces the groove of the record board R on one end side, and a vibrator that integrally operates on the audio signal output electric converter on the other end side. In a pickup cartridge in which the other end of the cantilever is oscillatably supported by a cartridge body together with a vibrator through a damper material, an electrorheological fluid (ER fluid) whose viscosity changes with applied voltage is used as the damper material.

JP, 2010-157299, A

  However, even if the technique described in Patent Document 1 is used, there is no change in the basic structure using the conventional pickup method, there is a limit to the degree of sound quality improvement, and there is a problem that further sound quality improvement is difficult.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to improve the sound quality in reproducing an analog record.

  One aspect of the pickup cartridge of the present invention is provided with a cartridge base member attached to a tone arm, and a surface of the cartridge base member facing the analog record in a state where the cartridge base member is attached to the tone arm. A pickup element for picking up, wherein the cartridge base member has a sound conduit for transmitting the vibration picked up by the pickup element, and a first opening provided on the side of the sound conduit on which the pickup element is provided. An elastic member that closes and supports the pickup element and transmits the vibration picked up by the pickup element to the sound conduit, and a second elastic member that is provided opposite to a side of the sound conduit where the pickup element is provided. And a microphone provided so as to close the opening.

  Since the pickup cartridge according to the present invention converts the vibration picked up by the stylus into an electric signal by the microphone, the vibration can be converted into an electric signal regardless of the vibration of the tone arm.

  The pickup cartridge of the present invention can improve the sound quality in reproducing an analog record.

FIG. 3 is a diagram illustrating an appearance of the pickup cartridge according to the first embodiment. FIG. 3 is a diagram illustrating a structure of a mounting portion of a pickup element of the pickup cartridge according to the first exemplary embodiment. FIG. 3 is a sectional view of the pickup cartridge according to the first exemplary embodiment. FIG. 3 is a diagram illustrating the relationship between the sound conduit and the microphone of the pickup cartridge according to the first embodiment. FIG. 3 is a diagram illustrating a sound vibration transmission direction when sound vibration is picked up from a record in the pickup cartridge according to the first exemplary embodiment. FIG. 6 is a diagram illustrating allocation of terminals of the cartridge according to the first exemplary embodiment. FIG. 3 is a diagram illustrating a latter stage circuit of the pickup cartridge according to the first exemplary embodiment.

Embodiment 1
Hereinafter, embodiments of the present invention will be described with reference to the drawings. For clarity of explanation, the following description and drawings are appropriately omitted and simplified. In each of the drawings, the same reference numerals are given to the same elements, and duplicate description is omitted as necessary.

  First, FIG. 1 is a diagram for explaining the external appearance of the pickup cartridge 1 according to the first embodiment. As shown in FIG. 1, in the pickup cartridge 1 according to the first embodiment, a terminal support member 11, a pickup element 12, an elastic member 13, a microphone 14, a wire 15, and a cartridge terminal 16 are attached to a cartridge base member 10. Further, the cartridge base member 10 is attached to a tone arm (not shown) provided on a turntable that rotates an analog record. In FIG. 1, since the pickup cartridge 1 is viewed from the right side surface direction, one microphone 14 and two wirings 15 and two cartridge terminals 16 are shown, but the microphone 14, wiring 15, and cartridge terminal 16 are Also provided on the left side surface, the pickup cartridge 1 has two microphones 14, four wires 15, and four cartridge terminals 16.

  The terminal support member 11 is, for example, an insulating member such as a resin member, and supports the cartridge terminal 16. Further, the cartridge terminal 16 is connected to the wiring 15 and constitutes a part of a signal transmission path to the subsequent circuit.

  In the turntable to which the pickup cartridge 1 according to the first embodiment is attached, the tone arm has a main function of supporting the pickup cartridge 1. On the other hand, in the pickup cartridge 1 according to the first embodiment, the sound vibration that is picked up from the analog record by the pickup element 12 is converted into an electric signal by the microphone 14 and the conversion circuit provided in the subsequent stage by using the wiring 15 and the cartridge terminal 16. Reproduce with an electric signal processing circuit such as an amplifier. Here, as the microphone 14, for example, a microphone that converts a minute amount of displacement of the sound receiving surface into an electric signal is preferable. In addition, the electric signal processing circuit provided at the subsequent stage of the pickup cartridge 1 may include a microphone amplifier that amplifies the audio signal from the microphone 14. A piezoelectric element may be used as a sensor instead of the microphone 14.

  Therefore, the detailed configuration of the pickup cartridge 1 according to the first embodiment will be described below. As shown in FIG. 1, in the pickup cartridge 1 according to the first embodiment, the pickup element 12 is provided on the surface facing the analog record with the cartridge base member 10 attached to the cartridge member. Then, the pickup element 12 picks up the vibration from the analog record.

  Therefore, the support mechanism of the pickup element 12 in the pickup cartridge 1 according to the first embodiment will be described with reference to FIG. FIG. 2 is a diagram for explaining the structure of the mounting portion of the pickup element 12 of the pickup cartridge according to the first embodiment.

  As shown in FIG. 2, the pickup element 12 has a stylus 21, a cantilever 22, and a ground end 23. The stylus 21 is a portion that is provided at the end of the pickup element 12 on the side that contacts the analog record and that contacts the unevenness engraved in the sound groove of the record. The grounding end 23 is an end on the side opposite to the stylus 21 on the side in contact with the analog record. Then, a rod-shaped member that connects the stylus 21 and the grounding end 23 becomes the cantilever 22. The pickup element 12 is attached to the cartridge base member 10 so as to be inserted into a pickup support member 24 supported by the elastic member 13. That is, the pickup support member 24 is a member formed of a cylindrical resin, and the pickup element 12 is inserted into the central cavity. In the completed state, the pickup element 12 is bonded to the pickup support member 24 and integrally molded. Also, as described in detail above, the pickup cartridge 1 is a pickup cartridge compatible with stereo reproduction, and the pickup support member 24 is provided to prevent interference of sound and vibration of the left and right channels.

  Further, as shown in FIG. 2, the cartridge base member 10 has a ground support portion 31. The ground support portion 31 supports the ground end 23 of the pickup element 12. The elastic member 13 supports the portion of the pickup element 12 between the stylus 21 and the ground end 23 (for example, the cantilever 22) via the pickup support member 24. As a result, the pickup element 12 vibrates with the ground end 23 in contact with the ground support portion 31 as the center point.

  In the pickup cartridge 1 according to the first embodiment, the vibration of the pickup element 12 is guided by the elastic member 13 to the sound conduit provided in the cartridge base member 10, and the vibration transmitted through the sound conduit is converted into an electric signal by the microphone 14. Convert. Therefore, the structure of the sound conduit of the pickup cartridge 1 according to the first embodiment will be described with reference to FIG.

  FIG. 3 is a sectional view of the pickup cartridge according to the first embodiment taken along the line III-III shown in FIG. As shown in FIG. 3, in the pickup cartridge 1 according to the first embodiment, when the cartridge base member 10 is viewed from the protruding direction of the stylus 12, two sounds are placed at positions symmetrical with respect to the support point of the stylus 12. A conduit (sound conduits 41a, 41b in FIG. 3) and two microphones (microphones 14a, 14b in FIG. 3) are provided. The position and angle are adjusted so that the center line of the sound conduit 41 a in the extending direction of the cylinder and the center line of the sound conduit 41 b in the extending direction of the cylinder intersect at the center point of the cantilever 22. Further, the angle θ between the horizontal line passing through the center point of the cantilever 22 and the tube center line of the sound conduit 41a and the angle θ between the horizontal line passing through the center point of the cantilever 22 and the tube center line of the sound conduit 41b are both 45 °. Is set to. The angle and position of the sound conduit are positional relationships required to guide the vibration of the unevenness engraved in the sound groove of the record to the microphones 14a and 14b provided on the left and right of the cantilever 22. In addition, in the example shown in FIG. 3, two sets of the sound conduit and the microphone are shown, but when monaural reproduction is performed, the configuration may be only one set.

  The sound conduits 41a and 41b have a cylindrical structure that transmits the vibration picked up by the pickup element 12. Further, as shown in FIG. 3, the elastic member 13 closes the first opening provided on the side of the sound conduits 41a and 41b on which the pickup element 12 is provided, and supports the pickup element 12 to support the stylus. The picked up vibration is transmitted to the sound conduits 41a and 41b.

  Further, the microphone 14a is provided so as to close the second opening provided on the opposite side of the sound conduit 41a to the side on which the stylus 12 is provided. The microphone 14b is provided so as to close the second opening provided on the opposite side of the sound conduit 41b to the side on which the stylus 12 is provided.

  Here, the elastic member 13 needs to have elasticity in order to guide the vibration of the stylus 12 to the sound conduits 41a and 41b, but its rigidity needs to have a predetermined hardness. As the elastic member 13, for example, a resin having a predetermined hardness such as silicon rubber is suitable.

  Further, as shown in FIG. 3, the pickup support member 24 is supported by the elastic member 13 and also supports the pickup element. In addition, the pickup support member 24 has a surface perpendicular to the center line in the extending direction of the cylinder of the sound conduit 41. The sound conduit 41 and the microphone 14 are symmetrical so that the center line of the extending direction of the cylinder of the sound conduit 41 intersects at the center point of the pickup element when the cartridge base member 10 is viewed from the protruding direction of the pickup element. Two are provided at the position.

  Further, since there is one characteristic in the relationship between the size of the second opening of the sound conduit and the sound receiving surface of the microphone, referring to FIG. 4, the area of the second opening of the sound conduit and the sound receiving surface are described. The relationship with the surface area will be described. FIG. 4 is a diagram for explaining the relationship between the sound conduit and the microphone of the pickup cartridge according to the first embodiment. Since the sound conduits 41a and 41b have the same structure and the microphones 14a and 14b also have the same structure, the reference numeral 41 is assigned to the sound conduit, and the reference numeral 14 is assigned to the microphone. Only one structure is shown.

  As shown in FIG. 4, in the pickup cartridge 1 according to the first embodiment, when the area of the sound receiving surface of the microphone 14 is S1 and the area of the second opening of the sound conduit 41 is S2, S1> S2. The area of the second opening of the sound conduit 41 is determined so that

  Further, as shown in FIG. 4, the sound conduit 41 is set so that the area of the second opening and the area of the first opening are substantially the same. That is, the sound conduit 41 has a tubular shape with the same thickness. The area of the second opening can also be considered as the thinnest portion of the sound conduit 41. For example, when the sound conduit 41 has a shape in which the diameter of the intermediate portion is narrowed, the area of the second opening can be considered as the cross-sectional area of the pipe in the narrowed portion.

  Further, as shown in FIGS. 3 and 4, in the pickup cartridge 1 according to the first embodiment, the sound conduit 41 is sealed by the microphone 14 and the elastic member 13.

  Here, a method of transmitting sound vibration when performing record reproduction using the pickup cartridge 1 according to the first embodiment, and a method of transmitting an electric signal generated from the sound vibration will be described. Therefore, FIG. 5 shows a diagram for explaining a sound vibration transmission direction when sound vibration is picked up from a record in the pickup cartridge 1 according to the first exemplary embodiment.

  As shown in FIG. 5, in the stereo compatible record, the right wall and the left wall of the sound groove are provided with an angle of 45 °. Then, in the sound groove, unevenness corresponding to the right channel is engraved on the right wall, and unevenness corresponding to the left channel is engraved on the left wall. The stylus 21 transmits to the cantilever 22 vibrations according to the unevenness engraved in the sound groove when tracing the sound groove. The sound transmitted to the cantilever 22 has an angle of 45 ° from the center line of the cantilever 22 passing through the center point of the cantilever 22 and is distributed to the left and right in a direction along a straight line intersecting with the center point of the cantilever 22. To be done. Specifically, the sound of the right channel is transmitted diagonally upward to the left of the cantilever 22, and is transmitted to the microphone 14a via the sound conduit 41a shown in FIG. Further, the sound of the left channel is transmitted diagonally to the right above the cantilever 22 and is transmitted to the microphone 14b via the sound conduit 41b shown in FIG.

  Here, in the electric signal output from the pickup cartridge 1 according to the first embodiment, one of the sounds of the left and right channels becomes a reverse phase signal. Therefore, the signal that is out of phase is inverted using a conversion circuit and then input to the microphone amplifier. Therefore, first, the cartridge terminal 16 provided in the pickup cartridge 1 will be described. FIG. 6 is a diagram illustrating allocation of the terminals 16 of the cartridge according to the first embodiment.

  As shown in FIG. 6, the pickup cartridge 1 according to the first embodiment has, as the cartridge terminals 16, a left channel positive electrode terminal T1, a right channel positive electrode terminal T2, a negative electrode terminal T3, and a microphone power supply terminal T4. The left channel positive terminal T1 is a terminal for extracting the left channel sound signal output from the microphone 14b. The right channel positive terminal T2 is a terminal for taking out the right channel sound signal output from the microphone 14a. The negative electrode terminal T3 is a ground potential supply terminal commonly applied to the microphones 14a and 14b. The microphone power supply terminal T4 is a microphone power supply terminal commonly provided to the microphones 14a and 14b.

  In the pickup cartridge 1 according to the first embodiment, cables are connected to these terminals, and signals or power are exchanged between the pickup cartridge 1 and a subsequent circuit. Therefore, FIG. 7 shows a diagram for explaining the latter stage circuit of the pickup cartridge according to the first embodiment. The latter circuit is also a circuit that performs signal processing of the sound signals output from the microphones 14a and 14b and supplies power to the microphones 14a and 14b.

  As shown in FIG. 7, a conversion circuit and a microphone amplifier are connected to the rear stage of the pickup cartridge 1 as a rear stage circuit. Although illustration is omitted, a power amplifier, a speaker, and the like are connected to the subsequent stage of the microphone amplifier. As will be described later in detail, in the pickup cartridge 1 according to the first embodiment, since sound vibration is transmitted by the fluid, sound quality can be obtained without using an equalizer. However, the equalizer is provided before the power amplifier. You may arrange.

  In the pickup cartridge 1 according to the first embodiment, the sound signal output from one of the left and right channels is an opposite phase signal. Therefore, a conversion circuit is provided between the pickup cartridge 1 and the microphone amplifier, and the conversion circuit performs conversion so that the left and right channel signals become positive phase signals. Therefore, FIG. 7 shows a circuit diagram of the conversion circuit. In the example shown in FIG. 7, since the right channel sound signal is a reverse phase signal, the conversion circuit inverts the phase of the right channel sound signal.

  The conversion circuit has resistors R1 to R6 and capacitors C1 to C4. The resistors R1, R3, R4, R6 are resistors having a resistance value of about 50 kΩ, for example. The resistors R2 and R5 are resistors having a resistance value of about 2 kΩ, for example. The capacitors C1 to C4 are capacitors having a capacitance value of about 2.2 μF. Note that the resistance value and the capacitance value described above are examples, and may be various values depending on the specifications.

  The left channel sound signal output from the left channel positive terminal T1 is input from the terminal Lch + and becomes the left channel positive input signal of the microphone amplifier via the capacitor C1. This left channel positive polarity input signal is output from the terminal Lin +. A resistor R1 is provided between the wiring between the capacitor C1 and the terminal Lin + and the microphone power supply output terminal MicPWR connected to the microphone power supply terminal T4. Further, the phantom power supply P_PWR is supplied to the wiring between the capacitor C1 and the terminal Lin +.

  The ground potential applied to the negative electrode terminal T3 is input from two terminals of the ground terminal Lgnd for the left channel and the ground terminal Rgnd for the right channel, and output from the common ground terminal CM-. A resistor R2 is provided between the wiring connecting the ground terminal Lgnd for the left channel and the common ground terminal CM− and the microphone power supply output terminal MicPWR. A resistor R5 is provided between the wiring connecting the ground terminal Rgnd for the right channel and the common ground terminal CM− and the microphone power supply output terminal MicPWR.

  Further, the wiring that connects the ground terminal Lgnd for the left channel and the common ground terminal CM- is branched midway, and between the branch point and the terminal Lin- that is the output terminal of the left channel negative input signal, A capacitor C2 is provided. A resistor R3 is provided between the line connecting the capacitor C2 and the terminal Lin− and the microphone power output terminal MicPWR. Further, the phantom power supply P_PWR is supplied to the wiring between the capacitor C1 and the terminal Lin−.

  In addition, the wiring that connects the ground terminal Rgnd for the right channel and the common ground terminal CM- is branched midway, and a capacitor is provided between the branch point and the terminal Rin + that is the output terminal of the right channel positive input signal. C3 is provided. A resistor R6 is provided between the line connecting the capacitor C3 and the terminal Rin− and the microphone power output terminal MicPWR. The phantom power supply P_PWR is supplied to the wiring between the capacitor C3 and the terminal Rin +.

  The right channel sound signal output from the right channel positive terminal T2 is input from the terminal Rch + and becomes a right channel negative input signal of the microphone amplifier via the capacitor C4. This right channel negative input signal is output from the terminal Rin-. A resistor R4 is provided between the wiring between the capacitor C4 and the terminal Rin− and the microphone power output terminal MicPWR. The phantom power supply P_PWR is supplied to the wiring between the capacitor C4 and the terminal Rin-.

  From the above description, the pickup cartridge 1 according to the first embodiment transmits the vibration picked up by the pickup element 12 from the analog record to the microphone 14 via the sound conduit 41 sealed by the elastic member 13 and the microphone 14. As a result, in the pickup cartridge 1 according to the first embodiment, the vibration of the pickup element 12 is transmitted to the microphone 14 without superimposing the noise caused by the weight of the tone arm and the pickup cartridge and other vibrations, and the electric signal is transmitted. Is converted to. That is, in the pickup cartridge 1 according to the first embodiment, by using the microphone 14 as the power generation element, it is not affected by the natural vibration of the power generation element, so that the damper can be simplified and the frequency characteristic can be improved. it can.

  With the pickup cartridge 1 according to the first embodiment, by virtue of such a configuration, by converting vibration into an electric signal, rising of a low tone, break of a high tone, high resolution sound, and the like, which is difficult to realize with other pickup cartridges. A sound signal with high sound quality can be obtained. It has been verified by experiments by the inventors that such characteristics can be improved to the extent that they can be clearly recognized in the sense of hearing, although it is difficult to analyze the frequency characteristics of the audio signal taken out from the pickup cartridge.

  In the pickup cartridge 1 according to the first embodiment, it is not necessary to house a coil or a magnet in the magnetic gap as a power generation element, and structural restrictions are reduced, so that the tracing ability of the stylus 22 can be enhanced.

  Further, in the pickup cartridge 1 according to the first embodiment, a condenser microphone is used as the microphone 14. By using the condenser microphone in this manner, the sound signal output from the pickup cartridge 1 has an amplitude proportional characteristic. Here, the amplitude proportional pickup cartridge is generally subjected to equalizing processing of about ± 20 dB in the subsequent circuit, and the speed proportional pickup cartridge is subjected to equalizing processing of about ± 39 dB. However, in the pickup cartridge 1 according to the first embodiment, it is possible to obtain an equalizing effect by the fluid in the pickup cartridge. Therefore, when the pickup cartridge 1 according to the first embodiment is used, it has been confirmed by verification that there is no problem even if the sound signal output from the pickup cartridge 1 is input to the power amplifier without performing the equalizing process. It was As described above, by omitting the equalizing process, the sound system using the pickup cartridge 1 according to the first embodiment can realize a higher sound quality.

  Further, in the pickup cartridge 1 according to the first embodiment, the sound conduit 41 has a closed structure. As a result, in the pickup cartridge 1 according to the first embodiment, the vibration is transmitted to the microphone 14 using air (that is, fluid). By performing the vibration using such a fluid, the efficiency of impedance matching can be improved, and the amplitude of the output voltage is about 30% higher than the output voltage amplitude output from other amplitude proportional pickup cartridges. can do. By obtaining such a large output voltage amplitude, it is possible to reduce the dependence on the amplifier provided in the subsequent stage and realize a natural reproduced sound. Even if a fluid such as air is used to transmit vibration, a peak appears in the frequency characteristic, but the peak can be removed from the human audible range by adjusting the length of the sound conduit 41.

  Further, in the pickup cartridge 1 according to the first embodiment, the area of the second opening provided on the microphone side of the sound conduit 41 is set smaller than the area of the sound receiving surface of the microphone 14. Thereby, in the pickup cartridge 1, the vibration transmitted to the microphone 14 can be pseudo-amplified, the vibration detection accuracy in the microphone 14 can be improved, and the output signal amplitude can be increased.

  Further, in the pickup cartridge 1 according to the first embodiment, two sets of the sound conduit and the microphone are provided so as to be symmetrical with respect to the support point of the pickup element 12. As a result, the pickup cartridge 1 according to the first embodiment enables stereo reproduction.

  The present invention is not limited to the above-mentioned embodiments, but can be modified as appropriate without departing from the spirit of the present invention.

1 Pickup Cartridge 10 Cartridge Base Member 11 Terminal Support Member 12 Pickup Element 13 Elastic Member 14 Microphone 15 Wiring 16 Cartridge Terminal 21 Stylus 22 Cantilever 23 Grounding End 24 Pickup Supporting Member 31 Grounding Support 41 Sound Channel T1 Left Channel Positive Terminal T2 Right Channel Positive terminal T3 Negative terminal T4 Microphone power terminal

Claims (5)

A cartridge base member attached to the tone arm,
A pickup element that is provided on a surface facing the analog record in a state where the cartridge base member is attached to the tone arm, and that picks up vibration from the analog record,
The cartridge base member,
A sound conduit for transmitting the vibration picked up by the pickup element;
An elastic member that closes the first opening provided on the side of the sound conduit on which the pickup element is provided, and that supports the pickup element and transmits the vibration picked up by the pickup element to the sound conduit.
A pickup cartridge having a microphone provided so as to close a second opening provided on the opposite side of the sound conduit from the side provided with the pickup element.   The pickup cartridge according to claim 1, wherein an area of the second opening of the sound conduit is smaller than an area of a sound receiving surface of the microphone.   The pickup cartridge according to claim 1, wherein the microphone is a condenser microphone. Further comprising a pickup support member supported by the elastic member and supporting the pickup element, the pickup support member having a surface perpendicular to the center line of the extending direction of the cylinder of the sound conduit,
The sound conduit and the microphone are symmetrically positioned so that the center line of the extending direction of the sound conduit intersects at the center point of the pickup element when the cartridge base member is viewed from the protruding direction of the pickup element. The pickup cartridge according to claim 1, wherein two pickup cartridges are provided. The cartridge base member is
Of the pickup element, a stylus on the side in contact with the analog record has a ground end supporting portion for supporting a ground end provided at an end opposite to the stylus,
The elastic member supports a portion of the pickup element between the stylus and the ground end,
The pickup cartridge according to any one of claims 1 to 4, wherein the pickup element vibrates with the ground end in contact with the ground end support portion as a center point.

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