阅读说明：本技术 一种动圈唱头放大电路 (Moving coil phonograph head amplifying circuit ) 是由 温上凯 于 2021-08-05 设计创作，主要内容包括：本发明公开了一种动圈唱头放大电路,其包括：匹配网络,所述匹配网络与信号输入端电连接；低频响应滤波电路,所述低频响应滤波电路对称设置并分别电连接正、负电源,所述低频响应滤波电路与所述匹配网络电连接；静态工作点电路,所述静态工作点电路与所述低频响应滤波电路、所述匹配网络电连接,所述静态工作点电路对称设置并分别电连接正、负电源；放大单元,所述放大单元包括：第一晶体管和第二晶体管,所述放大单元与所述匹配网络、所述低频响应滤波电路、所述静态工作点电路、信号输入端、信号输出端电连接；输出端负载,所述输出端负载与所述放大单元、信号输出端电连接；实现了低噪声、低失真、高信噪比、高动态范围、宽频率响应的特点。(The invention discloses a moving coil and gramophone head amplifying circuit, which comprises: the matching network is electrically connected with the signal input end; the low-frequency response filter circuit is symmetrically arranged and is respectively and electrically connected with the positive power supply and the negative power supply, and the low-frequency response filter circuit is electrically connected with the matching network; the static working point circuit is electrically connected with the low-frequency response filter circuit and the matching network, and is symmetrically arranged and respectively and electrically connected with a positive power supply and a negative power supply; an amplification unit, the amplification unit comprising: the amplifying unit is electrically connected with the matching network, the low-frequency response filter circuit, the static operating point circuit, the signal input end and the signal output end; the output end load is electrically connected with the amplifying unit and the signal output end; the characteristics of low noise, low distortion, high signal-to-noise ratio, high dynamic range and wide frequency response are realized.)

1. A moving coil cartridge amplifying circuit, comprising: a matching network using paired complementary transistor pairs, the matching network being electrically connected to the signal input;

the low-frequency response filter circuit is used for determining the low-frequency response and filtering of the circuit, the low-frequency response filter circuit is symmetrically arranged and is respectively and electrically connected with a positive power supply and a negative power supply, and the low-frequency response filter circuit is electrically connected with the matching network;

the static working point circuit is used for determining a static working point of the circuit, the static working point circuit is electrically connected with the low-frequency response filter circuit and the matching network, and the static working point circuit is symmetrically arranged and is respectively and electrically connected with a positive power supply and a negative power supply;

an amplification unit, the amplification unit comprising: the first transistor is used for amplifying a positive half period of an input signal, the second transistor is used for amplifying a negative half period of the input signal, the first transistor and the second transistor form a complementary amplifying circuit, and the amplifying unit is electrically connected with the matching network, the low-frequency response filter circuit, the static operating point circuit, a signal input end and a signal output end;

and the output end load is electrically connected with the amplifying unit and the signal output end.

2. The moving coil cartridge amplifying circuit as claimed in claim 1, wherein said output terminal load is a tenth resistor, said tenth resistor being electrically connected to the signal output terminal, the collectors of said first and second transistors and grounded.

3. The moving coil cartridge amplifying circuit as claimed in claim 1, wherein said matching network comprises: the circuit comprises a first resistor, a first capacitor and a second capacitor, wherein the first resistor is a matched resistor, and the input end of the first resistor is electrically connected with a signal input end, the input end of the first capacitor, the input end of the second capacitor, the base electrode of the first transistor and the base electrode of the second transistor;

the first capacitor and the second capacitor are symmetrically arranged and are high-frequency compensation capacitors and matching capacitors, the output end of the first capacitor is electrically connected with the emitter of the first transistor, and the output end of the second capacitor is electrically connected with the emitter of the second transistor.

4. The moving coil cartridge amplifying circuit as claimed in claim 1, wherein said low frequency response filter circuit comprises: a positive half-cycle unit and a negative half-cycle unit;

the positive half cycle unit includes: the negative electrode of the third capacitor is grounded, the positive electrode of the third capacitor is electrically connected with the matching network, the first end of the eighth resistor and the emitter of the first transistor, and the second end of the eighth resistor is electrically connected with a positive power supply;

the negative half cycle unit includes: the positive electrode of the fourth capacitor is grounded, the negative electrode of the fourth capacitor is electrically connected with the matching network, the first end of the ninth resistor and the emitter of the second transistor, and the second end of the ninth resistor is electrically connected with a negative power supply.

5. The moving coil cartridge amplifying circuit as claimed in claim 4, wherein said static operating point circuit comprises: a positive half cycle static operating point unit and a negative half cycle static operating point unit;

the positive half-cycle static operating point unit comprises: the input end of the sixth resistor is electrically connected with the matching network, and the output end of the sixth resistor is electrically connected with the first end of the eighth resistor;

the negative half cycle static operating point unit comprises: the input end of the seventh resistor is electrically connected with the matching network, and the output end of the seventh resistor is electrically connected with the first end of the ninth resistor.

6. The moving coil cartridge amplifying circuit as claimed in claim 1, wherein said first transistor is PNP type, said second transistor is NPN type, and collectors of said first transistor and said second transistor are connected together.

7. The moving-coil-pickup amplifying circuit as claimed in claim 1, wherein said matching network is provided with a matching resistor, and a pairing detection method of said first transistor and said second transistor: and detecting the voltage at two ends of the matching resistor, wherein if the voltage at two ends of the matching resistor is floating, the first transistor and the second transistor are not well paired, otherwise, the first transistor and the second transistor are well paired.

8. The moving coil cartridge amplifying circuit as claimed in claim 1, wherein said first transistor and said second transistor are collector loads of each other.

9. The moving coil cartridge amplifying circuit as claimed in claim 5, wherein the circuit output dc offset adjusting step comprises:

s010, the first transistor and the second transistor are well matched, and the resistance values of an eighth resistor and a ninth resistor are determined;

and S020, adjusting the output direct current offset of the circuit by adjusting the resistance values of the sixth resistor and the seventh resistor.

Technical Field

The invention relates to the technical field of amplifying circuits, in particular to a moving coil and gramophone head amplifying circuit.

Background

In order to obtain better output effect, the existing MC record player amplifier circuit, for example: low noise, low distortion, high signal-to-noise ratio, etc. Generally, a plurality of modules or circuits are integrated together to improve the output effect, so that the whole circuit architecture is too complex, and the debugging is complicated and time-consuming.

Meanwhile, the existing MC record player amplifier circuit often has a dc voltage at its input end, which causes an increase in dc offset and circuit distortion of the circuit, and thus fails to achieve a better output effect. The compatibility effect of the external module and the circuit is poor, and the adjustment and the design are often required to be carried out again.

Accordingly, there is a need for a moving-coil phonograph amplifier circuit that addresses one or more of the above problems.

Disclosure of Invention

To address one or more of the problems of the prior art, the present invention provides a moving coil cartridge amplifying circuit. The technical scheme adopted by the invention for solving the problems is as follows: a moving-coil-pickup amplifying circuit comprising: a matching network for pairing complementary transistor pairs, the matching network being electrically connected to the signal input; the low-frequency response filter circuit is used for determining the low-frequency response and filtering of the circuit, the low-frequency response filter circuit is symmetrically arranged and is respectively and electrically connected with a positive power supply and a negative power supply, and the low-frequency response filter circuit is electrically connected with the matching network; the static working point circuit is used for determining a static working point of the circuit, the static working point circuit is electrically connected with the low-frequency response filter circuit and the matching network, and the static working point circuit is symmetrically arranged and is respectively and electrically connected with a positive power supply and a negative power supply; an amplification unit, the amplification unit comprising: the first transistor is used for amplifying a positive half period of an input signal, the second transistor is used for amplifying a negative half period of the input signal, the first transistor and the second transistor form a complementary amplifying circuit, and the amplifying unit is electrically connected with the matching network, the low-frequency response filter circuit, the static operating point circuit, a signal input end and a signal output end; and the output end load is electrically connected with the amplifying unit and the signal output end.

Furthermore, the output end load is a tenth resistor, and the tenth resistor is electrically connected with the signal output end and the collectors of the first transistor and the second transistor and grounded.

Further, the matching network comprises: the circuit comprises a first resistor, a first capacitor and a second capacitor, wherein the first resistor is a matched resistor, and the input end of the first resistor is electrically connected with a signal input end, the input end of the first capacitor, the input end of the second capacitor, the base electrode of the first transistor and the base electrode of the second transistor;

the first capacitor and the second capacitor are symmetrically arranged and are high-frequency compensation capacitors and matching capacitors, the output end of the first capacitor is electrically connected with the emitter of the first transistor, and the output end of the second capacitor is electrically connected with the emitter of the second transistor.

Further, the low frequency response filter circuit includes: a positive half-cycle unit and a negative half-cycle unit; the positive half cycle unit includes: the negative electrode of the third capacitor is grounded, the positive electrode of the third capacitor is electrically connected with the matching network, the first end of the eighth resistor and the emitter of the first transistor, and the second end of the eighth resistor is electrically connected with a positive power supply; the negative half cycle unit includes: the positive electrode of the fourth capacitor is grounded, the negative electrode of the fourth capacitor is electrically connected with the matching network, the first end of the ninth resistor and the emitter of the second transistor, and the second end of the ninth resistor is electrically connected with a negative power supply.

Further, the static operating point circuit includes: a positive half cycle static operating point unit and a negative half cycle static operating point unit; the positive half-cycle static operating point unit comprises: the input end of the sixth resistor is electrically connected with the matching network, and the output end of the sixth resistor is electrically connected with the first end of the eighth resistor; the negative half cycle static operating point unit comprises: the input end of the seventh resistor is electrically connected with the matching network, and the output end of the seventh resistor is electrically connected with the first end of the ninth resistor.

Further, the first transistor is a PNP type, the second transistor is an NPN type, and collectors of the first transistor and the second transistor are connected together.

Further, the matching network is provided with a matching resistor, and the pairing detection method of the first transistor and the second transistor comprises the following steps: and detecting the voltage at two ends of the matching resistor, wherein if the voltage at two ends of the matching resistor is floating, the first transistor and the second transistor are not well paired, otherwise, the first transistor and the second transistor are well paired.

Further, the first transistor and the second transistor are collector loads of each other.

Further, the step of adjusting the output dc offset of the circuit comprises:

s010, the first transistor and the second transistor are well matched, and the resistance values of an eighth resistor and a ninth resistor are determined;

and S020, adjusting the output direct current offset of the circuit by adjusting the resistance values of the sixth resistor and the seventh resistor.

The invention has the following beneficial values: according to the invention, the matching network, the low-frequency response filter circuit, the static working point circuit, the amplifying unit and other circuits are connected together through a smart design, so that partial components are shared by all the circuits on the premise of ensuring the normal function of the circuits, thereby reducing the overall volume of the circuit and reducing the power consumption; the characteristics of low noise, low distortion, high signal-to-noise ratio, high dynamic range, wide frequency response and the like are realized, and meanwhile, due to the simplification of the circuit, the debugging of the circuit is easier; in the debugging process of the circuit, the transistors can be conveniently paired, the pairing accuracy of the transistors is improved, and the output direct current offset of the circuit is reduced by finely adjusting the sixth resistor and the seventh resistor. The practical value of the invention is greatly improved.

Drawings

Fig. 1 is a schematic diagram of a moving coil cartridge amplifying circuit according to the present invention;

FIG. 2 is a schematic block diagram of a moving coil pickup amplifying circuit according to the present invention;

FIG. 3 is a waveform of a small signal output when an embodiment of a moving-coil-pickup amplifying circuit according to the present invention is implemented;

FIG. 4 is a graph of a large signal output waveform for an implementation of a moving coil pickup amplifying circuit according to the present invention;

FIG. 5 is a frequency response curve of a moving coil pickup amplifying circuit according to the present invention;

fig. 6 is a fundamental zero to nine harmonic distortion rate table of a moving-coil-pickup amplifying circuit of the present invention.

[ reference numerals ]

101. matching network

201 positive half cycle unit of low frequency response filter circuit

301. first transistor circuit of an amplifying cell

401. second transistor circuit of amplification unit

501 negative half-cycle unit of low-frequency response filter circuit

601. output end load.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

As shown in fig. 1 to 2, the present invention discloses a moving-coil cartridge amplifying circuit, which includes: the matching network is used for matching the output impedance of the complementary transistor pair and the MC record player and is electrically connected with the signal input end;

the low-frequency response filter circuit is used for determining the low-frequency response and filtering of the circuit, the low-frequency response filter circuit is symmetrically arranged and is respectively and electrically connected with a positive power supply (VCC) and a negative power supply (VEE), and the low-frequency response filter circuit is electrically connected with the matching network;

the static working point circuit is used for determining a static working point of the circuit, the static working point circuit is electrically connected with the low-frequency response filter circuit and the matching network, and the static working point circuit is symmetrically arranged and is respectively and electrically connected with a positive power supply (VCC) and a negative power supply (VEE);

an amplification unit, the amplification unit comprising: a first transistor Q01 and a second transistor Q02, the first transistor Q01 is used for amplifying the positive half period of the input signal, the second transistor Q02 is used for amplifying the negative half period of the input signal, the first transistor Q01 and the second transistor Q02 form a complementary amplifying circuit, and the amplifying unit is electrically connected with the matching network, the low frequency response filter circuit, the static operating point circuit, the signal input end and the signal output end;

and the output end load is electrically connected with the amplifying unit and the signal output end.

Specifically, as shown in fig. 1, the output terminal load is a tenth resistor R10 (load resistor), a first end of the tenth resistor R10 is electrically connected to the signal output terminal and the collectors of the first and second transistors (Q01 and Q02), and a second end of the tenth resistor R10 is grounded.

Specifically, as shown in fig. 1, the matching network includes: a first resistor R01, a first capacitor C01 and a second capacitor C02, wherein the first resistor R01 is a matching resistor, and an input end of the first resistor R01 is electrically connected with a signal input end, an input end of the first capacitor C01, an input end of the second capacitor C02, a base of the first transistor Q01 and a base of the second transistor Q02; the first capacitor C01 and the second capacitor C02 are symmetrically arranged and are high-frequency compensation capacitors and matching capacitors, an output end of the first capacitor C01 is electrically connected with an emitter of the first transistor Q01, and an output end of the second capacitor C02 is electrically connected with an emitter of the second transistor Q02.

The low frequency response filter circuit includes: a positive half-cycle unit and a negative half-cycle unit;

the positive half cycle unit includes: a third capacitor C03 and an eighth resistor R08, wherein the cathode of the third capacitor C03 is grounded, the anode of the third capacitor C03 is electrically connected to the matching network, the first end of the eighth resistor R08 and the emitter of the first transistor Q01, and the second end of the eighth resistor R08 is electrically connected to a positive power source VCC;

the negative half cycle unit includes: a fourth capacitor C04 and a ninth resistor R09, wherein the anode of the fourth capacitor C04 is grounded, the cathode of the fourth capacitor C04 is electrically connected to the matching network, the first end of the ninth resistor R09 and the emitter of the second transistor Q02, and the second end of the ninth resistor R09 is electrically connected to a negative power supply VEE;

the low-frequency response filter circuit forms a filter circuit of positive and negative power supplies through the third capacitor C03, the eighth resistor R08, the fourth capacitor C04 and the ninth resistor R09, and simultaneously determines the low-frequency response of the circuit.

The static operating point circuit includes: a positive half cycle static operating point unit and a negative half cycle static operating point unit;

the positive half-cycle static operating point unit comprises: a sixth resistor R06 and the eighth resistor R08, wherein an input terminal of the sixth resistor R06 is electrically connected to the matching network, and an output terminal of the sixth resistor R06 is electrically connected to a first terminal of the eighth resistor R08;

the negative half cycle static operating point unit comprises: a seventh resistor R07 and the ninth resistor R09, wherein the input terminal of the seventh resistor R07 is electrically connected to the matching network, and the output terminal of the seventh resistor R07 is electrically connected to the first terminal of the ninth resistor R09.

Specifically, the high frequency response of the circuit is mainly determined by the Cob (base collector capacitance) of the first transistor Q01 and the second transistor Q02, and the first capacitor C01 and the second capacitor C02. The gain of the circuit is mainly determined by the eighth resistor R08, the ninth resistor R09 and the tenth resistor R10, wherein the gain is mainly determined by the tenth resistor R10.

The positive electrode of the third capacitor C03 is electrically connected to the output terminal of the first capacitor C01 and the output terminal of the sixth resistor R06; the cathode of the fourth capacitor C04 is electrically connected with the output end of the second capacitor C02 and the output end of the seventh resistor R07; the input end of the sixth resistor R06 is electrically connected with the input end of the first capacitor C01 and the signal input end; the input end of the seventh resistor R07 is electrically connected with the input end and the signal input end of the second capacitor C02.

Note that, as shown in fig. 1, the first transistor Q01 is of PNP type, the second transistor Q02 is of NPN type, and the collectors of the first transistor Q01 and the second transistor Q02 are connected together. The invention belongs to a pure A-type common collector complementary push-pull circuit, wherein an upper tube and a lower tube of a push-pull arm are mutually opposite collector loads.

Specifically, the pairing detection method of the first transistor Q01 and the second transistor Q02: detecting a voltage across the matching resistor R01, if the voltage across the matching resistor R01 is floating, the first transistor Q01 and the second transistor Q02 are not paired, otherwise the first transistor Q01 and the second transistor Q02 are paired; is not only at V_RO1When the value is 0, the first transistor Q01 and the second transistor Q02 are paired.

Specifically, the step of adjusting the output dc offset of the circuit includes:

s010, the first transistor Q01 and the second transistor Q02 are well matched, and the resistance values of an eighth resistor R08 and a ninth resistor R09 are determined;

and S020, adjusting the output direct current offset of the circuit by adjusting the resistance values of the sixth resistor R06 and the seventh resistor R07.

Fig. 5 is a frequency response curve of the present invention, and it can be seen from the observation that the present invention can achieve a good frequency response effect (the response curve segment is flat) in the range of about 10Hz to about 1MHz, and it can be seen that the frequency response range of the present invention for normal operation is 10Hz to 1 MHz. Fig. 5, in conjunction with the harmonic comparison table shown in fig. 6, shows that the distortion rate of the amplified signal outputted by the present invention is very low within the frequency response range of the present invention.

Fig. 3 is a waveform diagram of a small signal outputted by the present invention, fig. 4 is a waveform diagram of a large signal outputted by the present invention, and fig. 6 is a distortion rate table (a comparison table of a standard output of harmonics and a harmonic outputted by the present invention) of the present invention, in which THD (total harmonic distortion) is 0.00207441% in fig. 6; as can be seen from fig. 3 and 4, the offset of the large signal and the small signal output by the present invention is extremely small, and a good low distortion effect and amplification effect can be obtained, thereby improving the user experience.

When the circuit is seen in fig. 3 and 4 in combination with fig. 1, the dynamic range of the circuit can reach 106dB from a small signal waveform to a large signal waveform, i.e. from 500nV for a small signal to 100mV for a large signal. The distortion rate is also small from the perspective that the harmonic distortion rate is only 0.00207441%. From the frequency response curve, the effective frequency response can reach 10Hz to 1MHz, and the frequency response is flat without large fluctuation (the fluctuation is within plus or minus 0.1 dB).

In conjunction with the description of fig. 3-6, it can be seen that the present invention can achieve good effects of low noise, low distortion, high signal-to-noise ratio, high dynamic range, and wide frequency response in the frequency range of 10Hz to 1 MHz.

As shown in fig. 2, after the input signal enters the matching network 101 (including input impedance and input capacitance) at the signal input end, the input signal of the positive half cycle enters the positive half cycle unit 201 (input signal positive half cycle amplifying circuit) of the low frequency response filter circuit, then enters the first transistor circuit 301 (input signal positive half cycle amplifying circuit active load) of the amplifying unit, and then is output at the output end load 601 (synthesis circuit); the input signal of the negative half cycle enters the negative half cycle unit 501 (the input signal negative half cycle amplifying circuit) of the low frequency response filter circuit, enters the second transistor circuit 401 (the input signal negative half cycle amplifying circuit active load) of the amplifying unit, and is output at the output end load 601 (the synthesizing circuit).

In summary, the matching network, the low-frequency response filter circuit, the static operating point circuit, the amplifying unit and other circuits are connected together through a smart design, so that partial components are shared by all the circuits on the premise of ensuring the normal function of the circuits, thereby reducing the overall volume of the circuits and reducing the power consumption; the characteristics of low noise, low distortion, high signal-to-noise ratio, high dynamic range, wide frequency response and the like are realized, and meanwhile, due to the simplification of the circuit, the debugging of the circuit is easier; in the debugging process of the circuit, the transistors can be conveniently paired, the pairing accuracy of the transistors is improved, and the output direct current offset of the circuit is reduced by finely adjusting the sixth resistor and the seventh resistor. The practical value of the invention is greatly improved.

The above-described examples merely represent one or more embodiments of the present invention, which are described in greater detail and detail, but are not to be construed as limiting the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the spirit of the invention, which falls within the scope of the invention. Therefore, the protection scope of the present invention should be subject to the appended claims.