CN108834026A - A kind of tone circuit for regulating and controlling based on NE5532 chip - Google Patents

Abstract

The invention discloses a tone control circuit based on NE5532 chip, which includes: a preamplifier circuit, the two input terminals of which are respectively used to access the left channel audio signal and the right channel audio signal, and the preamplifier circuit includes There are amplifier U1A and amplifier U1B, the amplifier U1A and the amplifier U1B are integrated in a NE5532 chip, the amplifier U1A and the amplifier U1B are respectively used to amplify the left channel audio signal and the right channel audio signal; a tone control circuit, the two The input terminals are respectively connected to the output terminals of the amplifier U1A and the amplifier U1B, and the tone control circuit is used to adjust the bass, midrange and treble of the two audio signals amplified by the amplifier U1A and the amplifier U1B respectively; Used to adjust the volume of two audio signals. The invention can better amplify, rectify, filter and fidelity process the sound, eliminate unnecessary interference at the same time, and obtain better sound quality.

Description

A tone control circuit based on NE5532 chip

technical field

The invention relates to an audio signal adjustment circuit, in particular to a tone adjustment circuit based on the NE5532 chip.

Background technique

Due to the limited space in modern family rooms, audio miniaturization is also a development direction of consumer audio products, and the timbre of small and medium speakers is prone to problems such as thin and delicate. Commercially available tone boards include finished speakers, most of which are sharp and harsh, especially the bass is blurred, not to mention the subwoofer, which cannot meet the requirements of ordinary home audio. In addition, most of the audio equipment on the market today needs tone boards to compensate for the fact that the preamplifiers and power amplifiers are not of the highest quality. However, most of the tone boards on the market, including finished audio, are sharp and piercing, and the bass is fuzzy, especially The subwoofer effect is poor and cannot meet the needs of consumers.

Existing audio signal conditioning circuits usually use multiple amplifiers and multiple filters, including a circulator, a switch limiter, a first power amplifier, an attenuator, a transceiver switch, a third power amplifier, a second filter, and a limiter , the second power amplifier, etc., which not only ensure the signal-to-noise ratio of the signal, but also ensure the gain of the signal, and provide a certain amount of power for subsequent signal analysis or signal transmission, but such circuits still have complex circuit structures and high costs. , poor sound quality and other issues, unable to meet user needs.

Contents of the invention

The technical problem to be solved by the present invention is to provide a NE5532-based audio system that can better amplify, rectify, filter, and fidelity process the sound while eliminating unnecessary interference to obtain better sound quality. The tone control circuit of the chip.

In order to solve the above technical problems, the present invention adopts the following technical solutions.

A tone control circuit based on the NE5532 chip, which includes: a preamplifier circuit, its two input terminals are respectively used to access the left channel audio signal and the right channel audio signal, and the preamplifier circuit includes an amplifier U1A and amplifier U1B, the amplifier U1A and the amplifier U1B are integrated in a NE5532 chip, the amplifier U1A and the amplifier U1B are respectively used to amplify the left channel audio signal and the right channel audio signal; a tone control circuit, Its two input terminals are respectively connected to the output terminals of the amplifier U1A and the amplifier U1B, and the tone control circuit is used to adjust the bass, midrange and treble of the two audio signals amplified by the amplifier U1A and the amplifier U1B respectively; The two input ends of the adjustment circuit are respectively connected to the two audio signal output ends of the tone control circuit, and the volume adjustment circuit is used to adjust the volume of the two audio signals.

Preferably, the non-inverting terminal of the amplifier U1A is grounded, the inverting terminal of the amplifier U1A is connected to the first terminal of the resistor R2, and a resistor R3 is connected between the output terminal of the amplifier U1A and the inverting terminal. The output terminal of U1A is connected to an input terminal of the tone control circuit through a resistor R4; the non-inverting terminal of the amplifier U1B is grounded, the inverting terminal of the amplifier U1B is connected to the first terminal of the resistor Re2, and the output terminal of the amplifier U1B A resistor Re3 is connected between the inverting terminal and the output terminal of the amplifier U1B is connected to the other output terminal of the tone control circuit through a resistor Re4; the second terminal of the resistor R2 and the second terminal of the resistor Re2 are respectively connected to A left channel audio signal and a right channel audio signal.

Preferably, the second end of the resistor R2 is grounded through a resistor R1, the second end of the resistor Re2 is grounded through a resistor Re1, the resistor R1 is connected in parallel with a capacitor C1, and the resistor Re1 is connected in parallel with a capacitor Ce1.

Preferably, the resistor R3 is connected in parallel with a capacitor CA, and the resistor Re3 is connected in parallel with a capacitor CB.

Preferably, the tone control circuit includes a left channel adjustment circuit and a right channel adjustment circuit, the input terminals of the left channel adjustment circuit and the right channel adjustment circuit are respectively connected to the output terminals of the amplifier U1A and the amplifier U1B, The audio signals output by the left channel adjustment circuit and the right channel adjustment circuit are respectively transmitted to the volume adjustment circuit, wherein: the left channel adjustment circuit includes a potentiometer RP1A, a potentiometer RP2A and a potentiometer RP3A, and the potentiometer The two ends of the potentiometer RP1A are respectively connected to the first end of the resistor R5 and the first end of the resistor R6, and the two ends of the potentiometer RP2A are respectively connected to the first end of the resistor R7 and the first end of the resistor R8, the potential The two ends of the potentiometer RP3A are respectively connected to the first end of the resistor R9 and the first end of the resistor R10, the sliding end of the potentiometer RP1A is connected to the first end of the capacitor C2, and the sliding end of the potentiometer RP2A is connected to the capacitor The first end of C4, the sliding end of the potentiometer RP3A is connected to the first end of the resistor R11, the second end of the resistor R5, the second end of the resistor R7 and the second end of the resistor R9 are connected to each other as the left The input end of the channel adjustment circuit, the second end of the resistor R6, the second end of the resistor R8 and the second end of the resistor R10 are all connected to the first end of the capacitor C6, the second end of the capacitor C2, the capacitor The second end of C4, the second end of resistor R11 and the second end of capacitor C6 are connected to each other as the output end of the left channel adjustment circuit; the circuit structure of the right channel adjustment circuit is the same as that of the left channel adjustment circuit same.

Preferably, the potentiometer RP2A is connected in parallel with a capacitor C3, and the potentiometer RP3A is connected in parallel with a capacitor C5.

Preferably, an inverter U2A and an inverter U2B are included, the output end of the left channel adjustment circuit is connected to the input end of the inverter U2A, and the output end of the inverter U2A is connected to the volume adjustment circuit One input end of the right channel adjustment circuit is connected to the input end of the inverter U2B, and the output end of the inverter U2B is connected to the other input end of the volume adjustment circuit.

Preferably, the inverter U2A and the inverter U2B are integrated in one NE5532 chip.

Preferably, the volume adjustment circuit includes a potentiometer RP4A and a potentiometer RP4B, the first end of the potentiometer RP4A is connected to the output end of the inverter U2A through a capacitor C7, and the second end of the potentiometer RP4A is grounded , the first end of the potentiometer RP4B is connected to the output end of the inverter U2B through the capacitor Ce7, the second end of the potentiometer RP4B is grounded, the sliding end of the potentiometer RP4A and the sliding end of the potentiometer RP4B are respectively As the two output terminals of the tone control circuit.

Preferably, it also includes a power supply circuit, the power supply circuit includes a rectifier bridge, a 7815 regulator U3A and a 7915 regulator U3B, the two AC terminals of the rectifier bridge are used to access the mains voltage, and the rectifier bridge The two DC terminals of the 7815 voltage regulator U3A are respectively connected to the input end of the 7915 voltage regulator U3B, the 7815 voltage regulator U3A and the 7915 voltage regulator U3B are connected to the common ground, and the 7815 voltage regulator U3A’s The input terminal is grounded through the filter capacitor C10, the input terminal of the 7915 voltage regulator U3B is grounded through the filter capacitor Ce10, the output terminal of the 7815 voltage regulator U3A and the 7915 voltage regulator U3B are respectively used to output positive and negative power supply voltages.

In the tone control circuit based on the NE5532 chip disclosed by the present invention, the left channel audio signal and the right channel audio signal connected to the preamplifier circuit are respectively amplified through the amplifier U1A and the amplifier U1B. Chip implementation, under the action of the NE5532 chip, the amplification, rectification, filtering, and fidelity processing of the sound signal are better realized, so that the tone control circuit outputs better sound quality, and at the same time eliminates unnecessary interference. In addition, The invention does not need to configure complicated multiple amplifier circuits, not only simplifies the circuit structure, but also reduces the product cost, and satisfies the needs of the market and users better.

Description of drawings

FIG. 1 is a block diagram of the tone control circuit of the present invention.

Figure 2 is a schematic diagram of the pre-amplifier circuit.

Figure 3 is a schematic diagram of the tone control circuit.

Figure 4 is a schematic diagram of the volume adjustment circuit.

Figure 5 is a schematic diagram of the power supply circuit.

Detailed ways

The present invention will be described in more detail below in conjunction with the accompanying drawings and embodiments.

The invention discloses a tone control circuit based on the NE5532 chip, as shown in Fig. 1 to Fig. 5, which includes:

A preamplifier circuit 1, its two input terminals are respectively used to access the left channel audio signal and the right channel audio signal, the preamplifier circuit 1 includes amplifier U1A and amplifier U1B, the amplifier U1A and amplifier U1B Integrated in a NE5532 chip, the amplifier U1A and the amplifier U1B are respectively used to amplify the left channel audio signal and the right channel audio signal;

A tone control circuit 2, the two input ends of which are respectively connected to the output ends of the amplifier U1A and the amplifier U1B, and the tone control circuit 2 is used to adjust the bass, middle tone and the middle tone of the two audio signals amplified by the amplifier U1A and the amplifier U1B respectively. adjustment and treble adjustment;

A volume adjustment circuit 3, the two input ends of which are respectively connected to the two audio signal output ends of the tone control circuit 2, and the volume adjustment circuit 3 is used to adjust the volume of the two audio signals.

In the above-mentioned tone control circuit, the audio signal of the left channel and the audio signal of the right channel connected to the preamplifier circuit 1 are respectively amplified by the amplifier U1A and the amplifier U1B. Under the action of the chip, the amplification, rectification, filtering, and fidelity processing of the sound signal are better realized, so that the tone control circuit outputs better sound quality, and at the same time eliminates unnecessary interference. In addition, the present invention does not need to configure complex The multi-amplification circuit not only simplifies the circuit structure, but also reduces the product cost, and better meets the needs of the market and users.

The pre-amplification part of the present invention preferably adopts NE5532 to build a negative feedback circuit, the purpose of which is to improve the working performance of the amplifier and improve the output signal quality of the amplifier. The gain is small, but it can improve some of the following performance indicators of the amplifier: 1. Reduce the nonlinear distortion of the amplifier, and realize it through AC negative feedback. 2. Broaden the frequency band of the amplifier and realize it through AC negative feedback. 3. Reduce the noise of the amplifier through AC negative feedback. 4. The working state of the temperature amplifier is realized through DC negative feedback.

Regarding the specific structure of the pre-amplifier circuit 1, in this embodiment, please refer to FIG. A resistor R3 is connected between the output terminal of the amplifier U1A and the inverting terminal, and the output terminal of the amplifier U1A is connected to an input terminal of the tone control circuit 2 through a resistor R4;

The non-inverting end of the amplifier U1B is grounded, the inverting end of the amplifier U1B is connected to the first end of the resistor Re2, a resistor Re3 is connected between the output end of the amplifier U1B and the inverting end, and the output of the amplifier U1B The end is connected to the other output end of the tone control circuit 2 through a resistor Re4;

The second end of the resistor R2 and the second end of the resistor Re2 are respectively connected to the left channel audio signal and the right channel audio signal.

Further, the second end of the resistor R2 is grounded through the resistor R1, the second end of the resistor Re2 is grounded through the resistor Re1, the resistor R1 is connected in parallel with a capacitor C1, and the resistor Re1 is connected in parallel with a capacitor Ce1. Wherein, the resistor R3 is connected in parallel with a capacitor CA, and the resistor Re3 is connected in parallel with a capacitor CB.

The working principle of the above-mentioned pre-amplifier circuit 1 is: the pre-amplifier part includes two left and right channels. Take the left channel as an example to analyze the working principle and the function of the main components. The signal is input to the inverting input of the amplifier U1A through the resistor R2 At the terminal, resistor R1 and resistor C1 play the role of reducing clutter interference, reducing input resistance, and matching impedance, among which resistor R1 also plays the role of preventing current offset. After being amplified by the amplifier U1A, it is output to the next stage through the resistor R4 for current limiting. The magnification is determined by the ratio of the resistor R2 to the resistor R3, specifically: the magnification Auf=R3/R2+1=100K/22K+1=6, in which the resistor R3 plays the role of negative feedback, and the capacitor CA and capacitor CB are two A 47pF capacitor, which can be regarded as a "lead capacitor", is used to overcome the nonlinear distortion caused by the high gain of integrated operational amplifiers such as NE5532, and can avoid the irritability when listening to audio for a long time. In practical applications, the capacitor CA, The role of capacitor CB will only be reflected when listening to the sound for a long time.

Regarding the concrete structure of tone control circuit 2, please refer to Fig. 3, described tone control circuit 2 includes left channel adjustment circuit 20 and right channel adjustment circuit 21, described left channel adjustment circuit 20 and right channel adjustment circuit The input terminals of 21 are respectively connected to the output terminals of the amplifier U1A and the amplifier U1B, and the audio signals output by the left channel adjustment circuit 20 and the right channel adjustment circuit 21 are respectively transmitted to the volume adjustment circuit 3, wherein:

The left channel adjustment circuit 20 includes a potentiometer RP1A, a potentiometer RP2A and a potentiometer RP3A, the two ends of the potentiometer RP1A are respectively connected to the first end of the resistor R5 and the first end of the resistor R6, the potential The two ends of the potentiometer RP2A are respectively connected to the first end of the resistor R7 and the first end of the resistor R8, and the two ends of the potentiometer RP3A are respectively connected to the first end of the resistor R9 and the first end of the resistor R10, the potential The sliding end of the potentiometer RP1A is connected to the first end of the capacitor C2, the sliding end of the potentiometer RP2A is connected to the first end of the capacitor C4, the sliding end of the potentiometer RP3A is connected to the first end of the resistor R11, the The second end of the resistor R5, the second end of the resistor R7 and the second end of the resistor R9 are connected to each other as the input end of the left channel adjustment circuit 20, the second end of the resistor R6, the second end of the resistor R8 and The second end of the resistor R10 is connected to the first end of the capacitor C6, the second end of the capacitor C2, the second end of the capacitor C4, the second end of the resistor R11 and the second end of the capacitor C6 are connected to each other as the left The output terminal of the channel adjustment circuit 20;

The circuit structure of the right channel adjustment circuit 21 is the same as that of the left channel adjustment circuit 20 .

Further, the potentiometer RP2A is connected in parallel with a capacitor C3, and the potentiometer RP3A is connected in parallel with a capacitor C5.

The above-mentioned tone control circuit 2 uses the principle of frequency characteristics of electronic circuits to artificially change the high, middle and low frequency components of the signal to improve the sound quality of the sound playback. Output, which adopts the attenuation negative feedback hybrid tone control circuit with high, middle and bass separately adjusted. The specific principles are as follows:

When adjusting the bass, the sliding end of the potentiometer RP3A slides to the uppermost end, the bass signal is sent to the inverting input end of the inverter U2A through the resistor R9 and the resistor R11, and the attenuation is the smallest. The potentiometer RP3A and the resistor R10 are connected in series on the negative feedback channel. Low signal negative feedback is the smallest, so the bass output is the largest at this time; when the sliding end of the potentiometer RP3A slides to the lower end, the bass signal is sent to the inverting input of the inverter U2A through the resistor R9, the potentiometer RP3A, and the resistor R11, and the attenuation is the largest , the signal negative feedback is also the largest, therefore, the bass output is the smallest at this time.

When the midrange is adjusted, when the sliding end of the potentiometer RP2A slides to the uppermost end, the midrange signal is sent to the inverting input terminal of the inverter U2A through the resistor R7, and the attenuation is the smallest. The potentiometer RP2A and the resistor R8 are connected in series on the negative feedback channel. The negative feedback of the midrange signal is the smallest, so the midrange output is the largest at this time; when the sliding end of the potentiometer RP2A slides to the lower end, the midrange signal is sent to the reverse input terminal of the inverter U2A through the resistor R7 and the potentiometer RP2A, and the attenuation is the largest , the signal negative feedback is also the largest, and the midrange output is the smallest at this time;

When adjusting the treble, when the sliding end of the potentiometer RP1A slides to the uppermost end, the treble signal is hardly attenuated, the negative feedback is also the smallest, and the treble output is the largest; when the potentiometer RP1A is slid to the bottom, the treble signal attenuation is the largest, and the negative feedback is also the largest. Treble output is minimal. Among them, capacitor C2 and capacitor C4 are coupling capacitors. After the signal is adjusted by the high-middle-bass circuit, it is sent to the NE5532 chip for re-amplification, and then the output is sent to the next-level circuit.

This embodiment also includes an inverter U2A and an inverter U2B, the output end of the left channel adjustment circuit 20 is connected to the input end of the inverter U2A, and the output end of the inverter U2A is connected to the volume One input end of the adjustment circuit 3 , the output end of the right channel adjustment circuit 21 is connected to the input end of the inverter U2B, and the output end of the inverter U2B is connected to the other input end of the volume adjustment circuit 3 . Further, the inverter U2A and the inverter U2B are integrated in one NE5532 chip.

Among them, the metal parts of the three potentiometers are all grounded with wires, which can eliminate interference. Inverters U2A and U2B are installed on the output side to increase the feedback depth when the potentiometer is adjusted downward, and attenuate the signal. Feedback depth decreases as the potentiometer is adjusted upwards, increasing the signal. Capacitor C2 has a small capacity, and it can be regarded as an open circuit for mid-range and bass signals. Capacitor C4 can be regarded as an open circuit for high-bass signals, and capacitor C3 can be regarded as an open circuit for high-bass signals. Capacitor C6 plays the role of eliminating the ballast, and the output 1K resistor divider can prevent the output short circuit.

In this embodiment, please refer to FIG. 4, the volume adjustment circuit 3 includes a potentiometer RP4A and a potentiometer RP4B, the first end of the potentiometer RP4A is connected to the output end of the inverter U2A through a capacitor C7, the The second end of the potentiometer RP4A is grounded, the first end of the potentiometer RP4B is connected to the output end of the inverter U2B through a capacitor Ce7, the second end of the potentiometer RP4B is grounded, and the sliding end of the potentiometer RP4A and the sliding end of the potentiometer RP4B are respectively used as the two output ends of the tone regulating circuit. Wherein, the potentiometer RP4A and the potentiometer RP4B are realized by a double potentiometer.

The above-mentioned volume adjustment circuit 3 can control the volume of the stereo two-channel signal by using a double-connected potentiometer, wherein the adjustment resistance of each connection of the double-connected potentiometer should be consistent, otherwise there will be an imbalance between the left and right channels. Phenomenon.

As a preferred mode, please refer to Fig. 5, the present embodiment also includes a power supply circuit 4, and the power supply circuit 4 includes a rectifier bridge (D1, D2, D3, D4), a 7815 voltage regulator U3A and a 7915 voltage regulator U3B, the two AC terminals of the rectifier bridge (D1, D2, D3, D4) are used to access the mains voltage, and the two DC terminals of the rectifier bridge (D1, D2, D3, D4) are respectively connected to 7815 voltage stabilizers The input terminal of the voltage regulator U3A and the input terminal of the 7915 voltage regulator U3B, the 7815 voltage regulator U3A and the 7915 voltage regulator U3B are connected to the common ground, the input terminal of the 7815 voltage regulator U3A is grounded through the filter capacitor C10, and the The input terminal of the 7915 voltage regulator U3B is grounded through the filter capacitor Ce10, and the output terminal of the 7815 voltage regulator U3A and the 7915 voltage regulator U3B are respectively used to output positive and negative power supply voltages.

In the above power supply circuit, four rectifier diodes IN4007 are used for rectification, and then two electrolytic capacitors are used for filtering and two 104 capacitors are connected in parallel, which can filter out the high-frequency noise introduced by the power transformer very well and make the power supply cleaner. The filter selection is brand-new, and absorbs high-frequency clutter, reduces the temperature rise of the capacitor, and ensures the filter effect of the power supply. At the same time, the three-terminal voltage regulator integrated circuit 7815 and 7915 voltage regulators for positive and negative power supplies are used to stabilize the voltage. After the voltage is stabilized by the three-terminal voltage regulator and filtered again by several small capacitors, they output +15V respectively. , -15V DC power supply for NE5532, making the power supply cleaner and more stable. Among them, small capacitors such as capacitor C10, capacitor Ce10, capacitor C13, and capacitor Ce13 can filter out ripples, reduce the influence of power supply on AC signals, and improve the signal-to-noise ratio. The output of the regulator tube is connected in parallel with a 100uF electrolytic capacitor to filter out residual interference waves , the electrolytic capacitor should not be too large, otherwise it will affect the tone, the middle tap of the transformer and the common terminal of the filter capacitor are connected together as the working ground of the circuit, and the light-emitting diode (LED) is used to judge whether the circuit is connected and whether there is current flowing .

In practical applications, the best power supply method for the audio system is to use separate power supplies for the front and rear stages, that is to say, separate power supplies for the preamplifier and the power amplifier. Relatively speaking, the preamplifier has high requirements for power supply ripple suppression, while the power amplifier More emphasis is placed on low frequency transient response. Before designing the power supply for the present invention, there are several methods worth noting: 1. It is necessary to use a large-capacity electrolytic capacitor for filtering, which can store enough electric energy to meet the requirements for electric power when the short-time spike signal of the sound occurs, so that the circuit Without clipping distortion. 2 In order to prevent the large-capacity filter capacitor from having a certain inductance and hindering the filtering of some high-frequency components, some electrolytic capacitors with decreasing capacity can be connected in parallel next to the filter capacitor, and a high-frequency small capacitor can be connected in parallel at the end to further improve the filtering effect . 3 Use toroidal transformer instead of vertical transformer. The internal resistance of the toroidal transformer is small and the power is large, and this kind of transformer is often used in the power amplifier to supply power.

In the tone control circuit based on the NE5532 chip disclosed by the present invention, the signal enters from the terminal JP1. First, the pre-amplifier circuit performs preliminary filtering and amplification, and then sends it to the tone control circuit to control and adjust the overall sound quality to obtain satisfactory sound quality. After inversion processing by NE5532, the volume is finally adjusted to a suitable volume by the volume adjustment circuit and then output from terminal JP2. During the whole process, the AC power supply uses components such as capacitors, Zener diodes, and three-terminal voltage regulators to filter out its own noise. The signal supplies a stable voltage to the entire circuit to make the circuit work normally. Compared with the prior art, the present invention compensates for the disadvantages of sound quality. Secondly, compared with the tone board made of LM1035 integrated block on the market, the present invention amplifies, rectifies, filters, and re-amplifies the sound. Finally, the sound quality has been significantly improved. In addition, the present invention realizes the improvement of the sound quality in a low-cost and easy-to-operate manner, which satisfies market demands and user demands better.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. All modifications, equivalent replacements or improvements made within the technical scope of the present invention shall be included in the protection scope of the present invention.

Claims (10)

1. a tone control circuit based on NE5532 chip, is characterized in that, comprises: A preamplifier circuit (1), its two input terminals are respectively used to insert the left channel audio signal and the right channel audio signal, the preamplifier circuit (1) includes an amplifier U1A and an amplifier U1B, the amplifier U1A and amplifier U1B are integrated in a NE5532 chip, and the amplifier U1A and amplifier U1B are respectively used to amplify the left channel audio signal and the right channel audio signal; A tone control circuit (2), its two input ends are respectively connected to the output ends of the amplifier U1A and the amplifier U1B, and the described tone control circuit (2) is used to perform bass tone respectively on the two-way audio signals amplified by the amplifier U1A and the amplifier U1B adjustment, midrange adjustment and treble adjustment; A volume adjustment circuit (3), the two input ends of which are respectively connected to the two audio signal output ends of the tone control circuit (2), and the volume adjustment circuit (3) is used for adjusting the volume of the two audio signals. 2. the tone control circuit based on NE5532 chip as claimed in claim 1, is characterized in that, the noninverting end of described amplifier U1A is grounded, and the inverting end of described amplifier U1A is connected to the first end of resistance R2, and described amplifier U1A A resistor R3 is connected between the output terminal of U1A and the inverting terminal, and the output terminal of the amplifier U1A is connected to an input terminal of the tone control circuit (2) through a resistor R4; The non-inverting end of the amplifier U1B is grounded, the inverting end of the amplifier U1B is connected to the first end of the resistor Re2, a resistor Re3 is connected between the output end of the amplifier U1B and the inverting end, and the output of the amplifier U1B End is connected to the other output end of tone control circuit (2) by resistance Re4; The second end of the resistor R2 and the second end of the resistor Re2 are respectively connected to the left channel audio signal and the right channel audio signal. 3. the tone control circuit based on NE5532 chip as claimed in claim 2, is characterized in that, the second end of described resistance R2 is grounded through resistance R1, the second end of described resistance Re2 is grounded through resistance Re1, and described resistance R1 is connected in parallel with a capacitor C1, and the resistor Re1 is connected in parallel with a capacitor Ce1. 4. The tone control circuit based on the NE5532 chip according to claim 2, wherein the resistor R3 is connected in parallel with a capacitor CA, and the resistor Re3 is connected in parallel with a capacitor CB. 5. the tone control circuit based on NE5532 chip as claimed in claim 1, is characterized in that, described tone control circuit (2) comprises left sound channel adjustment circuit (20) and right sound channel adjustment circuit (21), so The input ends of the left channel regulation circuit (20) and the right channel regulation circuit (21) are respectively connected to the output ends of the amplifier U1A and the amplifier U1B, and the left channel regulation circuit (20) and the right channel regulation circuit ( 21) The output audio signals are respectively transmitted to the volume adjustment circuit (3), wherein: The left channel adjustment circuit (20) includes a potentiometer RP1A, a potentiometer RP2A and a potentiometer RP3A, and the two ends of the potentiometer RP1A are respectively connected to the first end of the resistor R5 and the first end of the resistor R6, so The two ends of the potentiometer RP2A are respectively connected to the first end of the resistor R7 and the first end of the resistor R8, and the two ends of the potentiometer RP3A are respectively connected to the first end of the resistor R9 and the first end of the resistor R10, so The sliding end of the potentiometer RP1A is connected to the first end of the capacitor C2, the sliding end of the potentiometer RP2A is connected to the first end of the capacitor C4, the sliding end of the potentiometer RP3A is connected to the first end of the resistor R11, The second end of the resistance R5, the second end of the resistance R7 and the second end of the resistance R9 are connected to each other as the input end of the left channel adjustment circuit (20), the second end of the resistance R6, the second end of the resistance R8 Both the second end and the second end of the resistor R10 are connected to the first end of the capacitor C6, the second end of the capacitor C2, the second end of the capacitor C4, the second end of the resistor R11 and the second end of the capacitor C6 are connected to each other. Connected as the output end of the left sound channel adjustment circuit (20); The circuit structure of the right sound channel adjustment circuit (21) is the same as that of the left sound channel adjustment circuit (20). 6 . The tone control circuit based on the NE5532 chip according to claim 5 , wherein the potentiometer RP2A is connected in parallel with a capacitor C3 , and the potentiometer RP3A is connected in parallel with a capacitor C5 . 7. the tone control circuit based on NE5532 chip as claimed in claim 5, is characterized in that, comprises an inverter U2A and an inverter U2B, and the output end of described left channel adjustment circuit (20) is connected in inverter The input end of the phaser U2A, the output end of the inverter U2A is connected to an input end of the volume adjustment circuit (3), and the output end of the right channel adjustment circuit (21) is connected to the input of the inverter U2B terminal, and the output terminal of the inverter U2B is connected to the other input terminal of the volume adjustment circuit (3). 8. The tone control circuit based on the NE5532 chip as claimed in claim 7, wherein the inverter U2A and the inverter U2B are integrated in one NE5532 chip. 9. the tone control circuit based on NE5532 chip as claimed in claim 7, it is characterized in that, described volume control circuit (3) comprises potentiometer RP4A and potentiometer RP4B, and the first end of described potentiometer RP4A passes capacitor C7 is connected to the output end of the inverter U2A, the second end of the potentiometer RP4A is grounded, the first end of the potentiometer RP4B is connected to the output end of the inverter U2B through a capacitor Ce7, and the potentiometer RP4B is connected to the output end of the inverter U2B. The second end is grounded, and the sliding end of the potentiometer RP4A and the sliding end of the potentiometer RP4B are respectively used as two output ends of the tone regulating circuit. 10. the tone control circuit based on NE5532 chip as claimed in claim 1, is characterized in that, also comprises a power supply circuit (4), and described power supply circuit (4) comprises rectifier bridge (D1, D2, D3, D4) , 7815 voltage regulator U3A and 7915 voltage regulator U3B, the two AC ends of the rectifier bridge (D1, D2, D3, D4) are used to access the mains voltage, and the rectifier bridge (D1, D2, D3, D4 ) are respectively connected to the input end of the 7815 voltage regulator U3A and the input end of the 7915 voltage regulator U3B, the 7815 voltage regulator U3A and the 7915 voltage regulator U3B are connected to the common ground, and the 7815 voltage regulator U3A The input terminal of the 7915 voltage regulator U3B is grounded through the filter capacitor C10, the input terminal of the 7915 voltage regulator U3B is grounded through the filter capacitor Ce10, and the output terminal of the 7815 voltage regulator U3A and the 7915 voltage regulator U3B are respectively used to output positive and negative power supply voltages.