CN203151436U

CN203151436U - Stereophonic high-fidelity disc and prime amplifier

Info

Publication number: CN203151436U
Application number: CN 201320149134
Authority: CN
Inventors: 邰若鹏
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-03-28
Filing date: 2013-03-28
Publication date: 2013-08-21
Anticipated expiration: 2023-03-28

Abstract

The utility model discloses a stereophonic high-fidelity disc and prime amplifier. Each amplification circuit of the stereophonic high-fidelity disc and prime amplifier comprises a pre-amplification stage and a power output stage, an audio signal input terminal of an adapterization input socket of each amplification circuit is in electric connection with the input end of the first stage of each pre-amplification stage, an audio signal input terminal of a line input socket is grounded through a slide rheostat, and a center tap of each slide rheostat is in electric connection with the input end of the last stage of each pre-amplification stage. A grounding terminal of each line input socket is directly grounded, an intermediate terminal of each line input socket is in electric connection with the output end of the penultimate stage of each pre-amplification stage, and a normally closed contact which is disconnected automatically when each line input socket is inserted is in electric connection between the audio signal input terminal and the intermediate terminal of each line input socket. According to the stereophonic high-fidelity disc and prime amplifier, the line input sockets with the normally closed contacts are adopted for switching of adapterization and line input, wiring is simplified, two switches are omitted, and induction hum is prevented from being increased.

Description

A kind of stereo high fidelity disc and pre-amplifier

Technical field

The utility model relates to a kind of power amplifier, relate in particular to a kind of can be to the audio signal of disc output and stereo high fidelity disc and the pre-amplifier that carries out power amplification by the pickup signal of inputs such as microphone.

Background technology

Application number is that 02249551.7 Chinese utility application discloses a kind of active audio amplifier, the amplifier of this active audio amplifier comprises an electron tube at least, the electron tube that adopts is used for preposition amplification, power amplification and signal and shows, the processing procedure of audio signal is: audio signal is imported by exporting through loudspeaker after the amplification of electron tube prime, the power amplification of electron tube final stage again, the document is pointed out, the sound that adopts these electron tubes that loud speaker is sent has more the simulated sound speciality, sense of hearing is softer, and is more natural.This shows, adopt electron tube can make high-fidelity power amplifier (sound amplifier), and the periphery circuit design of electron tube can also influence the acoustical quality of power amplifier.

Fig. 1 shows a kind of existing previous amplifier circuit, this circuit has adopted big loop negative feedback, be about to the negative electrode that output signal feeds back to the triode that carries out first order amplification, because big loop negative feedback has inevitable time delay, thereby produce bigger transient intermodulation; In addition, the output impedance of circuit shown in Figure 1 is higher, so this circuit structure also has the defective that can not be complementary with the back level of low input impedance.

The utility model content

The purpose of this utility model is to provide a kind of circuit structure simple, and can prevent stereo high fidelity disc and pre-amplifier that induction hum strengthens.

The technical solution adopted in the utility model is: a kind of stereo high fidelity disc and pre-amplifier, comprise two identical amplifying circuits and the power circuit of power supply is provided for two amplifying circuits, described amplifying circuit comprises preamplifier state and power output stage, described amplifying circuit is provided with the pickup input socket, circuit input socket and audio frequency accessory power outlet, audio signal input end of described pickup input socket is electrically connected with the input of the first order of preamplifier state, audio signal input end of described circuit input socket is through slide rheostat ground connection, the centre tap of slide rheostat is electrically connected with the input of the final stage of preamplifier state, the direct ground connection of the earth terminal of circuit input socket, the intermediate terminal of circuit input socket is electrically connected with the penultimate output of preamplifier state, wherein, be electrically connected with the normally closed contact of automatic disconnection when the circuit input plug inserts between audio signal input end of circuit input socket and the intermediate terminal.

Wherein, the power transformer of described power circuit comprises two secondary coils, first power output circuit that first secondary coil constitutes through first current rectifying and wave filtering circuit provides operating voltage for the anode of all electron tubes of amplifying circuit, two lead-out terminals of the second source output circuit that the second subprime coil constitutes through second current rectifying and wave filtering circuit directly are electrically connected with the filament of all electron tubes of amplifying circuit, first, the electronegative potential output of second source output circuit is electrically connected mutually, and first, the current potential of the electronegative potential lead-out terminal of second source output circuit is higher than earthing potential.

The electronegative potential lead-out terminal of described first, second power output circuit is through the 3rd grounding through resistance.

Wherein, described preamplifier state adopts three grades of triodes cloudy amplifying circuit altogether.

Wherein, the anode of the triode of first order amplifying circuit is electrically connected with the grid of the triode of second level amplifying circuit through first electric capacity and first resistance, the grid of the triode of second level amplifying circuit is electrically connected with the anode of the triode of second level amplifying circuit through RIAA equalizing network and second electric capacity, and the potential point between RIAA equalizing network and second electric capacity is electrically connected with the intermediate terminal of circuit input socket as the output of described final stage amplifying circuit.

Wherein, described power output stage adopts triode negative electrode output circuit.

The beneficial effects of the utility model are:

1, the circuit input socket with normally closed contact is adopted in the conversion of the pickup of stereo high fidelity disc of the present utility model and pre-amplifier and circuit input, has simplified wiring, has saved two switches, and has prevented the increasing of induction hum;

2, the input of the pickup of stereo high fidelity disc of the present utility model and pre-amplifier and circuit input are the high impedance input, can significantly reduce the access of this machine to the influence in high impedance signal source, make the output voltage of signal source not produce remarkable reduction;

3, because stereo high fidelity disc of the present utility model and pre-amplifier do not adopt big loop negative feedback, the transient intermodulation that makes main feedback signal produce the time delay of input signal greatly reduces, and makes this machine subjective sense of hearing preferably be arranged big under dynamically;

4, the filament of each electron tube of stereo high fidelity disc of the present utility model and pre-amplifier adopts direct current supply, and the above earth potential of filament is raised, can significantly reduce because defective insulation between filament and negative electrode, filament to the hum that the distributed capacitance between cathode emission electronics, filament and negative electrode etc. causes, improve the noise level of this machine.

Description of drawings

Fig. 1 shows existing previous amplifier circuit structure;

Fig. 2 is a kind of circuit diagram of implementing structure according to stereo high fidelity disc of the present utility model and pre-amplifier.

Embodiment

As shown in Figure 2, stereo high fidelity disc of the present utility model and pre-amplifier comprise two identical amplifying circuits (dual track that is amplifier all adopts this circuit structure) and the power circuit of power supply are provided for two amplifying circuits, this amplifying circuit comprises preamplifier state and power output stage, described amplifying circuit is provided with pickup input socket IN1, circuit input socket IN2 and audio frequency accessory power outlet OUT, audio signal input end of pickup input socket IN1 is electrically connected with the input of the first order of preamplifier state, audio signal input end of circuit input socket IN2 is through slide rheostat R5 ground connection, the input of the centre tap of slide rheostat R5 and the final stage of preamplifier state (be the third level for embodiment shown in Figure 2) is electrically connected, the direct ground connection of earth terminal of circuit input socket IN2, the intermediate terminal of circuit input socket IN2 and the inferior final stage of preamplifier state (are the previous stage of the final stage of preamplifier state, be the second level for embodiment shown in Figure 2) output be electrically connected, wherein, be electrically connected with the normally closed contact of automatic disconnection when the circuit input plug inserts between audio signal input end of circuit input socket IN2 and the intermediate terminal.After circuit input socket IN2 inserts the circuit input plug, by the normally closed contact in it disconnect with the final stage amplifying circuit before being connected of circuit, the audio signal of via line input socket IN2 input is directly exported through final stage amplifying circuit and power output stage; When in pickup input socket IN1, inserting the pickup input plug, normally closed contact by circuit input socket IN2 inside links together inferior final stage and final stage amplifying circuit, makes through the audio signal of pickup input socket IN1 input to export through the multistage amplifier circuit power output stage.

As shown in Figure 2, the power transformer of power circuit comprises two secondary coils, the power input terminal IN3 of primary coil inserts civil power, first power output circuit that the first secondary coil T1 constitutes through first current rectifying and wave filtering circuit provides operating voltage for the anode of all electron tubes of amplifying circuit, two lead-out terminals of the second source output circuit that the second subprime coil constitutes through second current rectifying and wave filtering circuit directly are electrically connected with the filament of all electron tubes of amplifying circuit, first, the electronegative potential output of second source output circuit is electrically connected mutually, and first, the electronegative potential lead-out terminal of second source output circuit makes the current potential of the two be higher than earthing potential through the 3rd resistance R 3 ground connection.

Among the embodiment shown in Figure 2, preamplifier state adopts three grades of triode Q1, Q2, Q3 cloudy amplifying circuit altogether, power output stage sampling triode Q4 negative electrode output circuit.

In addition, the anode of the triode Q1 of the first order of preamplifier state is electrically connected with the grid of the partial triode Q2 of preamplifier state through first capacitor C 1 and first resistance R 1, the grid of triode Q2 is electrically connected with the anode of triode Q2 through RIAA equalizing network W and second capacitor C 2, and RIAA equalizing network W is electrically connected as the intermediate terminal of partial output with circuit input socket IN2 with potential point between second capacitor C 2.

The above is the utility model preferred implementation only, is not to limit practical range of the present utility model, and the equivalence of doing in protection range of the present utility model changes and modifies in every case, all should think to have fallen in the protection range of the present utility model.

Claims

1. a stereo high fidelity disc and pre-amplifier, comprise two identical amplifying circuits and the power circuit of power supply is provided for two amplifying circuits, described amplifying circuit comprises preamplifier state and power output stage, it is characterized in that: described amplifying circuit is provided with the pickup input socket, circuit input socket and audio frequency accessory power outlet, audio signal input end of described pickup input socket is electrically connected with the input of the first order of preamplifier state, audio signal input end of described circuit input socket is through slide rheostat ground connection, the centre tap of slide rheostat is electrically connected with the input of the final stage of preamplifier state, the direct ground connection of the earth terminal of circuit input socket, the intermediate terminal of circuit input socket is electrically connected with the penultimate output of preamplifier state, wherein, be electrically connected with the normally closed contact of automatic disconnection when the circuit input plug inserts between audio signal input end of circuit input socket and the intermediate terminal.

2. stereo high fidelity disc according to claim 1 and pre-amplifier, it is characterized in that: the power transformer of described power circuit comprises two secondary coils, first power output circuit that first secondary coil constitutes through first current rectifying and wave filtering circuit provides operating voltage for the anode of all electron tubes of amplifying circuit, two lead-out terminals of the second source output circuit that the second subprime coil constitutes through second current rectifying and wave filtering circuit directly are electrically connected with the filament of all electron tubes of amplifying circuit, first, the electronegative potential output of second source output circuit is electrically connected mutually, and first, the current potential of the electronegative potential lead-out terminal of second source output circuit is higher than earthing potential.

3. stereo high fidelity disc according to claim 1 and pre-amplifier, it is characterized in that: the electronegative potential lead-out terminal of described first, second power output circuit is through the 3rd grounding through resistance.

4. according to each described stereo high fidelity disc and pre-amplifier in the claim 1 to 3, it is characterized in that: described preamplifier state adopts three grades of triodes cloudy amplifying circuit altogether.

5. stereo high fidelity disc according to claim 4 and pre-amplifier, it is characterized in that: the anode of the triode of first order amplifying circuit is electrically connected with the grid of the triode of second level amplifying circuit through first electric capacity and first resistance, the grid of the triode of second level amplifying circuit is electrically connected with the anode of the triode of second level amplifying circuit through RIAA equalizing network and second electric capacity, and the potential point between RIAA equalizing network and second electric capacity is electrically connected with the intermediate terminal of circuit input socket as the output of described final stage amplifying circuit.

6. stereo high fidelity disc according to claim 4 and pre-amplifier is characterized in that: described power output stage employing triode negative electrode output circuit.