Keywords: LM1875, 6N2, 6N3 amplifier circuit diagram
Although the use of toners in modern electronic technology applications is small, it is also favored in some areas, in particular the sound circuits in some areas, in particular the sound circuits, in particular in some areas. This is a mixed amplifier consisting of "靓" tube and audio integrated circuit. The amplifier is subjected to the electron tube, the audio-specific integrated circuit AD711 and LM1875, the circuit is small, the output impedance is low, the dynamic range is large, and good sound quality can be guaranteed. Due to the combination of integrated circuits, the circuit is simple, suitable for enthusiasts, especially "enthusiasts" homemade. References are also available for the design of audio products.
First, the principle of circuit working principle is shown in the figure.
This circuit only draws the left channel portion and the right voice. The circuit uses a double tripod 6N2 tube constitutes a line input amplifier (half of the VE1L of 6N2 is used for the left one channel, and the other half Ve1R is used for the right channel). R2 is a direct bias resistor of the input stage. When the screen flow IAO flows through R2, a DC voltage EG of about 1.5 V is generated, and the gate drain resistor R1 is added to the gate of VE1L, and the negative gate pressure of the line amplifier is formed. At this time, VE1L operates in a matrix, has good linearity. Another effect of R2 is to generate appropriate AC feedback on the source signal, so that the distortion is further reduced, and the stability is further improved; the third effect of R2 is to form a tone feedback. This input stage has a high-input impedance, high dynamic range, and the transient response is good, which is all necessary for Hi-Fi. Attenuation Tone Control Network (TCN) is inserted between the front and rear stages. The audio signal output from the VE2LA cathode K on the SRPP circuit is sent to the 3 foot of the post-stage integrated circuit IC1 through the volume potentiometer VR3; another way is fed by the TCN network to the cathode of the line amplifier VE1L. This combination form can effectively suppress rookies and distortion, and maintain the regulatory properties of the attenuating TCN. After the signal is amplified by Ve1L, the signal is output from the anode, and the capacitance C2 is coupled to the power amplifier VE2 composed of the tube 6n3 excellent in high frequency characteristics, and the two triodes inside are connected to the parallel regulating push-pull circuit SRPP. The circuit is characterized by small distortion, low output impedance, large dynamic range, and is fully adapted to various power amplifiers composed of IC, FET, TR, VAL, and the like. In Fig. (A), the capacitance C4, C5, the resistor R7, R8, and the potentiometer VR1 constitute a bass control network. When VR1 is up again, the network consisting of C5 and C4 increases the negative refueling amount of low audio signals, and the bass is relatively weak; the counter VR1 is down-regulated, and the bass will be relatively enhanced. Capacitor C9, C10, resistor R9, R10, and potentiometer VR2 constitute a treble control network. When VR2 is up again, the negative refueling amount of the high tone frequency signal increases, the treble is relatively weak; the reverse VR2 is down-regulated, and the treble will be relatively enhanced. In the amplifier circuit, it is desirable to get high fidelity, high power output, general power op amp to provide greater power, but most of the shortcomings of distortion, linearity. If the front end of the high-power IC is inserted into a linear, distortion is small, and the power amplifier IC2 is in the feedback link of IC1, it can achieve the efficacy of the long-term extension. This connection is called "turbocharged combination" (TCC). The integrated circuit IC1 (AD711) and IC2 (LM1875) constitute a TCC amplifier, and the RC network is constituted by C11, R12, R13 in the TCC network, providing an appropriate phase compensation for the audio signal, so that IC1, IC2 frequency sound area is stable. Figure (b) is a machine power supply circuit diagram. The high-pressure high pressure of the tube is directly supplied by the city's electric rectification. The three filaments of the two tubes are connected in series, and the power supply is greatly concise by a set of AC 18V. Another group of AC 18V via bridge rectification, C15, C16, C17, filter generated ± 25V is IC1, IC2 power supply.
Be
Be
Second, the selection of components VE1 Select 6N2, VE2 Select 6N3, integrated circuit IC1 Select the AD711, IC2 Select LM1875, low voltage filter capacitance C16, C17 Select 70VW series, high voltage filter capacitor C19 Select the CD17H series, C15 Select Polyester Capacitance, C18 Select Polypropylene capacitance, C6, C8 select tantalum electrolytic capacitance, C12, C13 selected CD03HV high voltage electrolytic capacitance. The metal film series is selected for all electrical resistance. The potentiometer uses the KK210 series. Component parameters are selected as the circuit diagram.
Third, the production and debugging methods are selected as required, and they can be successfully installed, and they can be successful and no need to debug. Electronic pipes should be installed with an electronic pipe, and the integrated circuit should be allowed to remotely from the tube to avoid overheating of integrated circuits. After the circuit is installed, it should be loaded into a chassis with heat dissipation holes, and the volume potentiometer, high and low tone potentiometer is safe on the chassis panel, which is convenient for use adjustment.
Our other product:
