Use the city's electricity to provide the on-board working power supply, Vacuum Tube Power Supply
Keywords: Using the market directly providing the on-board working power supply
In the amateur production of electronic pipe power delivery, the production of output transformers and power transformers is a cumbersome thing. Moreover, the efficiency problem of the power transformer, the volumetric weight problem is a headache. It is now introduced that a port-like market (220V lighting), the production method of electronic pipe power placed directly supplied to the electronic pipe screen after rectification filtering. For reference.
It is necessary to provide a working power supply directly to the electronic pipe on the electronic pipe. It must solve two problems: 1. Use security issues. 2. Isolation problems between pre-predecessors and speakers. Let's talk about isolation problems between pre-predecessors and speakers. See Figure 1 for the circuit. From the schematic diagram of Figure 1, we can see that a linear photocouplex system is composed of C1, R1, R2, and photocoupler GD. It has a quarantine effect of preamplis and post-colurate amplifiers, and is a separate power system, a separate ground loop that prevents the noise string introduced by the potential difference between the ground, improves the stability of the entire amplifier system. Sex and fidelity. The output transformer of the active amplifier completed the isolation of the amplifier and the speaker system. Its tube filament and photocouplex system are supplied by a small capacity power transformer, which has neonds the weight of the whole machine, and reduces the production cost, saving the trouble of winding high pressure coils. Due to the direct supply of electricity, the power supply is much lower than the power transformer, which makes the playback sound faster, more in line with the requirements of modern sound source. The method of using the main electricity supply is not suitable for each electronic tube. It is now introduced that several electronic pipe power discharge circuits using the main electricity supply. It is interested in readers to try, and it will be successful according to the map.
1, single-ended amplifier
Single-ended power amplifiers are a circuit form of the most affected friends in the electronic management power amplifier, which has a rich orcharged harmonics, especially with sound flavor. According to the data of the main wavelength flow filtering, the DC voltage is 310V after filtering, and two single-ended A power amplifier circuits are designed in Fig. 2, and Fig. 3. From the circuit of Figure 2, we can see this is a typical small power single-ended power amplifier circuit. The signal is sent from the 4.7 μF capacitance and 100 Ω resistors into an input isolation circuit composed of photocoupler 4N36, 2.2K The resistor provides a working current in the light-emitting diode in the photocoupler. As the input signal changes, the light-emitting strength of the light-emitting diode also changes, and after receiving the photosensitive triode in the photocoupler, the change in the photocopy electrode current is caused, which is coupled to the photosensitive triode collector 100 Ω resistor. Audio signal is powered by power supply. This completes the input signal with the power amplifier to complete the input signal. Figure 2 The last level power amplifier tube in the circuit selected a common 6P1 or 6P14 tube. The pins of the two tubes are identical and can be directly interchanged. The biggest difference between the two is that the optimum load impedance is different, and 6P1 is 5.5K, 6P14 is 4.5K. The DC voltage value of the two tubes in the electronic management manual is a DC 250V. In this example, the DC voltage is 310V, and since theoretically, it has exceeded the screen pressure value provided on the electronic management manual and the maximum score of the tube. . However, after a long practice, the voltage drop caused by the output transformer complicated primary coil (about 500 Ω). The actual DC voltage of the electronic tube is approximately 280 volts. There is no adverse effect after hundreds of hours, and the output power is increased than the data provided on the manual. The 6P1 full power is 5W, 6P14 full The power is 6W.
Figure 3 is substantially identical in the circuit form in the circuit form, only a 6P3P tube having a greater power amplifier tube, which is identical to FIG. 2, and is not detailed. Use 6P3P as a power amplifier tube, the output power can reach 10W at 310V screen, enough to drive some large diameter speakers in an area slightly larger. Moreover, the optimum load impedance of 6P3P is relatively low to 3.5K, which provides a convenient for homemade output transformers.
Figure 3 The measured technical indicators of the circuit of the circuit are as follows:
Maximum no loss output power: 10W (rl = 8Ω)
Frequency response: 30Hz-22kHz (± 3dB)
Total harmonic distortion: 1.5% (1W) signal to noise ratio: 96DB output transformer winding data: core size: 26mm tongue, 32mm stack, core cross-sectional area of about 7.6mm 2 primary winding Round number: total turns The number is 2400, divided into 4 segments, each 600 初 初 线 径::: 强.. 强 强 强 强. 强............................. 高..
The coil is wound, and the coating is improved and then inserted and then inserted into the core. The core is inserted, and the air gap is separated from 0.5 mm insulated paper. After the insertion, it can be dried. The impedance ratio can be simply tested with an alternating current, with a 220V alternating current in the primary, and 11V Alternating current should be used in the secondary. The output isolation of the above two circuits is implemented using an output transformer. All components in the red dot line box in the production of the production are not in contact with the casing. When debugging, it should be put on the insulated glove to prevent electric shock. In the above two circuits, simply adjust the resistance of the photosensitive triode set electrode resistance, the input amplitude can be changed to meet the needs of the full power output. Optocouplers can also be used in other models, as long as the oral foot transmission ratio is 100%, the transmission speed is greater than 4 ms. The output transformer of 6p1 and 6p14 is preferably used, and the self-made difficulty is slightly large. Other components can be selected according to the condition of enthusiasts. The triple-end regulator should be equipped with a heat sink having a large enough.
2, 1-class push pull amplifier
When the power requirements are large, the circuit form of the electronic pipe push amplifier can be selected, and the 310V DC as a screen of the power supply is used as the electronic tube power amplifier of the screen power supply with the mains. The maximum output power can reach 20W. It is fully able to meet the family. The need for playback music is played. There are many kinds of push-pull amplifier circuits, compare classic mature, William amplifier circuits, but Willianson amplifying the third-class triplayer used by the push-pull amplified power tube, so the output power is smaller. I combine the Willianson circuit with the end-level push-pull power tube to design the following power amplifier circuit, which has excellent performance of the Williamson amplification circuit, and it can greatly improve the output power of the power amplifier, and the actual use of the year good results. A power amplifier circuit diagram, three kinds of pick-up of the final push-pull power pipe.
Figure 4 The final push-pull power amplifier tube in the circuit can also be selected from the 6P3P tube, the maximum output power can be increased to 22W, and the two power amplifiers are in 310V screen, and the 1-class working state of the A-B-1 work is attached.
The output transformer of the above circuit uses a 25W push-pull output transformer. The production data is shown in Figure 6, which is the same as the single-ended output transformer as the single-ended output transformer.
In addition to the photocouplex system and output transformer in the circuit, all components are in communication with the city, and must pay attention to safety during the production of debugging.
After the above-mentioned two-circuit form, the electronic tube power discharge circuit is equipped, and all the solder joints and other conductive parts of the city electricity are applied to avoid the occurrence of electric shock accidents.
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