Cave panel DIY ear, Headphone Amplifier
Keywords: headphone amplifier
Author: lemontreenm
I had a USB sound card for a few days ago, and the sound listened was not bad, and it was more clear than the computer's integrated sound card. But I always feel that the thrust is not very good. Especially when using colleagues, this feeling is more obvious. So I want to done to increase the thrust, I want to do it. Do one! ! ! 1, first is the selection circuit. I have been looking for a long time online, there are many simple ear-up circuits, basically very different. It is a simple zoom in amplification with op amps, with limited load capacity. Although I am learning chemistry, I don't understand the circuit. However, according to basic circuit knowledge, there are many deadly defects such as distortion in these so-called simple incents. If the sound quality drops, what I still do. Be sure to do it. Finally, I've watched the "50th Anniversary Edition" ear. Although I have been four years, this ear of this ear is made by people, but the classic is the classic worth a try! The following is an improved circuit diagram of the "50th Anniversary Edition" ear, from the Internet. 2, the first step in the principle and improvement is of course research transmission path map. Otherwise, don't know which place is there. The principle of this circuit is to control the volume using a double 50K potentiometer. NE5532 doing primary zoom, and controls the total magnification, and the large loop circuit is negative feedback. The BD139, the BD140 triode is composed of the tube to increase the output power. Understand the principle, the next step is to see if there is any place to improve. After some analysis, the improved place is still there. First reduce the total magnification, and the 22k resistors R11 and R22 are changed to 10K. The total magnification is controlled within 10 times. Secondly, the stability of the power supply power supply is enhanced, and the 78L12 and 79L12 circuits replace the original regulator tube and the resistance composed of voltage regulatory circuits. The improvement method is determined, and the circuit is arranged in the next step. 3, single-way layout Since the circuit is not simple, it is still relatively high for people who are not electronic majors. So first use the software to pick it up. There is only 45 * 90mm cave board on your hand, use it. Follow this size. It is a finished layout. Of course, this figure is mapped, and it is still necessary to use the actual situation to be flexible. Next, everyone will definitely think that it is welded. Let everyone be disappointed. 4, the preparation of the material I am DIY just started, so the hand is less, most things need to be purchased. These include suitable resistance, capacitance, special models of diodes, potentiometers, triodes, op amps. The best place to purchase is of course X Bao. Fortunately, the place where you work is close to the electronic market, so give priority to the local seller, go to the door. Otherwise postage costs expensive. Because it is almost impossible to collect all components in a store. The following is some of the components (resistors, diodes, regulators, three ends, triodes, capacitors, plugins, etc.) I have purchased from 6 different stores. It is mainly afraid to buy the legendary fake 5532. It's really true, and you will know if you come back. 5, welding is ready for materials, nature is starting to weld. I am sighing the rookie is a rookie, and there are several setbacks in the middle, and I also sacrificed several younger brothers (components) for the first time, I watched the wrong drawing. Wait until all the capacitors were welded before they found that the soldering was reversed. No way, remove it. After a night, I finally recovered the loss. This time, I didn't make a mistake, and there was a wiring of the rear of the cave board after most of the metals soldered. Because the cave board itself is no line. I have been almost one week before and after welding. The welding eyes have spent the finished product. Figure 6. The last step of the circuit is of course power-on test. There is no dual 12V power supply during period. So only once again with the power of online shopping. Some friends who have just started may ask. Why do you want to use transformers, switching power supply is not better? ? What I want to say is that it is not suitable for the switching power supply in the audio circuit. The high frequency interference is large, the most appropriate or transformer. In order to ensure safety when I first power off, I didn't have it, and I have proved that I am right. Because I smelled the taste of clinker. After checking, 79L12 burned. It turned out that I made a definition of the pin, and I always thought that the same approach is the same as 78L12. It turned out to be different. In order to understand this, I have a total of 3 79L12 and a 78L12. Distressed ... This is the photo of the middle experiment, the 79L12 no suspected hanging after the photo is changing the body of the three ends of the three ends of the three ends of the three ends, and the op amps mourn for you ... 7. When answering the audition, I used three tone sources, namely Meizu M6-SL, the radio function of domestic Hisense mobile phones, and homemade USB sound cards. Meizu M6-SL is relatively low due to the MP3 file rate in the inside, after hearing 20 seconds, I was thrown one side. The radio function of Hisense mobile phone is also despised, 20 seconds, I also gave my colleague (not mine, can't throw). The last use of homemade USB sound cards with high yield audio files on my computer have achieved better results. Here you introduce my homemade USB sound card, which uses the PCM2912A program. It is my first work. For audio files, individual feels that there is a difference between 224K, 192K, and 320K MP3 files. It can't be used in the previous integrated sound card. Playing software, listening to multi-meter music and Windows Media Center, have to say a lot of playback effects of Windows Media Center. Domi is directly abandoned. Of course, these are not heard when using a computer integrated sound card. That is, use my homemade USB sound card, if you don't match the ear, you can't listen. In addition to increasing the thrust, it is to show the sound of the performance, so some flaws you can't hear because of the insufficient lifting. It should be said that this ear is not doing too much modification. In the case where the source is given, the sound is compared, and the three-frequency is balanced. The bass is disappointed, and the bass did not get special protrude. People control and middle sound control can laugh, and measurement shows that the spin and vocals are very powerful. Finally, please see how the picture I am listening is now ready to print the PCB board, and several DIY friends around you have already added 6 sets. Welcome everyone to discuss and communicate.
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