Capacitors are one of the commonly used electronic components, and friends who are professional in electronics have more or less understanding of capacitors. However, in the process of using capacitors, how do we use a variety of different capacitors together? In order to answer your questions, this article will introduce the matching of capacitors, mainly to introduce the matching of electrolytic capacitors and film capacitors.
In an electrical appliance, especially in CDs, capacitors play a huge role, because in audio equipment, the amount of capacitors is quite large, especially in the middle of CDs, many integrated blocks are necessary and there is almost no choice. , Unlike the amplifier tube in the power amplifier, there are many choices. Therefore, in the cd, once the integrated block is fixed, you can only choose the capacitor and the resistance. Because the resistance has a smaller effect on the sound of the sound than the capacitor Many, so the capacitance is our top priority. Of course, the effect of resistance is relatively small. For example, the input and output resistances have a greater impact on the equipment, but other resistances have less impact.
Since a large number of capacitors are needed in the equipment, a series of questions arise. Which one should be used by so many brands? How should these capacitors be matched? In the domestic equipment, there are not many designers who pay attention to these problems. , Especially the latter problem is less researched. This is an important reason why domestic equipment is similar to foreign equipment in terms of chips and amplifier tubes, but the sound is obviously lower. Through my experiments, if the decoding filter chip of your CD player is cs4390, cs8412, cs8414, pcm1732, pmd-100, pmd-200, and the operational amplifier is not lower than opa2604, then your machine will be re-matched with capacitors , The sound will have a huge change, can easily beat the original machine. Below I will take CD as an example to illustrate the selection and matching of capacitors.
In order to match the capacitors in the machine delicately, in addition to having enough high-quality capacitors in your hand, you must also have an important prerequisite, that is, you must have a sufficiently sensitive ear, because in this process, the instrument The help that can be provided is very limited, especially when it comes to film capacitors. Commonly used instruments can hardly play a role. At this time, you rely on your evaluation standards and ears to test the sound. When matching capacitors, fix the large-capacity capacitors first, and then add the small-capacity capacitors separately. At this time, there may be several brands of capacitors for you to choose from at each location. You have no better choice except for patient comparison. After you fix each capacitor, you must do a reverse work, that is, take the small capacitors you added and then take them down in order from small to large, and see if the sound changes, because we have The recombination is done from multiple places, so the modification of the sound may overlap, so this last step is essential. If you remove a capacitor, the sound does not change, it means that your modifications have overlapped, and your modifications in other places can already play the role of the capacitor you removed, so this capacitor can be removed, if The sound becomes worse after removing the capacitor, which means that the capacitor is necessary and the capacitor must be retained. Another thing to remind everyone is that after the capacitor is installed, the sound will change slightly after a period of use. Generally speaking, a capacitor that sounds thick at first will become thinner, and a capacitor with a thin sound will become thicker after a period of use. , So don’t just listen to conclusions after installation, but be patient.
Whether it is designing a device or a motorcycle, we must understand that everything we do is to restore the signal, and our modification is only a last resort when the signal cannot be completely restored. Therefore, you must follow this principle when you mount the machine. The farther away the signal is from the final output terminal, the more you have to consider the restoration problem. At the place closer to the output terminal, the signal has inevitable distortion at this time. And deformation, at this time, you can consider more modification issues.
In the cd, there are three major areas where you need to combine the capacitors. One is the filter capacitor of the power supply part of the turntable, the second is the digital-to-analog conversion and the subsequent operational amplifier filtering part, and the third is the output coupling part. The first part is the farthest from the final signal output, and the third part is the closest. Therefore, in the power supply part of the turntable, try to pay attention to restoration rather than modification. Among the advanced capacitors that can be found at present, the electrolytic capacitor ROE should be the one that modifies the sound the least. Therefore, you can consider using this capacitor instead of rifa and Sibi in this link. We all know that capacitors have a frequency division function. Different capacitance capacitors can better pass signals of different frequencies. Generally, large-capacity capacitors are suitable for low-frequency transmission, and two small-capacity capacitors are suitable for high-frequency transmission. Normal equipment often uses two 3700u capacitors in this piece, and 4700u is also useful. All signals pass through these two capacitors. This leads to smoother low-frequency signals, but high-frequency signals will attenuate, so we need to connect two in parallel. A small high-quality film capacitor provides a direct path for high-frequency signals.
In order to have dedicated channels for signals in each frequency band, the filter capacitors should also be matched with capacitors of different capacitances. For example, select capacitors of the same manufacturer, the same model, the same voltage, and different sizes in parallel. The specific choices are 2200u, 1000u, 680u, 470u, 220u, 100u, and thin film capacitors can be considered for those below 100. However, it is difficult to find such a complete range of ROE capacitors on the market. Therefore, only 2200, 1000, and 470 combinations can be made. Note that two are used for 1000u, so that the capacity of each channel can reach about 5000u. If the capacity is too small , The machine reads the disk badly and will pick the disk. To take care of high-frequency signals. Some high-quality film capacitors must be used. It is recommended to use ero film capacitors. Use 10u, 1u and 0.1u. If you feel the sound is too bright, you can also add a Sibi capacitor with a capacity of 1-2u. The Sibi capacity should not deviate from this capacity Too big. Regardless of whether or not to add Sibi capacitors, the capacitor with the smallest capacity must be ero, which has a great impact on the sound field. In this step, it is also possible to carry out complex matching without so many capacitors. As long as the sound is good, the fewer capacitors, the better.