PowerAnts

The MOSFET of the original poster is external, it is easy to make a sound, but it is difficult to make it well. . . The water is very deep

shaorc

maychang posted on 2019-3-17 14:42 The frequency characteristics of the transformer are quite poor, especially when the frequency range is quite wide. If the ratio of the highest and lowest frequencies is 10 times, then the transformer can...

Thank you [1] The frequency characteristics of the transformer are quite poor. Does it mean that if the frequency range is large, the degree of restoration of the output signal is very poor? And when it comes to flat frequency characteristics, how do you understand this sentence? [2] This kind of constant voltage class D amplifier, without considering the high power amplifier sound quality and noise, can be planned according to the diagram on the 15th floor. The power amplifier chip can be found on the TI website according to the needs (12V power supply input, minimum load 2 ohms, analog input), but for the design of the subsequent buck-boost transformer, are there any recommended reference books or literature?

shaorc

maychang published on 2019-3-17 14:32 "Some audio amplifiers have very good effects (such as subwoofers), while others obviously have very noisy sound quality. This is because the output from the amplifier circuit (push-pull) (positive...

Oh? Am I confusing speakers with modern audio amplifiers? But it feels like there is a very obvious difference in sound quality. For example, the sound quality of a baby's sounding toy is poor, and you can only roughly hear the sound content (such as playing a nursery rhyme), but a good speaker has a strong sense of shock in the bass. Are these two completely different systems? It feels like they are both ABD amplifiers.

shaorc

chunyang posted on 2019-3-17 14:38 The quality of sound involves many aspects, and the final quality also conforms to the "bucket principle", that is, the part with the highest distortion will drag down the entire system. As for impedance matching...

Thank you, I hope you can recommend some Class D amplifier information, especially the constant voltage type, and the design information of the step-up and step-down transformer inside it.

shaorc

PowerAnts posted on 2019-3-18 01:21 The MOSFET external to the OP is easy to make a sound, but it is hard to make it well. . . The water is very deep

It is not an external power tube, but a TI power amplifier integrated chip. The output amplified audio signal passes through a step-up transformer. The step-up transformer design here has not been involved.

maychang

shaorc posted on 2019-3-18 08:39 Thank you [1] The frequency characteristics of the transformer are quite poor. Does it mean that if the frequency range is large, the degree of restoration of the output signal is very poor? And when it comes to the frequency characteristics being flat...

“The frequency characteristics of the transformer are quite poor. Does it mean that if the frequency range is large, the degree of restoration of the output signal is very poor? And when it comes to the frequency characteristics being flat, how do you understand this sentence?” When we say that the frequency characteristics of the transformer are poor, we mainly mean that the frequency characteristics of the transformer are not flat. The frequency characteristic curve of an ideal transformer should be flat.

maychang

shaorc posted on 2019-3-18 08:39 Thank you [1] The frequency characteristics of the transformer are quite poor. Does it mean that if the frequency range is large, the degree of restoration of the output signal is very poor? Speaking of frequency characteristics flat...

"Are there any recommended reference books or literature on the design of the following buck-boost transformer?" You can take a look at this book. 电子变压器设计手册(1993).pdf (9.42 MB, downloads: 7)

2019-3-18 11:26 上传

点击文件名下载附件

maychang

shaorc posted on 2019-3-18 08:39 Thank you [1] The frequency characteristics of the transformer are quite poor. Does it mean that if the frequency range is large, the degree of restoration of the output signal is very poor? Speaking of frequency characteristics flat...

You can also take a look at this book. However, I am afraid that it may seem a bit difficult for you. There is no good way to do this. 电子变压器手册.part1.rar (20 MB, downloads: 14)

2019-3-18 11:31 上传

点击文件名下载附件

电子变压器手册.part2.rar (10.6 MB, downloads: 13)

2019-3-18 11:31 上传

点击文件名下载附件

maychang

shaorc posted on 2019-3-18 08:44 Oh? Did I confuse speakers with modern audio amplifiers? But it feels like there is a clear difference in sound quality, such as the sound of a baby playing...

"Oh? Did I confuse speakers with modern audio amplifiers?" Not really. You just didn't figure out the reason for the "scum".

maychang

shaorc posted on 2019-3-18 08:44 Oh? Am I confusing speakers with modern audio amplifiers? But I feel that there is a very obvious difference in sound quality, such as a baby's sound-making toys...

"But I feel that there is a very obvious difference in sound quality, such as a baby's sound-making toys, the sound quality is poor, and you can only roughly hear the sound content (such as playing a nursery rhyme), but a good speaker has a strong sense of shock in the bass. Are these two completely different systems? I feel that they all belong to the ABD category of amplifiers." To have good sound, from the microphone (converting sound signals into electrical signals), amplification, recording, storage, transmission, reception, amplification, speakers... every link must be good, and one bad one is not acceptable. In fact, the electronic part after receiving is the easiest to do.

maychang

shaorc posted on 2019-3-18 08:45 Thank you, I hope you can recommend some information about Class D amplifiers, especially the constant voltage type, and the design information of the buck-boost transformer inside it

Class D amplifiers, or any other type of modern amplifiers, do not include "buck-boost transformers". Transformers are used only when necessary. Try not to use transformers if you can, and only use them when there is really no other way.

shaorc

maychang posted on 2019-3-18 11:33 "Oh? Did I confuse the loudspeaker with the modern audio amplifier?" Not really. You just didn't figure out the reason for the "scum"...

For the rest, you can read the book you recommended. If you only do the part after receiving, that is, the part after the audio analog signal enters the power amplifier chip, according to what you said on the 30th floor, this part is the easiest part to do well. In this part, what indicators should be considered to see if there is a sound quality problem? I thought it was the impedance matching of the load speaker before, but now I know it is not here.

maychang

shaorc posted on 2019-3-18 13:35 For other information, you can refer to the content in the book you recommended. If you only do the part after receiving, that is, the part after the audio analog signal enters the power amplifier chip, according to your...

"According to what you said on the 30th floor, this part is the easiest part to do well. So in this part, what indicators and parameters should be considered to determine whether there is a sound quality problem or not?" Since you plan to use a ready-made Class D amplifier, it is enough to just choose the output power. As for "impedance matching", as long as your speaker impedance is suitable for your Class D amplifier chip, there will be no problem. By the way: if the speaker impedance meets the requirements of the amplifier chip, this is not "impedance matching".

shaorc

maychang posted on 2019-3-18 14:10 "According to what you said on the 30th floor, this part is the easiest to do well. So in this part, what indicators should be considered mainly to determine whether there will be sound quality problems...

As long as your speaker impedance is suitable for your Class D amplifier chip, there will be no problem. For example, the minimum load of a TPA amplifier chip is given. As long as my load is greater than this value, it is considered suitable? It turns out that this is not impedance matching. I had some misunderstandings before.

maychang

shaorc posted on 2019-3-18 14:37 As long as your speaker impedance is suitable for your Class D amplifier chip, there will be no problem. For example, the minimum load of a TPA amplifier chip is given, and my load...

The power supply used by your amplifier is already given, so the maximum undistorted output power is related to your load. The larger the load impedance, the smaller the maximum undistorted output power. So it is not "as long as my load is greater than this value, it is suitable". Whether it is suitable depends on whether it can meet your output power requirements.

shaorc

maychang posted on 2019-3-18 15:16 The power supply used by your amplifier is already given, so the maximum undistorted output power is related to your load. The larger the load impedance, the higher the maximum undistorted output power...

Thank you

chunyang

shaorc posted on 2019-3-18 08:45 Thank you. I hope you can recommend some information on Class D amplifiers, especially the constant-voltage type, and the design information on the buck-boost transformer in it.

I suggest you look for some books on audio amplifiers first. There are many books on this subject. On the contrary, you should not touch Class D amplifiers first. Many basic concepts must be established first. Don't expect to learn everything at once.

shaorc

chunyang posted on 2019-3-18 16:31 I suggest you look for some books on audio amplifiers first. There are many books on this subject. Class D amplifiers should not be touched first, as many basic concepts need to be understood...

Thank you for your advice. I am looking at it.

shaorc

maychang published on 2019-3-18 15:16 The power supply used by your amplifier is already given, so the maximum undistorted output power is related to your load. The greater the load impedance, the greater the maximum undistorted output power...

Whether the chip mentioned yesterday is suitable, you can check some information about constant voltage amplifiers according to your needs. When it comes to constant voltage amplifiers, they are amplifiers with high voltage and low current output. Domestic constant voltages are commonly used at 120V and 240V. [1] The 120V constant voltage here refers to the effective value of the output audio signal (analog signal). Do we need to first boost the audio signal (which may be only a few volts) output from the TPA series amplifier chip to 1.414*120V through a step-up transformer (audio transformer)? [2] For this type of amplifier, does constant voltage mean that the output voltage is fixed? Or does it mean that the voltage is required to be used as the output to drive the load? Because the output audio signal is an AC sine wave

maychang

shaorc posted on 2019-3-19 13:59 Whether the chip mentioned yesterday is suitable, you can check some information about constant voltage amplifiers according to your needs. Speaking of the characteristics of constant voltage amplifiers...

You said on the 15th floor that "on the train, each carriage has a station announcer, which is equivalent to many speakers in series, plus the transmission line is longer, the output energy of the amplifier will be greatly lost in transmission." Passenger trains have at most a dozen carriages, which cannot be very long. Since it is not very long, there is no need to use 120V or even 240V standards. I have said before: try not to use transformers if possible. The 240V standard is only used for transmission distances of 10 kilometers or 20 kilometers.