In the HIFI circle, the equipment played by enthusiasts is always constantly introducing new ones. However, there is a product called “Direct Digital Power Amplifier” in the category of power amplifiers. Its market share is not high, and it may often be ignored by HIFI enthusiasts who are just getting started. There are relatively few people who really understand it in detail and actually pocket it.
So, such a power amplifier product, what is it “sacred”? Is it an obsolete product? Or a “rookie”? In this issue of audio-visual strategy, let’s talk about “Direct Digital Power Amplifier”.
The difference between “Direct Digital Power Amplifier” and “Digital Power Amplifier”
Is “Direct Digital Power Amplifier” the same as “Digital Power Amplifier”? Or are they just called differently? Many enthusiasts do not know the difference between “Direct Digital Power Amplifier” and “digital power amplifier”. In the previous article, it was introduced that “digital power amplifier” refers to “class D power amplifier”. However, the protagonist “Direct Digital Power Amplifier” in this guide is a completely different type of power amplifier from the “Class D power amplifier/digital power amplifier” explained before.
The reason why the “Direct Digital Power Amplifier” is made into a special article is because it has a special position in the hearts of HIFI enthusiasts, and its market share is not particularly high now, and it belongs to a relatively unpopular power amplifier type. . However, in fact, “Direct Digital Power Amplifier” has its unique characteristics. Whether it is from the perspective of technological innovation or the actual expression of sound, “Direct Digital Power Amplifier” may be a new force in the power amplifier equipment market in the future.
Digital characteristics of “Direct Digital Power Amplifier”
We can roughly know from the name “Direct Digital Power Amplifier” that its inventor wanted to emphasize a feature of this type of power amplifier, that is “digital”. As we all know, the input signal source required by the speaker must be an analog signal, so will the “Direct Digital Power Amplifier” output a digital signal that is not compatible with the speaker at the output end? The answer is no, the output signal of the “Direct Digital Power Amplifier” at the output terminal is still an analog signal. Therefore, the “Direct Digital Power Amplifier” will not have any compatibility problems with the speaker equipment you have now. It is completely the same as other types of power amplifiers in use, and is compatible with all passive speakers on the market.
Analysis of the internal circuit of “Direct Digital Power Amplifier”
Then, a new question arises again. Since the “Direct Digital Power Amplifier” outputs analog signals at the output terminal, why is it called “full digital”? Is it an IQ tax? To answer this question, we need to explain a little bit about some simple technical principles. Of course, this guide is aimed at all audio enthusiasts, and we will try our best to describe the answer to this question in vernacular form.
Regardless of the type of traditional power amplifier, there are generally two input methods at the input end, namely the input of analog signals and the input of digital signals. The biggest difference in the signal amplification process after the 2-way signal is input into the power amplifier is that the digital signal needs an additional DA conversion, which is what we usually call digital-to-analog conversion, which converts the digital signal into an analog signal, and then performs Signal amplification. After the signal is converted into an analog signal, its amplification process is the same as that of the direct input of the analog signal.
We can simply understand that traditional power amplifiers (including Class A, Class AB, and Class D) are actually only amplifying analog signals. They are compatible with digital signal input because DA is added to the power amplifier, that is, the digital-to-analog conversion function. . If you have friends who have more classic models of power amplifiers at home, you must know that 20 years ago, quite a few power amplifiers did not have digital input functions.
The protagonist of this guide, the “Direct Digital Power Amplifier”, is exactly the opposite of the traditional power amplifier mentioned above. If no additional modules are added, the “Direct Digital Power Amplifier” can only amplify the digital signal at the input end. Such features make the “Direct Digital Power Amplifier” very suitable for connecting modern audio equipment. We all know that almost all audio sources are now digital audio sources, including MP3, WMA and lossless formats APE, FLAC and so on. The use of “Direct Digital Power Amplifier” in the home theater system can theoretically simplify the system’s processing of audio signals to the greatest extent, which is very suitable for HIFI players who like to pursue the original sound.
The price of “Direct Digital Power Amplifier”
Next, we will talk about the current consumer market situation of “Direct Digital Power Amplifier” according to the usual practice. There are very few models of “Direct Digital Power Amplifiers” that can be purchased on e-commerce platforms and offline stores. Due to the low popularity, even many audio-visual players do not know that there is such a special type of power amplifier. However, for European and American manufacturers and Japanese manufacturers, every well-known brand generally has at least one “Direct Digital Power Amplifier” on sale, and the price jumps sharply, because each manufacturer cannot accurately position the “Direct Digital Power Amplifier”. Whether it’s high-end or entry-level. Some Japanese manufacturers sell for more than 4,000 yuan, and some European and American manufacturers sell for more than 50,000 yuan. For domestic brands, there are very few “Direct Digital Power Amplifiers” on sale, and they are generally some well-known DIY manufacturers. The price is generally not more than 10,000 yuan, and some are extremely low, within 1,000 yuan.
Of course, the large price span also means that the quality of “Direct Digital Power Amplifier” fluctuates greatly. Different manufacturers and different prices of “Direct Digital Power Amplifiers” will have certain differences in expressiveness. Since there is no integrated DAC chip inside the “Direct Digital Power Amplifier”, the fidelity of the audio signal during the entire “digital-to-analog conversion” process depends entirely on the internal integrated circuit of the power amplifier. This is very different from power amplifier products in other categories. Other types of power amplifier products will purchase dedicated DAC chips. These DAC chips are all from major manufacturers. There are only a few models of DAC chips in the world. Leaving aside the design of peripheral circuits, the quality of the DAC chips It is very guaranteed in itself. Even the most basic DAC chip does not necessarily make the converted sound “unlike”. We can give you an example. When you buy a mobile phone, the included TYPE-C to 3.5MM headphone jack converter integrates the most basic DAC chip inside. Can you “hear” such a cheap DAC chip?
However, such a DAC chip is not integrated inside the “Direct Digital Power Amplifier”. This is its advantage, but also its disadvantage. A “Direct Digital Power Amplifier” with excellent circuit design and luxurious materials can perfectly reflect this advantage. The design architecture without the DAC chip will make the audio processing flow more direct and simpler. The final output sound is also purer. However, if the internal circuit design of a “Direct Digital Power Amplifier” is unreasonable, a “cut corners” manufacturing scheme is adopted. Then, the performance of such a “Direct Digital Power Amplifier” will be relatively poor.
Therefore, if you have relatively high requirements for the final sound quality of the audio system, and you want to try such a “Direct Digital Power Amplifier”, here we still recommend you to buy “Direct Digital Power Amplifier” products designed by major manufacturers and brands.