"Photographing the poor three generations, HIFI destroyed", believe that everyone can hear this sentence. One mentioned HiFi music, there are about two views. If a type of people think this is a good thing, it is the ultimate enjoyment of the spirit; and the other class will feel that it is a loser. Of course, if you turn a circle in the market, you will find that you will find a few thousand from entry-level HIFI devices to high-end HIFI devices. Most of 10,000 or even dozens, millions, so, want to play HiFi, There are Money to be the first step, and it is also the most important step. In view of this, the author can only silently bring yourself as a type of not touching, not playing. However, recently, I got a coincidence-level HIFI smart digital power amplifier device, which was launched by the positive site atomic team. A D8 intelligent digital amplifier one. Simply look down, the appearance is bright, the price is not expensive, and the ears of my "fungus" are listened, and the sound quality is also a lever (of course, this is also the subjective experience), anyway, it is very good, I will bring it below. Let's learn about this place, see it's true face.
The author gets a complete set of equipment, except for the D8 intelligent digital amplifier, the accessories are also very complete, there are special power adapters, various adapters, and forwarding lines. From the Taobao shop from the positive site, the entire set of D8 devices is also divided into different versions, with the PCM2704 sound card version and the XMOS sound card version, the two differ by 100RMB, as for the difference between the two in performance or function, allow I first sell a Cat, and later introduced it later. And the author's hand is equipped with the XMOS sound card (as a high version of the version), come and see the physical map.
D8 is simple, but beautiful, and the internal accessories are quite rich, especially for music enthusiasts, see so many DIY accessories must be happy, but for the author, "do not swear friends", The resources are limited, the more the accessories, the more it feels violent.
Of course, so many expansion lines above, some of which require additional purchase (such as double lotus head RCA cable, fiber optic line, RCA coaxial, etc.), not included in the entire D8 intelligent digital amplifier unit kit.
The whole D8 smart digital amplifier is moderate, 140mm * 110mm * 32mm, almost one adult slap, the outer casing uses the CNC processing of all-aluminum body, metal brushed, highly textured, giving people the feeling of low-key, very Have high-end flavors, in this era of seeing face, this housing can spike a lot of similar products.
D8 intelligent digital amplifier unit:
Enter: Fiber, Coax, Simulation, USB
Output: Digital amplifier output, ear and output
Sample rate: 44.1kHz ~ 192kHz (fiber, coaxial); 44.1kHz ~ 192kHz (XMOS-USB), 44.1KHz (PCM2704-USB)
Bit: 16 ~ 24bit
Frequency response: 20Hz ~ 20kHz
Rated power: power amplifier output (80W * 2 @ rl = 4Ω); ear and output (2 * 125MW @ rl = 32Ω)
Signal ratio: amplifier (100dB); ear (112dB)
In these, we can find that the first difference between the two different version of the sound card of D8 is supported by 44.1 kHz using the PCM2704-USB sound card, which belongs to the current mainstream CD level sound source, and the XMOS-USB sound card supports higher Quality of the sound source, the highest adoption rate supports up to 192kHz, which is almost the source level of the source, not much in our usual life, so this is not much different.
At the front of D8, a special headphone output jack, a 1.3-inch OLED screen, an infrared receiver, a rotary encoder (for adjusting the volume, and parameter setting).
The back of the D8 smart digital amplifier is equipped with a rich input and output interface, which contains USB input, fiber, and coaxial digital signal input, analog input, and speaker output.
After reading the documentation of D8, it is found that the main features of D8 include pure digital power amplifiers, DAC decoders, and USB sound cards, but it's a bit embarrassing. Because the author is limited, there is no good source input device, no matching speaker output However, there is no way to experience the pure digital power amplifier output of the D8, only a complete audio output consisting of the equipment around the equipment, only the USB sound card input, the headset is output, it feels too fucking, it is really a bit "killing chicken The feeling of the cow knife. " Not much nonsense, first look at the effect of the D8 USB sound card + headphone amplifier output.
The ear-of-the-the-USB sound card is entered into the sound source from the computer music player through the XMOS-USB sound card. After the D8 digital power amplifier, then the headset output, where the music player uses FOOBAR 2000, the headset uses a 3.5mm interface of the CKR10.
While using the XMOS-USB sound card, you will need to install the drive, which can be obtained from the Taobao shop from the positive point atom (also including some test audio and high quality audio, usage manual, etc.).
Install XMOX-USB driver.
Connect the computer, D8, headphones, where the headphones need to be used by a 6.5 mm to 3.5 mm adapter.
However, when it is powered on D8, be careful, the power adapter is connected to the D8 connection, it is easy to mislead short, the best solution is the first power adapter first connection with the D8, plug in the AC socket.
In addition, the player software on the computer and the sound output should also be a corresponding setting, the software's sound driver Select ASIO: XMOS USB Audio2.0 ST 302E.
Set the default playback device, right-click the computer volume icon -. 1882. Set the default broadcast computer XMOS USB Audio.
After everything is ready, you can open the player listening to the song, saying that the effect of the ear is really very good, far more expected. I did not think that the sound of XMOS-USB sound card is so purely, the sound level is clear, and it is completely comparable to a general HIFI player, spike the so-called HIFI music phone.
D8 is also in place, through the waveform and spectrum display, make music very dynamic.
Various menus settings, such as display, equalizer, source selection, EQ settings, bass effects, treble effects, etc.
There is also a particularly like function D8 supports automatic switching machine. For example, when you connect the device by default, as long as you detect a certain intensity audio signal input in D8, D8 can automatically boot, and if it is 15 minutes If there is no operation, D8 can automatically power saving, and both functions can be selected separately or off separately. More functions about D8 will not be described in this article. Compared with the power amplifier on the market, the advantages of D8 are still very much, and they can refer to the table below.
After experiencing the D8's ear, this product has conquered me. It is not ideal for most computer sound card sound quality or some computer direct headphones, and the bottom noise is large, and the resistance of the resistance headphones is more difficult. Situation, D8 is definitely a good product to solve these problems. However, I like to take the computer to learn / work, listen to friends, or stay away from D8, I am afraid that you have no thought or work.
Dismantle
Experieving a D8's ear effect, it is indeed a long-term expected feeling, and the author is extremely curious about the construction of D8, so I can't help but explore. D8 uses the front and rear panels to draw a drawer structure, screw the screws of the two panels can be easily extracted from the back.
The front panel is an OLED screen and an infrared receiver circuit.
Whether it is the outer shell or internal board, work is very high quality.
To see the resources on the lower board, the main devices are distributed on the front, the circuit layout is clear, the adopted components used on board cards are very high quality, and they are not vague, such as ELNA-specific audio coupling. Capacitance, ultra-low ESR black diamond solid capacitor, MMT digital amplifier dedicated solid state capacitors, etc., it is really spent.
Specifically, it is understood that there are several chip functions on the next board. PCM5122 is a top DAC converter launched by Texas, with 112dB signal-to-noise ratio and 0.003% Total harmonic distortion, up to 384kHz, 32bit audio playback It is definitely a professional audio decoding chip that is mainly used in D8 for the conversion of digital signals.
The WM8805 is a digital receiving chip that receives digital signals from XMOS asynchronous USB transfer, with ultra-low Jitter, supports 193kHz / 24bit signals, and performance beyond CS8416, Dir9001 and other chips.
AK5358 is a stereo A / D converter of AKM, sampling frequency range 8 kHz ~ 96kHz, with 102DB signal-to-noise ratio (this ADC chip in the Broadlink WiFi speaker), D8 digital amplifier all-in-one is equipped with this chip Or add different audio input interfaces to make D8 apply to more music playback devices, compatibility is stronger.
The MAX9722 is the AB-class ear-up chip introduced by Weicin. It has a signal-to-noise ratio of 112dB. It can provide 125MW drive capability for 32Ω headphones. It can push 600Ω high-impedance-resistant headphones, mainly in some music players, of course, in some main sound quality It will also have its figure in high-end phones.
The back surface of the D8 board is mainly the pure digital power amplifier chip of the ST and is equipped with a heat dissipation aluminum sheet.
STA328 is a digital audio dedicated amplifier chip introduced by ST, using DDX technology, and three-state modulation has lower EMI, higher efficiency, better PSRR and SNR than ordinary D, and integrates Sound Terminal technology, all numbers. Signal processing, no AD conversion, improves the signal-to-noise ratio, can compensate the output to the output, with better linear, more pure sound, and better analytical force.
Finally, let's take a look at the prices of the two USB sound cards of the article, "selling a joint", and XMOS and PCM2704, while XMOS is worth 100RMB, why?
The reason is still in technology. If you go to the market, you will find the current USB decoder or very popular, such as the two USB sound card schemes adopted by D8, using the signal from the PCM2704 is generated using the internal phase lock ring, It is jitter, as an audio system, if the source is not good, how to optimize it is endless. The USB asynchronous transmission scheme of the XMOS chip is different. It does not use the internal phase lock ring, and the switching of different frequencies is provided by different crystals, so we can also see multiple crystals on the D8 XMOS-USB sound card. . In addition, as mentioned earlier, compared to PCM2704, XMOS supports higher sampling rate, and friends who decode the USB sound card decoding have demand, they may consider the D8 products of the XMOS-USB sound card. Finally, dismantle the complete D8 smart digital amplifier, the author also draws a brief hardware principle block diagram for reference only.
Finally, the D8 smart digital amplifier is a rare domestic good product, powerful, combined digital power amplifier, DAC decoder, USB sound card as one, for friends who like HiFi, but not too rich, Value for money, like friends may wish to start, will not let you down.
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