HOLO Audio Spring 3 Fully Discrete R2R Decoder DAC Direct Solution DSD Pre Power Amplifier，L2/L3 direct solution

Spring 3 is divided into three levels, and the former level can be selected

The power capacitor of L1 is Mundorf's gold and silver oil immersed capacitor. The USB module is a "standard" module without a remote control

The power capacitor of L2 is a customized capacitor, and the USB module is a "standard" module with a remote controller. L2 in the photo

L3 On the basis of L2, the DAC module is selected manually, the USB module is an "enhanced version" module, the transformer is changed into an O-type transformer wound with flat copper, the power cord inside the machine is made of pure silver, and the fuse is also upgraded.

Compared with Spring 2, Spring 3 has made the following improvements

1. The new generation of linear compensation technology better solves the accuracy error caused by resistance, switching elements and PCB, making the equivalent accuracy after compensation reach 0.00005%

2. The new generation of de glitch technology can provide full range de glitch without increasing the noise floor and other adverse effects

3. Based on this new generation of technology, Quan 3 can provide SINAD>110db and dynamic range>127db

4. The PLL+FIFO technology with extreme performance is adopted to provide the ability of restraining Jitter with 0.1Hz and third-order low-pass. High performance femtosecond VCXO is used as PLL clock source. Under the premise of almost immunizing the front end Jitter, it can also lock up up to 1.5us-2us@1KHz Signal with high Jitter of

5. Fully balanced, fully discrete analog front-end amplifier module is optional, providing 84 steps, each step is 1 db volume control

6. The I2S has four independent receiving circuits, which makes the clock signal of the I2S less interfered. In addition, I2S can be configured with line sequence, making it compatible with most HDMI-I2S digital devices on the market

As a discrete resistor network decoder, it is commonly known as R2R. Users may be familiar with the term, but they rarely understand its advantages and disadvantages. R2R uses switch switching of resistor network to convert digital quantity into analog quantity. Compared with the popular delta sigma decoder using high-frequency 0-1 switching, its conversion mode is more pure and direct. Therefore, experienced Singers will know that R2R decoder usually has a natural sound. However, this conversion method is very strict with the accuracy of the resistance network, so to achieve good performance, not only is the cost very expensive, but also the technical requirements are very high. A very small error will cause great distortion. Therefore, for many experienced barbecuers, although the sound of R2R is more natural, it is very vague. It is easy to draw a conclusion that it is difficult to have both. In fact, we can have it both ways, which depends on how we use excellent design to overcome the shortcomings of R2R's lack of accuracy. Although it is difficult, this is our goal. On our flagship decoder "Mei", we used two DAC modules to achieve a SINAD higher than 115 db and a DNR higher than 130 db. Spring 3 used a DAC module like Mei to achieve a SINAD higher than 110 db and a DNR higher than 127 db. You should know that many so-called discrete R2R SINADs still hover around 70-90 db, and the distortion of Quan 3 is less than 10 to 100 times that of these devices.

Spring 3's DAC module has 6 groups of networks on the front and the same 6 groups of networks on the back. A total of 12 groups form a fully balanced structure. Among them, four groups of networks constitute DSD decoding, which we call "vector stepping resistance network", four groups of networks constitute R2R structure for PCM decoding, and four groups of networks are used for linear compensation of R2R network.

Therefore, DSD decoding of Spring 3 does not need to be converted to PCM, but is directly performed by "vector stepping resistor network". This technology was implemented on Quanquan five years ago. At that time, no one could understand such black technology, because conventional R2R could not be used for DSD decoding. This is also the original creation of Quan, and now some other manufacturers have learned from it. However, our algorithm of "vector stepping resistance network" actually has some tricks that are difficult to copy. Basically, except for the inherent noise base of its DSD, no harmonic distortion can be observed. Therefore, those manufacturers who learn from our practices can only copy a shape, but can't copy to God

PCM decoding of Spring 3 is completed by four groups of R2R resistor networks. In addition, there are another 4 groups of resistor networks to compensate the main R2R network linearly. For example, an ideal value is 32768. Due to resistance error, the actual value is 32700. The auxiliary resistance network generates a 68, which is added with the main resistance network to form the ideal value of 32768. Through this technology, we can make the equivalent resistance precision after compensation reach an incredible 0.00005%.

We must know that ready-made resistors cannot achieve 0.00005% accuracy. This is why so many discrete R2R decoders cannot achieve high performance. Because precision determines linearity, and linearity determines harmonic distortion, IMD, and almost all AC performance. This is why the performance of so many discrete R2R decoders measured is only 6xdb, 7xdb, and at most 8xdb. However, PCM1704K can reach 9xdb, because PCM1704K gets higher precision by trimming the resistance with laser. Now Quan 3 can reach 110 db because of the new generation of linear compensation technology. This is the second strongest R2R decoder performance index in the world except Mei.

Spring 3's PLL (Phase Locked Loop) technology comes from Mei. Although this feature has increased the cost, it has significantly improved the sound quality of actual use, so we choose to use this technology on Spring 3, which was originally used only on high-end devices. This PLL is an extreme performance, close to perfect PLL. It provides a 0.1Hz, third-order low-pass jitter suppression capability, and uses femtosecond VCXO as the clock source of PLL. In the test, we analog injected a 1.5us, 1KHz jitter into the digital input. Please note that the unit is us, not ps, ns. 1.5us=150000ns=1500000ps=15000000000fs, which is an exaggerated jitter. In the actual measurement, we can see that it is completely removed. It has no effect on the output.

Quan 3 can optionally be equipped with a fully balanced, fully discrete analog front-end amplifier module. This module can provide 84 level step volume control, each step is 1 db. Generally speaking, the decoder can realize a digital volume control at almost zero cost. However, the performance of the decoder will be greatly affected after the digital volume attenuation is too large. In order to avoid misleading users and using digital volume, we have removed digital volume control from high-end products. The front stage design technology of Quan 3 comes from Spring, which is a very excellent simulation front stage. With this front stage, Quan 3 has an uncompromising volume control function.

In Spring 3, we removed the built-in frequency raising function of Spring 2. Many users reported that because NOS has great advantages in voice, OS features increase costs but are rarely used. It is better to eliminate and reduce costs to make Spring 3 more cost-effective. If you want to use up frequency, it is recommended to use special up frequency software, such as hqplayer. Using the powerful computing resources of the computer to upgrade the frequency will achieve better results than the internal upgrade. If you want to know the characteristics of NOS and OS, you can take a look at this, https://pan.baidu.com/s/1mifMAta

Spring 3's digital input interfaces include USB (ground wire isolation), RCA, BNC, AES, optical fiber, and I2S of HDMI interfaces. All digital input interfaces support DSD (DOP mode). The analog output interfaces of "Spring" are single ended and balanced. The sampling rates of the PCMs and DSDs that it supports are listed in the following table.

Features:

1. The new generation of linear compensation technology better solves the accuracy errors caused by resistance, switching elements and PCB, so that the equivalent accuracy after compensation reaches 0.00005%.

2. A new generation of de-glitch technology, which can provide a full range of de-glitch without increasing the noise floor and other adverse effects.

3. Based on this new generation of technology, "Mei" can provide a SINAD of >115db and a dynamic range of >130db, which represents the performance limit reached by today's advanced R2R architecture DAC

4. Adopting extreme performance PLL+FIFO technology, providing 0.1Hz, 3rd-order low-pass Jitter suppression capability. And use high-performance femtosecond VCXO as the PLL clock source. It can lock signals with high Jitter up to 1.5us-2us@1KHz under the premise of almost immune to front-end Jitter.

5. The power supply adopts an independent chassis, and the power supply of the left and right channels is completely independent to provide better channel separation and sound field positioning.

6.USB and I2S support sampling rates up to DSD1024 and PCM1.536M.

7. The USB interface uses self-developed firmware, with ultra-low latency, highly reliable data transmission, and performance 2-4 times higher than the official firmware.

8. Two groups of independent HDMI-I2S input interfaces are provided, and each group of I2S has four independent receiving circuits, so that the I2S clock signal is subject to lower interference. In addition, each group of I2S can be configured with line sequence, making it compatible with most HDMI-I2S digital devices on the market.

Note: Because the product requires special customization, cancellation without reason is not accepted. The delivery period is 3-4 weeks. Mind please be careful!

the following is buyers feedback and photos shown ，thanks