In the Hi-End decoder market, there are strong competitors, dCS, Esoteric, MSB, emm Labs, Soulution, Orpheus, Wiess... Each leader is in the limelight, and no one dares to pat his chest and say that he is the first. But after trying out the Alpha DAC Reference Series 3 decoder launched by Berkeley Audio Design in the United States, I suddenly had an impulse in my heart to leave it behind.
At the end of the last century, the HDCD format developed by Pacific Microsonics in the United States competed with SACD for supremacy in high-definition digital music. For a variety of reasons, the SACD won, but Pacific Microsonics' Model One and Model Two DACs and ADC are still considered to be the best professional-grade equipment for sound quality today. Berkeley Audio Design was co-founded by Michael Pflaumer and Michael Ritter, who is responsible for all digital algorithms and Michael Ritter specializes in analog circuits. During the development of the Model One and Model Two, they discovered that digital music can also be very delicate, lighthearted and realistic, especially through the recordings made by the Model Two in 24Bit/176.4kHz and 192kHz formats. The sound was so natural that it was barely different from listening to an instrument in the field, so they launched the Alpha DAC with the aim of getting what was originally limited to the professional realm of sound to get out of the studio and onto the audiophile's favorite list.
The standalone Alpha USB interface conversion, which topped the charts in Computer Audiophile magazine with a top score of 110, claimed that digital output surpassed the dCS Scarlatti turntable, and also beat high-priced interface converters such as dCS U-Clock and Swiss Soulus 590
The HDCD format was invented by Keith O. Johnson and Michael Pflaumer, and although it was developed in the late 1980s, commercial CD records that were actually processed with HDCD were not available until 1995. HDCD encoding can really improve the sound effect a lot, but the decoder must have built-in HDCD decoding (which requires additional cost of licensing), which makes HDCD only exist in the Hi-End audio circle and cannot be widely used. Keith O. Johnson is a very famous sound recordist, he recorded RR records with excellent sound, riding his ride, RR CD records have been processed in HDCD, so that this format is barely preserved. In 2000, the HDCD patent right was acquired by Microsoft Microsoft, and then Microsoft quietly built an HDCD decoding algorithm (Version 9) on its own Windows Media Player (referred to as WMP), as long as the home computer meets:
(1) Turn on the 24Bit sound settings
(2) The sound card supports 24Bit processing
(3) Playing a real HDCD record
The chassis is excavated with CNC using a 6061-T6 whole aluminum blank, which has excellent strength and corrosion resistance, and the entire enclosure is very strong and can well suppress internal and external vibrations
If you meet the standard, you can enjoy the full sound quality of HDCD. Play hdCD records with WMP11 or WMP12, and then grab track records, you can find that the cd effective Bit depth is 16 Bits, while HDCD is 20 Bits, which is 4 bits of data. We know that the sampling frequency determines the sound and audio width, and the Bit depth determines the dynamics, and 4 more Bits make the dynamic upper limit from the original 96dB to nearly 120dB (theoretical value). Judging from the waveform graph, the peak part of the CD track looks like it has been compressed, and the HDCD is more natural, and the instantaneous sound pressure even has a gap of nearly 3dB. In order to better retain the peak, HDCD leaves 1 Bit (6dB) of space, so that the recording engineer does not have to worry about level overload, so after turning on the 24Bit sound effect, the output of WMP will be reduced by 6dB to leave HDCD decoding margin. After the dynamic range is extended, HDCD retains a weak information of -100dB, including the noise of the recording equipment, the spatial details of the recording scene, etc., which have a great impact on the continuity, density, texture, and sense of space of the overall listening. However, the CD format is 16Bit, and the real force has not been caught, so HDCD will find a way to hide the encoding where CDDA cannot be used, and then restore it to a 20Bit signal when decoding. In addition, HDCD also uses Dietering and filtering and other functions, and many parameters can be adjusted, so that the recording engineer or mixer can control according to the needs, and improve the final CD product.
The all-aluminum remote control can control functions including absolute phase, left and right balance, etc
Unfortunately, the CD player with HDCD decoding is gone, and finally even the decoder is rare. In addition to being the inventor of HDCD and the owner of RR Records, Keith O. Johnson also designed equipment for Spectrum, an American Hi-End sound company. Spectral launched the first SDR-1000 in 1987, claiming to be the first truly Hi-End CD player in the United States, and then after years of brewing and design, it launched the SDR-4000, and finally changed to SDR-4000SV. The CD machine created by the inventor of HDCD should be able to perfectly explore the advantages of the HDCD format. As emm Labs' Ed Meitner (one of the inventors of the DSD format) launched its own SACD dial + decoder. Spectral is not called CD Player, but by CD Processor, which is evident in confidence. The first generation of SDR-4000 using TEAC's VRDS dial, to the SDR-4000SV to switch to CD-ROM, or even without balanced analog output, and the use of Analog Devices' unique multi-BitΣ-Δ chip AD1853, also only support 24Bit/192kHz, is really a bit out of step with the times. Is HDCD really silent?
A professional model, the Alpha DAC Reference Series 3 has only a standard 75 ohm impedance BNC connector with a coaxial input
No! Berkeley Audio Design debuted with alpha DAC Reference Series 3, and if nothing else, if you want to decode HDCD, it's definitely the only king today! The company's first Alpha DAC was introduced in 2008, followed by the Alpha DAC Reference in 2014, and over the years, the machine has undergone several upgrades, including better filtering (via software updates), the addition of MQA extended decoding, and other improvements. The latest Series 3 is the biggest upgrade, including replacing ceramic circuit boards and very low phase distortion clocks. Worthy of the practice of professional products, Alpha DAC Reference can be paid for each generation of upgrades, some need to send the machine back to the original factory, and some only need software operations (such as MQA decoding), ensuring that it will not be obsolete for a long time. Since each new product requires designer Michael Pflaumer to spend hours manually calibrating and listening, this is doomed to be unable to mass-produce, and often even out of stock for months.
The Alpha USB interface converts a USB interface that can be connected to a computer or digital dial into a BNC coaxial or AES/EBU balanced output
Although there is no chance to compare the previous generation of Series 2, compared with several decoders on hand, including music faxes Musical Fidelity M6Sr, Vibrato NDP, Pureaudio AirDSD Pro, etc., Alpha DAC Reference Series 3 can be said to be completely rolled. It has greater dynamic undulations, more dynamic rhythms, more compact bass, clearer graphics and richer layering. The sudden burst of energy of the small drum in orchestral music is vivid, open and realistic, and the pressure of the large tone does not increase the brightness or auditory fatigue at all. It's the perfect combination of high resolution and low noise, the Alpha DAC cleverly presents musical detail in an imperceptible way, the instrument has a high sense of density and weight, the soundstage level is well-structured, and the sound tone is just as pure as the spatial depiction. Playing an HDCD demo disc with RR records, alpha DAC's ability to dig deep into the faintest details creates a huge sense of space, the air flow around the instrument seems to be visible, and the dynamic expression at low volumes is clearly retained, with the relaxed effect of using high-power rear stages. At high volumes, the Alpha DAC is completely devoid of ostentatiousness and graininess, and the transients come suddenly and powerfully, but there is no sense of stimulation accompanied by a strong sense of impact, because its background is as quiet as crystal glass or the blue sky on the plateau, and all the melodies clearly float between the two speakers, without impurities and without cover-up. The reference equipment sounds as if the bass is missing some of the detail due to the noise floor, which makes the instrument less vivid and realistic, the soundstage is less spacious, the resulting knot positioning is blurred, and the air flow around the instrument and vocals is less obvious.
Alpha DAC's specially customized ultra-high precision thermostatic clock minimizes jitter
The atmospheric sound of alpha DAC Reference Series 3 is related to the high output level, the balanced output is as high as 6.15V (+18dBu), and the unbalanced output is also 3.25V (+12dBu), which is much higher than the standard 4V/2V, so it can be used as a front-level direct drive rear-stage amplifier. The front part is not sloppy at all, the digital volume control is 0.1dB per level, the left and right balance adjustments are 0.05dB per level, the volume is a total of 60dB range, basically I put the volume in the maximum 60dB position. In the event of an unexpected power failure, the volume output level will return to 25dB, and the volume can be readjusted with the remote control after turning on. The operation is very simple, after connecting, the alpha DAC that detects the digital signal will automatically lock, and the phase can be selected through the panel button (for example, some Teresa Teresa recordings are inverted, and the image and positioning of the vocal instrument after adjustment are more condensed and accurate) and output levels. On the right side of the panel, select Stereo, Left, Right and Sampling Frequencies (up to 384kHz eight times 48kHz). There are four digital filtering options, with the smallest phase deviation and pre-bell ringing in 2.16 and 2.24 modes, and the extension and roundness of the high-frequency part will change when switching. The factory recommends using a preset 1.16 or 1.24 filter mode when playing CDs, that is, the PMD-100 and PMD-200 filters that simulate Pacific Microsonics, and I myself prefer the 1.24 filter mode (24 for 24Bit).
The motherboard of the Alpha DAC Reference Series 3 is made of ceramic, which, in addition to its high insulation, has excellent heat resistance, helps to suppress noise and avoid equipment heat, and helps to improve sound quality
The casing excavated from CNC with a whole piece of aviation aluminum is absolutely heavyweight, with excellent electrical and mechanical noise isolation and extreme stability, which is one of the true secrets of the reference Series 3 sound. The Greek letter Alpha on the top plate is oxidized to black, which contrasts with the natural aluminum color of the chassis and is very beautiful. In addition to heavy armored chassis isolation and independent shielding of power supplies, the Reference Series 3 also uses ceramic circuit board materials. Ordinary PCB is made of copper foil and substrate bonding, most of the substrate materials are glass fiber (FR-4), phenolic resin (FR-3) and other materials, the processing process is affected by thermal stress, chemical factors, improper production processes and other reasons, may occur to varying degrees of warpage and interference. Ceramic substrate is widely used in aerospace, military electronics and other products, the biggest advantage and is the largest ampacity, 100A current continuously through 1mm/0.3mm thick copper body, temperature rise of about 17 °C; 100A current continuously through 2mm/0.3mm thick copper, temperature rise is only about 5 °C; there is better heat dissipation performance, low thermal expansion coefficient and good insulation, and high pressure resistance, high reliability, high performance and stability. The disadvantage is that it is fragile, it is impossible to manufacture large-area circuit boards, and it is expensive, and it is impossible for low- and medium-end products to use.
At the heart of the decoder is the DAC chip, and Berkeley Audio has never announced which company's chip they use, saying only multi-BitΣ-Δ technology. RR record recordist Keith O. Johnson also designed audio equipment for Spectrum, which uses Analog Devices decoding chips in CD players, so I guess the same is true for Alpha DACs. But Berkeley Audio says they only use the DAC core, turn off all the other functions built into the chip, have no digital filtering, and have no upconder processing, which are implemented in an external DSP by their own software. Because there is no other processing in the chip other than D→A conversion, the current bounce on the substrate is minimized, which greatly improves the conversion accuracy, which is better than using a complex FPGA design.
Each circuit board inside is separated independently, the power supply part is isolated and shielded, and various measures are taken to prevent interference between modules. Alpha DAC has never announced the DAC decoding chip used, and the guess is that it is a relatively rare Analog-Devices chip, because Spectrum's CD machine also uses ADI chips, but Berkeley Audio said that they only use the core part of decoding, and the rest such as reception, digital filtering, etc. are developed by themselves
As for DSD decoding, Alpha DAC has another idea that it does not support DoP or so-called DSD native decoding. In fact, DSD decoding technology has existed for many years, and there is a Pure DSD channel inside the DAC at the CS4398, DSD179x, which is not a new technology. However, the digital broadcast in previous years did not support DSD, even if it supported DSD, it did not use its native DSD channel, in fact, it still converted DSD into PCM and then decoded inside the DAC. The sampling frequency of SACD is 2.8224MHz, while the frequency transmitted by DoP is 176.4kHz, plus the actual valid data 16Bit (a total of 24Bit, but the high 8Bit is the mark information of DoP), 176.4kHz x16 = 2.8224MHz, theoretically exactly the same, but the sound decoded by the DSD on the sound is more sleek and smooth, while the dynamic of PCM decoding is larger. Berkeley Audio believes that converting a DSD from one bit to multiple bits is the worst way to do it at the same time as decoding on a single chip. So they use a separate DSP processor, their own algorithm to perform multi-bit conversion, decoded in the DAC chip, which not only improves the accuracy but also reduces the noise. The factory also recommends that if you are playing music on the computer, you may wish to use software such as JRiver Media Center to convert the DSD into a 176.4 kHz/24Bit AIFF or WAV file in advance, and then give it to Alpha DAC for decoding, which can have better results.
The linear power supply, which is completely isolated from the motherboard, is equipped with two large EI transformers for digital and analog power, respectively, for low noise and low distortion power supply
Play hdCD-encoded discs (or HRx HD music files from RR records), the panel's HDCD light will light up; the playback MQA disc panel will have no indicator light, but the screen will display the words MQA (too simple to understand) and the expanded sampling frequency. Due to the limitation of bnc coaxial and AES/EBU balanced interface, only 24Bit/192kHz digital signals can be transmitted, so Alpha DAC cannot support higher format decoding. Once chatted with recording engineer Leo Feng Weiguo, he said that the best high-definition digital format is 24Bit/192kHz, 24Bit/384kHz and other high-definition formats are too clear, too much detail, but there is a "digital taste" feeling, Berkeley Audio does not use any upscaling technology, probably experts see the same. At the same time, the Alpha DAC has no USB or Ethernet connection (firmware upgrades cannot be connected to the network, and need to be burned to a CD before proceeding), because doing so will connect the ground of the decoder to the ground of the computer or music server, and it will not be able to completely isolate RF noise, which is the focus of berkeley Audio designers. To this end, they designed a split Alpha USB interface converter that converts the USB input to BNC coaxial and AES/EBU balanced outputs.
The Alpha USB is housed in a smaller iron enclosure, the panel has only one indicator light, appears green when connected to the USB, and like the Alpha DAC, there is no power switch to stay powered on for optimal performance. Berkeley Audio uses BNC coaxial because it is the 75 ohm standard for S/PDIF, the general RCA connector is 50 ohms, and BNC is more stable. If a computer is connected, an Apple computer running Snow Leopard or a later operating system can automatically connect to Alpha USB, and Windows users will need to install driver software. USB was originally designed to connect computer peripherals, but now it has become the universal standard for the transfer of high-definition music files or DSD files for audiophile audio, and although the latest USB 3.1 Gen2 can achieve theoretical speeds of up to 10Gbps, which is 20 times the maximum theoretical speed of 480Mbps of USB 2.0, it does not help audiophile audio. The USB pin includes a voltage of 5V, and the USB packet format is very similar to the early Internet packet format, the data is discrete and repackaged separately, which is significantly different from the continuous bitstream digital audio format of S/PDIF. So even if we have used a 10,000 yuan USB cable to connect Alpha USB with high-end players such as Aurender W20, the problem of USB inherent still exists.
The DAC can decode HDCD and has four sets of digital filters to choose from, including PMD-100 and PMD-200 filters from analog Pacific Microsonics
Alpha USB is done by completely isolating the contaminated USB circuitry, and the USB input jack is mounted on a plastic plug-in to separate it from the chassis to prevent noise coupling between capacitors. Separate linear power supplies power the clock and digital audio outputs, respectively, and asynchronous reception indicates that alpha USB's output does not utilize the computer's or player's clock. Alpha USB has two sets of ultra-low phase noise oscillators built in, one for the 44.1kHz series sampling frequencies (44.1kHz, 88.2kHz and 176.4kHz) and the other for the 48kHz series (48kHz, 96kHz, 192kHz). The original factory recommended that when using Alpha USB, it should not be placed on top of the decoder, at least 0.5 meters away from the audio cable of other analog signals, to physically isolate the "dirty and noisy" USB cable. Conditional limitations I can not test Alpha USB alone, foreign reports take it with the computer in the Lynx AES16 professional sound card AES / EBU output, play RR record 176.4kHz / 24Bit HRx HD file, think that Alpha USB can be higher resolution and musical expressions. In particular, the sense of space and the natural sense of the stage, it brings a deeper sense of stage, the sound field is more backward, and the contour portrayal of the rear instruments is more obvious. Bass has clear details, the instruments become clearer, and the treble is more lively, with density and delicate texture at the same time. Finally, Alpha USB has a better sense of ease in the bursting climax, the melody sounds more elegantly in the complex symphony, and the overall sound is smooth and smooth.
The Alpha DAC is primarily used by studios and is standard equipment in many studios, and the Pacific Microsonics professional HDCD decoder Model 2 is known for its excellent sound quality, which was developed on the basis of the Model 2
When I auditioned, I mainly connected the EMT 986R broadcast-grade CD player (connected by AES/EBU), and the Vibrato NMT digital player (usb connected to Alpha USB), which required an extra power cable and a balanced digital cable, although it was an additional overhead, it was worth the price of sound. EMT 986R itself can play WAV files in the mobile hard disk, the sound performance is accurate and rigorous and pragmatic, the high and high three-stage balance does not have any prominence, the low-frequency bounce force is excellent tension and easy to retract, the level of the sound field and the positioning of the instrument are very good, but the bias towards rationality is less intimate and infectious. Wenjie Vibrato NMT digital player and the supporting NDP decoding pre-stage are also connected by USB, the sound is clear and bright, the sound quality is crisp and the texture is meticulous, the subtle dynamics and control are excellent, the two ends are flat and straight, and it is also close to the monitoring style of the product.
Although HDCD lost to the later SACD in terms of commercial development, American RR records still add HDCD encoding to CD discs, and with the Alpha DAC Reference Series 3 decoder, THE CD that plays RR can get a greater dynamic effect of 20Bit
After connecting the Berkeley Audio Design Alpha DAC Reference Series 3 decoder, the two sets of reference machines have been improved to varying degrees, especially the EMT 986R CD machine, which can be said to be a qualitative leap. Still in terms of the demonstration disc of RR records, Alpha DAC not only has a wide and open feeling of 180-inch large screen, the transparency, purity and detail expression ability of the sound, there are almost no opponents, the key is that it is very natural and vivid, without any trace of axe chiseling. The benefits of ultra-low noise are everywhere, with the second track Arthur Wills' "The Vikings" being performed by the Dallas Wind Ensemble, and the overwhelming sound of the pipe organs is shocking enough, and the Alpha DAC also depicts a huge concert hall space, with the orchestra arranged on stage, wide, deep, tall and full of atmosphere, all the details combined to form the effect of a real live performance. The eighth track "Dooji Wooji" and the ninth track Artie Shaw's flute concerto, the jazz rhythm is clear and jumpy, the Reference 3 has a strong and strong bass, the instant burst of energy is full of energy, you will almost involuntarily step on the feet and beat the drum. It's an engaging sound that makes people intoxicated.
Compared with the reference machine, the Alpha DAC has a sense of presence closer to live performance, rather than simply enjoying canned music, and its dynamics are closer to real instruments. Some of the equipment is also analytically powerful, but it sounds dry and tasteless, lacks the relaxed feeling of calmness, and cannot portray an accurate and huge spatial effect. In the past, I always thought that it was easier to distinguish the differences in the performance between different concert halls through the multi-channel system, but now through alpha DAC, I can actually appreciate the differences between the Cincinnati Symphony Hall and the Meyerson Symphony Center in Dallas, which takes us to the best position in the concert hall and hear a clear sense of stage space, with a vast and deep sound field, uncompressed dynamic undulations, and a dense and meticulous texture! The damn thing is that Alpha DAC is not as masculine and tough as some professional equipment, it can be very delicate and delicate, it can be very soft and warm, it can also be very lively and fast, how can people not love it!