Accuphase DP-570S MDS SA-CD Player: An Audiophile Deep Dive

The Accuphase DP-570S MDS is a two channel disc player that reads both SA-CD and CD formats while doubling as a versatile digital hub. It occupies a specific place in the Accuphase catalog: a single chassis machine that combines a robust optical disc mechanism with the company's proprietary conversion architecture and a broad set of external digital inputs. What follows is a detailed look at how the player is built, what each circuit accomplishes, and precisely how you connect it into a system.

What discs can the DP-570S actually play?

The DP-570S plays SA-CD and CD. That means it handles the DSD based Super Audio CD layer as well as standard Red Book 16 bit PCM compact discs, including hybrid discs that carry both. There is no provision for video formats or data files on optical media here; this is a dedicated audio transport and converter. The distinction matters because SACD delivers its content as a high rate one bit DSD stream, while CD arrives as multibit PCM, and the player must manage two fundamentally different data types through its conversion stage. The specified dynamic range figure of 118 dB is quoted specifically for SACD playback, which reflects the wider window that format allows.

How does the MDS conversion system work?

The heart of the DP-570S is Accuphase's MDS, or Multiple Delta Sigma, digital to analog conversion. Rather than relying on a single delta sigma converter chip to reconstruct the analog waveform, the MDS approach operates several converter circuits in parallel and sums their outputs. The engineering benefit is statistical: conversion errors and noise that are random and uncorrelated between individual converters partially cancel when their outputs are combined, while the desired signal adds coherently. The result is a lower effective noise floor and reduced conversion distortion than any one of the constituent converters could achieve alone. This parallel summing is the reason Accuphase can specify a signal to noise ratio of 121 dB and total harmonic distortion of 0.0006 percent, both of which sit at the demanding end of what disc players report.

Why does the frequency response extend to 50 kHz?

The rated frequency response of 0.5 Hz to 50 kHz, at plus zero and minus 3 dB, reflects the extended bandwidth that SACD playback makes possible. Standard CD is bandwidth limited near 20 kHz by its 44.1 kHz sampling rate, but the DSD stream on an SACD carries usable information well above the audible band, and the player's analog output stage is designed to pass it. The low end figure of 0.5 Hz indicates DC coupled or very low corner filtering in the output path, which preserves phase behavior and low frequency integrity. In practical terms, the specification tells you the analog stage does not artificially truncate the signal at either extreme.

Signal Path and Circuitry

What happens after conversion in the analog stage?

Once the MDS circuit produces an analog signal, it passes through an output stage that feeds both balanced and unbalanced outputs. The published distortion of 0.0006 percent and signal to noise ratio of 121 dB are system level figures, meaning they describe the complete path from disc through conversion to the analog output terminals, not the converter in isolation. Interpreting these numbers: a THD of 0.0006 percent means harmonic byproducts sit roughly 104 dB below the fundamental, far beneath the threshold of audibility, and an SNR of 121 dB means the residual noise is effectively inaudible against any realistic listening level. These measurements indicate that neither distortion nor noise from the player should be the limiting factor in a well matched system.

How does the disc mechanism contribute to performance?

The transport is the mechanical foundation that reads the disc and delivers a clean data stream to the conversion stage, and its rigidity and mass are part of why the DP-570S weighs 18.4 kg. A heavy, well braced chassis and drive assembly resist the micro vibrations that can disturb the optical pickup during read operations. While the specification sheet does not itemize the mechanism's construction, the combination of the substantial 18.4 kg weight and modest 18 W power consumption points to a design that spends its mass budget on structural stability and quiet, low current operation rather than on high dissipation electronics.

What does the power supply arrangement tell us?

The DP-570S runs on AC 120 V at 50 or 60 Hz and draws just 18 W. The low power consumption is characteristic of a disc player whose electronics are analog signal circuits and a servo controlled optical drive rather than power hungry amplification. A clean, well regulated supply is essential in a converter of this caliber because any noise on the supply rails can intrude on the sensitive analog output stage and undermine that 121 dB signal to noise figure. The 50 or 60 Hz compatibility means the internal supply tolerates either mains frequency, which is relevant if the unit is used with regenerated or alternative power sources.

Connectivity and System Integration

This is where the DP-570S distinguishes itself from a conventional single box player, because it functions as a full digital preprocessor for external sources in addition to playing discs.

What digital inputs does the DP-570S accept?

The DP-570S provides four digital inputs: HS-LINK, USB Type-B, coaxial, and optical. This selection lets the player act as a standalone digital to analog converter for a range of external sources. The coaxial and optical inputs accept standard S/PDIF digital audio from transports, streamers, and other components. The USB Type-B input is intended for connection to a computer, allowing the machine's MDS conversion stage to process audio delivered over USB. HS-LINK is Accuphase's own proprietary digital interface, designed for high integrity transmission between compatible Accuphase components. Together these four inputs mean the DP-570S can serve as the central converter for an entire digital front end, not just for its own disc mechanism.

What is HS-LINK and why does it appear on both inputs and outputs?

HS-LINK is Accuphase's proprietary digital link, and it appears in the DP-570S as both an input and an output. Its purpose is to move digital audio between Accuphase components over a connection engineered specifically to minimize jitter and transmission errors, using a link topology developed in house rather than relying solely on legacy standards. Because it exists on both the input and output side, the DP-570S can either receive a stream from another HS-LINK equipped Accuphase source or send its own disc data out over HS-LINK to a separate Accuphase converter. That bidirectional presence makes the player flexible: it can be the converter in one configuration or the transport in another.

What analog outputs are available and when should you use each?

The DP-570S offers balanced XLR outputs and unbalanced RCA outputs. The balanced connection carries the signal differentially over three conductors, which allows common mode noise picked up along the cable to be rejected at the receiving component, an advantage over longer runs or in electrically noisy environments. The unbalanced RCA output is the conventional single ended connection compatible with the majority of preamplifiers and integrated amplifiers. Both are provided so the player can integrate with essentially any Accuphase amplifier, and the choice between them should follow the input topology of your amplifier and the character of your interconnects. Neither should be considered a compromise; they simply match different amplifier input designs.

What digital outputs does the player provide?

The digital outputs are HS-LINK, coaxial, and optical. These let the DP-570S function as a pure transport, sending the raw digital data read from a disc to an external converter for processing elsewhere. The coaxial and optical outputs emit standard S/PDIF, while the HS-LINK output offers the proprietary high integrity path to a compatible Accuphase converter. This is a meaningful capability for a system builder: if you later add a separate outboard converter, the DP-570S continues to earn its place by serving as a quality disc transport rather than becoming redundant.

How do the inputs and outputs work together in a real system?

Taken as a whole, the DP-570S has three roles built into one chassis, and its connector set is what enables all three. As a disc player it reads SACD or CD, converts through MDS, and feeds an amplifier by way of the XLR or RCA analog outputs. As a digital to analog converter it accepts an external source on HS-LINK, USB Type-B, coaxial, or optical, and again presents the result on its analog outputs. As a transport it reads a disc and passes the bit stream out through HS-LINK, coaxial, or optical to a downstream converter. Because the same MDS stage and analog output stage serve both the disc mechanism and the external inputs, an external source connected to the coaxial or USB input benefits from the same conversion quality that the disc playback enjoys.

Physical Integration and Interpretation

How much space does the DP-570S require?

The DP-570S measures 465 mm wide, 151 mm high, and 393 mm deep. The width follows the standard Accuphase full size footprint, so it stacks cleanly with matching components, and the 151 mm height accommodates the transport mechanism and the internal shielding and layout separating digital and analog sections. The 393 mm depth is worth noting for rack planning, as you will want clearance behind the unit for the balanced and unbalanced analog cables plus any of the several digital connections in use.

What do the overall measurements suggest about the intended use?

Read together, the specifications describe a machine engineered for transparency and long term system flexibility rather than for a single narrow purpose. The 0.0006 percent distortion and 121 dB signal to noise ratio place its electrical performance among the most capable disc based sources, the 118 dB SACD dynamic range confirms it exploits the high resolution format fully, and the extended 0.5 Hz to 50 kHz response shows the analog stage does not clip the signal at the band edges. The comprehensive input and output complement, with its four digital inputs and three digital outputs alongside both balanced and unbalanced analog outputs, means the DP-570S can anchor a system now and adapt as that system evolves.