Accuphase DC-330 Brochure

PRECISION DIGITAL PREAMPLIFIER

DC-330

m Fully digital preamplifier with ultra high-speed digital signal processing m Ready for new-generation formats such as SACD and DVD-Audio m Newly developed MDS type D/A converter minimizes distortion and

assures outstanding S/N ratio m High-precision tone controls and loudness compensation implemented in the digital domain m Volume control with familiar analog feeling m Ultr a jitter-free PLL circuit topology

Leaving the analog/digital division far behind  this digital preamplifier features ultra high-speed DSP and complete readiness for the new generation of super high quality audio sources. The newly developed MDS (Multiple Delta Sigma) converter with 24-bit ultra high precision resolution results in dramatically enhanced performance. Witness a new dimension of audio perfection.

The DC-330 builds on the foundation of the DC-300, with some significant advantages over its predecessor. Ease of use has been further enhanced, and latest digital technology and redesigned circuitry assure total compatibility with the emerging new generation of top-quality audio sources such as SACD and DVD-Audio. The digital volume and tone controls function with previously unattainable precision, yet their smooth operation feel is on a par with the best of analog equipment. Internally, the DC-330 features ultra high-speed digital processing performed by a latest-generation DSP device. D/A conversion is handled by an inno vative MDS (Multiple Delta Sigma) converter which boasts superior accuracy. This makes the DC-330 capable of bringing out the full potential of a new breed of audio sources that is just emerging, such as the Super Audio CD (SACD) and DVD-A udio. During the dev elopment of this amplifier, countless listening sessions were held to arrive at the detailed, rich sound that is a hallmark of every Accuphase product. In a preamplifier, the part that has a decisive influence on the sonic end result is the section where adjustments such as volume, tone, and loudness compensation are carried out. In the digital DC-330, this task is handled by an extremely fast DSP that assures a drastic leap in performance, achieving outstanding signal-to-noise ratio, amazing channel separation, and totally negligible distortion. The overall result is utterly natural and realistic sound with full control over every vital aspect. To provide complete flexibility with a view to future expansion, all inputs and recording

Left

Option Slot 8

Analog Input

Right

AI2-U1

Option Slot 7

Digital Input/Output DIO-OC1

Option Slot 6

Option Slot 1

External DSP

Option

(

DIO-OC1

Volume Control Outputs

Option

(

DIO-OC1

24-bit A/D Converter

Coax

Opto

Coax

Opto

Coax

)

Opto

Coax

Opto

)

Volume

DAI

Decoder

Volume

Information

outputs of the DC-330 are implemented as option boards. The option board slots support the ADB2 (Accuphase Digital Bus 2) interface which accommodates also formats such as SACD and DVD-A udio . The DC-330 comes with a line input board for analog signals and a digital input/output board installed as standard equipment. As a perfect blend of analog operation feeling and sophisticated digital technology, the DC-330 transcends the mechanistic division of “analog” or “digital”, fusing them both into a higher dimension that is devoted solely to the enjoyment of music.

Fully digital preamplifier with ultra high-speed DSP and support for high sampling rates: 2.8224 MHz/1-bit and 192 kHz/24-bit.

Figure 1 shows the block diagr am of the DC-330. Digital sources are connected via coaxial or optical inputs located on option boards. All option board slots of the unit are ready to handle the bit stream output of a SACD player which uses 2.8224 MHz/1-bit, as well as the 192 kHz/ 24-bit signal used for DVD-Audio. Other high-quality formats that may emerge will also pose no problem to the DC-330. After the input, an ultra jitter-free PLL circuit extracts a high-precision reference signal totally free from the adverse

Digital Isolator

DSP

Tone

Comp

Mono

Phase

Ultra

Jitter-Free

PLL

Master

Clock

Digital Isolator

DAI

Encoder

Fig. 1 DC-330 block diagram

MDS 24-bit D/A Converter ×6

∆Σ

Digital Filter

Volume Balance

Attenuator

MDS 24-bit D/A Converter ×6

∆Σ

Digital Filter

Volume Balance

Attenuator

3-Pole Linear Phase

Low Pass

Filter

Balanced Buffer

3-Pole Linear Phase

Low Pass

Filter

Balanced Buffer

effects of pulse transmission distortion and jitter. After conversion into the internal format of the DC-330, a DSP (Digital Signal Processor) operating at extremely high speed performs some of the major tasks that are handled by a preamplifier, such as tone control, loudness compensation, as well as mono and phase switching. All of

Ultra high-speed DSP

these adjustments are accomplished entirely in the digital domain. An ultra high-speed “isolated digital coupler” ensures effective electrical separation between the digital section encompassing the DSP and the D/A converter and subsequent analog segments of the amplifier. After digital volume, balance, and attenuation processing, the signal reaches the newly developed MDS type D/A converter which produces an analog signal of utmost precision. A 3-pole linear phase low-pass filter then removes any remnants of the digital process, before sending the signal to the balanced and unbalanced outputs.

Innovative MDS (Multiple Delta Sigma) converter reduces distortion to theoretical limits and assures outstanding S/N ratio

The D/A converter which has considerable bearing on the sonic end result is a newly

developed type that provides excellent performance in all aspects. The MDS (Multiple Delta Sigma)

Unbalanced

Outputs

Left Analog Outputs

principle employs sev eral delta sigma type converters in a parallel configuration which results in a drastic precision enhancement. The delta sigma principle combines oversampling with noise-shaping (a kind of digital feedback) which projects the amplitude information of the digital signal onto a time axis for precise conversion. Figure 2 shows

Balanced

Outputs

several delta sigma con verters which are fed with the same signal and whose outputs are combined to arrive

Unbalanced

Outputs

Right Analog Outputs

at the overall waveform. In the DC-330, six delta sigma converters are operated in parallel, which results in a performance

Balanced

Outputs

improvement by a factor of

2.45 (=√6). An important characteristic of the MDS principle is that the performance benefits are achieved regardless of signal

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