Accuphase DC-330
￥880,000(Released in November 1999)
Commentary
This digital preamplifier is based on the DC 300 and designed with ease of operation in mind. It has been upgraded to a performance capable of adapting all circuits to new generation digital formats such as SACD by gathering the latest digital technology.
All of the optional slots on the DC 330 allow input of digital signals in new-generation formats such as SACD bit stream output of 2.8224MHz/1bit and 192kHz/24bit. An ultra jitter-free PLL circuit extracts a high-precision reference signal (master clock) from the input signal without distortion or jitter in pulse transmission.
The input signal converted into the internal format of the equipment is converted into an ultrahigh-speed DSP (Digital Signal).
Processor) for digital processing of sound adjustment functions such as tone control, compensator, monophonic and phase switching.
The D/A converter, which affects the sound quality, is electrically separated completely from the digital part composed of DSPs and the analog part after the D/A converter by an ultra-high-speed synchronized digital coupler. After that, digital volume, balance and attenuator processing is carried out, and the signal is converted into analog signal by the newly developed MDS D/A converter.
A third order linear phase analog filter with excellent phase characteristics removes unwanted digital components from the signal converted into analog and outputs it in two balanced / unbalanced systems.
The D/A converter section is equipped with a newly developed MDS (multiple ⊿ Σ) D/A converter that improves performance significantly by connecting multiple ⊿ Σ D/A converters in parallel.
The ⊿ Σ D/A converter is a D/A conversion method that uses oversampling and noise shaping to expand the amplitude information of the input digital signal in the time axis direction to obtain conversion accuracy. In the MDS, a number of such converters are arranged in parallel, the same digital signal is input to each converter, and the output of each converter is added to obtain the overall output.
Since six ⊿ Σ D/A converters are operated in parallel on the DC-330, the overall performance is 2.45 (= √ 6) times higher than that of the converter 1 circuit.
The feature of the MDS system is that performance can be improved at all frequencies and at all signal levels regardless of signal frequency or signal level. Therefore, the MDS system can reduce micro-level noise that surrounds the output signal, which was difficult to eliminate with conventional ⊿ Σ D/A converters.
The volume uses a unique volume control that provides an analog feel.
A disk with radial slits is attached to the shaft of a large knob. When the disk passes through a phase detector, a pulse is generated, and this pulse is input to a microcomputer to adjust the volume.
The volume can be checked by displaying the level value and lighting the LED located around the knob.
A third order linear phase filter with excellent phase characteristics is used as an analog filter to remove image noise in the ultra-high frequency range.
This filter circuit minimizes phase rotation in the passband by optimizing the cutoff frequency, and uses carefully selected elements to improve sound quality.
The D/A converter section uses a printed circuit board made of Teflon (glass cloth fluorine resin).
Teflon has a low dielectric constant (high propagation speed), very low leakage current (low loss), excellent heat resistance and high frequency characteristics. By using this Teflon substrate in audio circuits, purer transmission of signals is possible, further improving the S / N ratio.
The DC 330 also features a gold plate on the copper foil to improve sound quality.
In order to operate the D/A converter in synchronization with the DAI signal, a Phase Locked Loop (PLL) circuit is used to extract the master clock which is the system's reference.
An ultra jitter-free PLL circuit is adopted, and a preamble signal (marker indicating the head of the LR signal) detection circuit and a VCO (Voltage) detection circuit are used.
The master clock extracted by this circuit is not affected by jitter or pulse transmission distortion.
In order to completely separate the digital and analog sections, it uses a high-speed isochronous digital coupler with a transmission capacity of 80 Mbps. The high-speed transmission characteristics allow digital signals to be transmitted to the analog section without noise, contributing to improved sound quality.
Equipped with a high speed DSP tone control and compensator.
Digital processing by DSP can change only the frequency without changing the circuit impedance, enabling sound field control without signal degradation and sound quality change.
When the input selector is turned, the connection terminal of the device is displayed in text on the display. It is equipped with a function to change the name of the input terminal to your preference.
You can change the name to the pre-registered SACD, DVD, CD, MD, etc., or create your own name by combining 8 letters from 96 kinds of letters and symbols.
The analog output consists of a fully balanced circuit floating from ground.
There are two output jacks, one for balanced XLR-type and the other for unbalanced RCA-type.
All the input and recording outputs of the DC 330 are supported by the option board. For this reason, an option slot with a port of the ADB2 interface standard corresponding to the new generation format such as SACD is installed.
The SACD digital output of the DP-100 or DP-85 can be input by adding the HS-Link Input Board and connecting it with the HS-Link cable.
Digital input / output includes optical and coaxial option board (DIO-OC1) as standard, plus additional options for BNC, HPC optical (ST) and HPC balance input.
Analog line input board (AI2-U1) with high precision ⊿ Σ A/D converter corresponding to 96kHz/24bit is equipped as standard.
Equipped with an "EXT DSP Option Board" expansion slot to which the Digital Voice Equalizer DG-28/DG-38 can be connected.
Equipped with an Outputs option board expansion slot for digital volume control by connecting the DF-35 digital channel divider.
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Model Rating
| Type | Digital Preamp | ||||||||||||||||||||||||||||||||||
| Input Format (according to EIAJ CP-1201) |
Quantization : 16-bit to 24-bit line Sampling frequency : 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz (16-24 bit 2 ch PCM each) * Optional board support 176.4 khz, 192 khz (24-bit 2-ch PCM each) 2.8224MHz(1bit 2ch DSD) |
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| Digital Input Format Level (EIAJ CP-1201) |
Format : Digital Audio Interface Optical : optical input -27dBm to -15dBm Coaxial : 0.5Vp-p/75 Ω (depending on option board support) |
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| Digital Output Format Level (EIAJ CP-1201) |
Format : Digital Audio Interface Optical : Light output from -21dBm to -15dBm, emission wavelength 660 nm Coaxial : 0.5Vp-p/75 Ω (depending on option board support) |
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| Frequency Response | 0.5 Hz to 50 kHz + 0 -3dB | ||||||||||||||||||||||||||||||||||
| D/A converter | 24-bit MDS format | ||||||||||||||||||||||||||||||||||
| Total Harmonic Distortion Factor | 0.0006% (20 Hz-20 kHz) | ||||||||||||||||||||||||||||||||||
| S/N | 120dB | ||||||||||||||||||||||||||||||||||
| Dynamic Range | 112 dB (24-bit input, LPF : off) | ||||||||||||||||||||||||||||||||||
| Channel Separation | 108 dB (20 Hz to 20 kHz) | ||||||||||||||||||||||||||||||||||
| Output Voltage / Impedance | Balanced : 5V/50 Ω, balanced XLR type Unbalanced : 5V/50 ohm, RCA phono jack |
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| Volume Control | Speed sensing rotation method Linear mode : - ∞, 0.5 to 99.5 (0.5 steps), Max DB mode : ∞, 94.0 dB to + 12.0 dB |
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| balance control (DSP) | Difference between left and right : ∞, 4 to 0 dB in 1 dB steps | ||||||||||||||||||||||||||||||||||
| Tone Control (DSP) | Bass (315 Hz) + / - 5 dB (50 Hz), 1 dB step Treble (3.15 kHz) : ± 5 dB (20 kHz), 1 dB step |
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| Compensator (DSP) | 1:+3dB(100Hz) 2:+6dB(100Hz) 3 : + 6 dB (100 Hz), + 3 dB (20 kHz) 4:+9dB(100Hz) 5 : + 9 dB at 100 Hz, + 6 dB at 20 kHz |
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| Attenuator (DSP) | -20dB | ||||||||||||||||||||||||||||||||||
| Power Supply | 100 VAC, 50Hz/60Hz | ||||||||||||||||||||||||||||||||||
| Power Consumption | 25W | ||||||||||||||||||||||||||||||||||
| Maximum External Dimensions | 475 mm wide x 150 mm high x 412 mm deep | ||||||||||||||||||||||||||||||||||
| Weight | 20.2kg | ||||||||||||||||||||||||||||||||||
| Attachments | Line Input Board AI2-U1 Digital I/O Board DIO-OC1 Remote Commander RC-24 AC power cord (2m) Audio cable with plug (1m) 75-ohm coaxial cable (DL-15) |
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| Sold Separately : Option Board | |||||||||||||||||||||||||||||||||||
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