●HPC digital transmission system for high-quality transmission ● New MMB type D/A conversion system ensuring 20-bit resolution linearity and low noise ● Automatic detection of three sampling frequencies and three frequency accuracy levels
High-quality transmission – HPC optical and HPC balanced digital outputs are provided to implement ideal digital signal transmission
Rioid heavyweight structure with 8mm thick solid aluminum chassis Auto-lock mechanism that frees the CD transporter from harmful resonances
150M BPS. The supplied optical fiber cable for
d XLR type connectors is supplied. The balanced principle offers similar advantages as
Ultimate in multibit configuration — Implements theoretical-limit performance as high as 20 bits with the newly developed MMB D/A conversion system.
Equipped with HPC digital inputs for high-quality digital signal transmission. Handles three different sampling frequencies and automatically detects three frequency accuracy levels.
Newly Developed MMB Principle Yields 20 bit Linearity and Minimum Noise
The D/A converter design is an essential criteria for sound quality. The DC-91 positively excels in this regard, thanks to its newly developed MMB converter system. The acronym MMB stands for "Multiple Multi-Bit" and refers to sixteen strictly selected 20-bit D/A converter elements which are connected in parallel. The improvement yielded by the parallel connecion is exemplified by the fact that connecting on elements in parallel will yield twice the current but distortion and residual noise will noise will in terms of signal versus noise in this case is 3 dB. With several elements in parallel, the improvement can be calculated according to the following equation, where "n" is the number of parallel elements:
20 log (1/√n) [d]
Since the DC-91 uses sixteen elements, the provement is 12 dB.
As can be seen from the graph, response of digital ioput versus analog output is absolutely linear forovery high to extremely low levels. Detortion and noise are also virtually absent, so that the converter attains the theoretical limits of performance. And even more importantly, the improvement provided by the MMB principle is not dependent on frequency or signal level. Linearity at very low levels — a weak point of conventional multi-bit converters — has been perfectly corrected.
HPC (High Performance Connection) Digital
receive the high-quality digital signals from the CD Transport DP-90, the DC-91 has dedicated HPC optical and balanced inputs. The optical input uses the same ultra-fast Hewlett-Packard link with a data transfer rate of 150 MBPS. The total absence of pulse distortion and jitter ensures absolutely pure digital signal transmission.
The HPC balanced link is totally impervious to externally induced noise and is therefore particularly suitable for installations where long cable runs are required. The output conforms to AES/EBU specifications, making it perfec for professional applications such as in broad casting or recording studios.
Thirteen Digital Inputs, Two Outputs and Three Sets of Terminals for Digital Recorders
Besides the HPC optical and balanced inputs, he DC-91 provides three optical and three poaxial inputs conforming to the EIAJ Digital Audio Interface standard. In addition, three sets of terminals for digital recording devices such as DAT, DCC, or MD devices are also prorided. One of these is a balanced connection, which conforms to the AES/EBU professional ormat.
All digital inputs are designed internally to handle 24-bit audio data, to allow for future expansion. Two 24-bit digital outputs are also provided, making the unit ready for the next generation of digital audio components.
HPC optical and Toslink optical transmitte
utomatic Selection of Three Sampling Fre uencies and Automatic Detection of Fre uency Precision in Three Stages
The number of digital program sources is increasing constantly, now encompassing DAT, DCC, MD, digital broadcast satellites, video discs with digital soundtrack, etc. The DC-91 can automatically detect and handle all three sampling frequencies currently in use. In addition, the EIAJ defines three levels of precision for sampling frequency accuracy: level 1 (±50 ppm), level II (±1000 ppm), and level III (±12,5%). If the frequency lock range of a processor is wider than a high-precision source requires, sideband noise will degrade sound quality. The DC-91 uses three quartz oscillators for level II, three lithium tantalate oscillators for level II, and a CR oscillator for level III, resulting in a total of seven PLL oscillators optimized for their respective precision level. A microprocessor automatically selects the proper oscillator
Absolute Phase Selection and Level Control in the Digital Domain
In a high-quality playback system, absolute phase can be critical. To prevent any possibility of sound quality degradation, the DC-91 allows absolute phase selection in the digital domain, thanks to the DSP (Digital Signal Processor) that has the capability to operate with 34-bit arithmetic precision. The signal level is also adjusted by the DSP chip with 24-bit output precision, which is 8 bits more than the 16-bit CD signal requires. This means that the level can be reduced by 8 bit (corresponding to -48 dB) before any degradation would occur. To further provide a safety margin, the control range is set to -40 dB
Input Selector with Mem
A unit with as many digital inputs and function as the DC-91 could be a nightmare when comes to remembering various signal levels frequency precision levels, and phase settings But the DC-91 is not only versatile, it is als easy to use, thanks to a built-in memory the stores all settings associated with every input
MMB principle, the DC-91 has a total of 32 l converters. Each converter in turn has a lo regulator with a positive and negative related power supply resulting in a total of
power supply circuits in this section alone. This avish design extracts optimum performance rom each converter
Block Diagram of DC-91
FRONT PANEL DP-90
- PLAY TRACK Indicator TRACK/INDEX Indicator
- Disc Tray OPEN/CLOSE Kev
- 6 PLAY (Playback Start) Key
- 6 POWER Switch 7 Disc Tray
- STOP Key TRACK SEARCH Keys
DC-91
REC-1, REC-2, REC-3 (Recorder) Selector Keys PHASE (Output Phase) Selecto
B LEVEL/–dB Indicators
put Position Indicators
EMPH PHASE, and Sampling
- SFA (Sampling Frequency
- OUTPUT LEVEL Adjust Keys
DP-90 HPC optical fiber output
- Toslink optical fiber output
- HPC digital output balanced
-
O Coaxial output jack Unswitched AC outlet*
DC-91
- 8 HPC digital input balanced type
- Coaxial input jacks (Toslink/Coaxial)
- 6 REC1 output connector for
- REC2 input connector
- REC3 balanced-type input
- REC3 balanced-type output
- 24-bit digital output connector
- 1 Unbalanced type output jack for audio output
- Balanced type output connector 1) Ground, 2 Inverted (-),
- AC power cord
*Remarks:
The unswitched AC outlet may not safety standards or regulations applicable in the particular country to where the unit is destined
GUARANTY SPECIFICATIONS
(Guaranty specifications are measured according to EIAJ standard CP-307.)
Performance Guaranty
All Accuphase product specifications are guaranteed as
CD TRANSPORT DP-90
-
Product Type Digital Compact Disc playback unit
Format Standard CD format
-
Error correction principle: CIRC 500 - 200 rpm (constant
- linear velocity) 1.2 – 1.4 m/s, constant
-
Error correction principle: CIRC 500 - 200 rpm (constant
Data read Principle
- Non-contact optical pickup (semiconductor laser) Laser Type
- Digital Signal Output Format and Level (EIA) Timina precision: Level I
- Output –19 to –14 dBm HPC balanced Output –21 to –15 dBm (EIAJ)
- Wavelength 660 nm 0.5 Vp-p, 75 ohms eents 100/117/220/240 V. 50/60 Hz Power Requirements
-
Maximum Dimensions
- 475 mm (18-3/4") width x 149 mm (5-7/8") height x 379 mm (14-15/16") depth
- Weight 20.5 kg (45.2 lbs.) net
- 25.5 kg (56.2 lbs.) in shipping carton
DIGITAL PROCESSOR DC-91
- Product Type Input/Output Format Standard EIA format Quantization: 16 – 24 bit linear Sampling frequencies (automatic detection):
- Timing precision (automatic detection): Level I, II, III
-
- 20-bit 8-times oversampling filter Digital deemphasis, Tolerance: ±0.001 dB
- Channel Separation
- Rated Output Level and Impedance
- BALANCED: 2.5 V/50 ohms, XLR-type connector UNBALANCED: 2.5 V/50 ohms, RCA-type phono jack Output Level Control
- 0 to -40 dB in 1-dB steps (digital control)
Input -30 to -10 dBm minimum input 0.2 V, 250 ohms Input -27 to -15 dBm
- p, 75 orins 100/117/220/240 V, 50/60 Hz Power Requirements Power Requirements Power Consumption 42 W
- Dimensions
475 mm (18-3/4") width x 149 mm (5-7/8") height x 379 mm (14-15/16") depth
- Weight 22.5 kg (49.7 lbs.) net
- 27.5 kg (60.6 lbs.) in shipping carton
• Digital Signal Input Format (EIA)
Remote Commander RC-9
- (Supplied with DP-90, but also available as an option.) Remote control principle: infrared pulse
- Power supply:3V DC (IEC R03 (size AAA) batteries x 2) Dimensions: 66 mm (2-5/8") x 225 mm (8-7/8") x
-
Weight: 280 g (0.6 lbs.) (including batteries)
OPTIONAL PARTS
- •HPC Optical Fiber Cable HLG-10 (1m)'
- HPC Optical Fiber Cable HLG-10 (111) HPC Balanced-type Cable HLC-10 (1m) Toslink Optical Fiber Cable LG-10 (1m)
- (Each cable is available with a length of 2m, 3m, and 5m.)
- Digital processor unit
- Frequency Response 4.0 20,000 Hz ±0.3 dB
MMB type, 20-bit D/A Converter
- Digital Filter
- Total Harmonic Distortion
- Signal-to-Noise Ratio 120 dB
- Dynamic Range
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