Technics SH-X1000

Commentary

Digital processor with 3-chip configuration Mash 1-bit DAC.

The D/A converter is equipped with multi-stage noise shaping (Mash) using high-order oversampling technology and noise-shaping technology.
In this method, a digital filter oversamples the 16-bit digital signal and pushes the folded signal to the high-frequency band. Then, a multi-stage noise-shaping circuit called Mash compresses the 16-bit signal, and a pulse width modulation (PWM) circuit replaces it with a corresponding pulse. At this point, only low and high bits become one bit, and D/A conversion is performed with no relative accuracy errors in the amplitude direction. This realizes D/A conversion with no theoretical 0 cross distortion or non-linear distortion, and can reproduce low-level signals small signals superimposed on large signals without distortion.
The SH-X1000 has a 3-LSI configuration with 1 LSI of digital filter, Mash and 1-bit DAC and 2 LSI of left and right independent DACs including PWM converter. Channel separation is improved by preventing digital noise from entering the PWM chip.
The operating clock of the digital filter + Mash and PWM chip is 64 fs, and the theoretical dynamic range of 123 db is realized.

A jitter-free interface is installed to eliminate jitter that occurs in digital transmission systems.
In this circuit, data is first stored in 1.5 megabit RAM via DSP, then read out from RAM by high-precision quartz clock independent independent from the clock on the sending side, and transferred to the digital filter + Mash chip at the later stage. In principle, jitters are stored in the RAM and become 0 when read out.
Since this circuit has a slight time lag when the RAM usage is large, two types of RAM usage, Narrow and Wide, can be selected depending on the frequency deviation of the source.
This interface conforms to the EIAJ standard and provides excellent signal transmission when connected to other digital devices such as DAT and BS tuners.

A DSP is installed to suppress group delay distortion generated around the phase of the low-pass filter. The entire linear phase is realized by phase correction with inverse characteristics to the low-pass filter of the latter stage.

It adopts digital emphasis processing by DSP instead of emphasis circuit done by analog circuit.
DSP processing simplifies the circuit and improves the S/N ratio, etc.

It is designed to operate in high-precision digital PLL mode when the frequency deviation of the input source is large.
The phase difference between the digital signal input to the DSP and the clock from the VCO is detected using the RAM. The VCO is controlled by the phase difference output of approximately 10 sec. This drives the jitter out of the audible band and enables the generation of a clock with high oscillation accuracy.

The power supply section uses a large transformer with vibration isolation structure for both digital and analog power supplies. It also uses an active shunt power supply to reduce power supply voltage fluctuations caused by circuit operation.

We have succeeded in suppressing pressure fluctuation to the limit.

A classAA unique to Technics is used for the lineout circuit.

It uses carefully selected parts such as glass epoxy boards and audio PXS capacitors.

Model Rating

Type	D/A converter
<Audio section>
Number of channels	2 channels (stereo)
Output voltage	Unbalanced : 2.5 Vrms (EIAJ) Balance : 2.5 Vrms
Frequency characteristic	2 Hz to 20 kHz ± 0.2 dB
Dynamic range	98 dB or More (EIAJ)
Signal-to-noise ratio	120 dB or more (EIAJ)
Total harmonic distortion factor	0.0008% or less (EIAJ)
Channel separation	110 dB or more (EIAJ)
Digital filter	24-bit high-resolution output 8 x oversampling
D/A converter	64 fs Twin PWM 8 dac System
Output impedance	Unbalanced : 600 Ω Balance : 600 Ω
<input / output>
Digital input	EIAJ-compliant digital audio interface format Hikari Route 3
Sampling frequency (Digital Input)	32.0 kHz ± 0.1% 44.1 kHz ± 0.1% 48 kHz ± 0.1%
Digital output	EIAJ-compliant digital audio interface format One optical system
Audio Out	Unbalanced output 1 system Balanced output 1 system
<General>
Pwer	100 VAC, 50Hz/60Hz
Power consumption	20W
External dimensions	Width 484x Height 139x Depth 419 mm
Weight	20kg