Premium High-grade D/A Converter and Dual Mono Construction D/A Circuit
For analogue audio output, the D/A circuit is one of the most important circuit blocks since it recreates the original analogue waveform from a digital source, such as a CD. For the D/A converters, Asahi Kasei Microdevices’ top-of-the-line DAC AK4497, with their high S/N ratio and low distortion, are isolated for the left and right channels. The power supply for the D/A converters is separated into five sections according to the application, and supplied individually. The power supply for the clock employs an original Battery Driven Circuit System to achieve high-accuracy D/A conversion. The Dual Mono Construction and symmetrical layout eliminate mutual interference between left and right channels, taking the reproduction of sound imaging and sound space recorded in the source to a higher dimension.
Discrete AMP Module
For analogue audio output, the filter circuit located after the D/A conversion determines the quality of the sound. The SL-G700’s filter circuit incorporates not an operation amp IC but an amp module of original discrete construction. The use of low-noise transistors and thin-film resistors suppresses the noise generated inside the circuits. Detailed fine tuning, such as the increase of operating current, has improved the response, S/N ratio and distortion rate. As result, the SL-G700 provides highly linear and faithful sound reproduction without omitting even the smallest nuances recorded in the source.
High-speed Silent Hybrid Power Supply
The quality of the power supply is extremely important for high-fidelity sound reproduction. Power supply noise and supply stability directly affect the quality of sound reproduced from audio signals, particularly for analogue audio output. The SL-G700 is equipped with a dedicated power supply unit for analogue audio output. Its non-feedback switching power supply suppresses switching frequency fluctuation. Combined with the original stabilized power supply circuit, this dedicated power supply unit provides stable power with low noise. The discrete circuit structure does not use any general-purpose ICs but a discrete layout and meticulous tuning provides power optimized for analogue circuits, thus realizing a high S/N ratio and superb reproduction, the hallmark of Technics sound.
Battery Driven Clock Generator
In the processing of digital audio signals, the quality of the clock affects the sound quality to a large extent. The best power supply for delicate circuitry such as the clock block in the DAC and the audio system clock circuit is one entirely isolated from any noise or fluctuations in the mains supply. Technics has extensive experience in isolating the power supply using a battery. This technology creates ultra-low-noise digital audio interfaces including D/A convertors. Additionally, the audio system clock is supplied from an Ultra-Low Jitter Clock Generator. A low-noise power supply and a high-quality clock circuit realize a sound with highest transparency.
Digital Noise Isolation Architecture
For the USB input terminals, the amplifier includes power conditioners using non-magnetic carbon film resistors with strong protection against magnetic distortion and using capacitors of high-quality ruby mica, excellent in characteristics such as low dielectric loss, high voltage resistance and temperature stability. In addition, high reproducibility of sound is pursued by various noise countermeasures, such as the installation of a low ESR film capacitor to the LAN terminal power supply and isolation by a pulse transformer in the digital output signal.
Optimally Activated Circuit System
The Optimally Activated Circuit System allows the operation of various digital modules to be stopped – such as those used for display, analogue and digital interfaces – to minimize the noise generated when music is playing.
High-quality Headphone Output
Generally, the analogue output signal (Balanced/Unbalanced) and headphone output signal are generated by the same D/A circuit. The SL-G700 is equipped with a dedicated D/A circuit for headphones which is independent from that for analogue output. This circuitry incorporates Technics’ original sound processing LSI, the JENO Engine (Jitter Elimination and Noise-shaping Optimization). Complete separation of the analogue output from the headphone output has eliminated the mutual interference between the two circuits that serve different purposes. In addition, each circuit has received the most suitable sound tuning. As a result, both outputs provide maximum performance.
Furthermore, the SL-G700 is equipped with an operation optimization system that automatically turns on the JENO Engine when a pair of headphones is connected. This eliminates the adverse effect of the analogue output on the sound quality when headphones are not connected. What’s more, the Class AA system headphone amp uses separate amp circuits for the audio signal voltage amplification and current amplification. The high-grade operation amp amplifies voltage, and the separate operation amp with high power supply capacity amplifies current. This enables high-precision conversion of the high-resolution PWM signal output from the JENO Engine to an analogue signal. Achieving ideal drive of headphones with a wide range of load impedance, it delivers low-distortion sound across a broad frequency range.