Technics SU-GX 70 Streaming-Amplifier

TECHNICS SU-GX70

The SU-GX70 uses fully digital, proprietary Technics amplifier technology. This transmission system processes the signals completely digitally across all stages - from the input to the output stages. Compared to analog amplification systems, this principle is less prone to signal degradation from noise, thus ensuring higher precision in signal transmission. Not only digital, high-resolution input signals benefit from the accurate signal processing, but also analog music sources with their fine nuances.

Furthermore, a JENO engine is also used in the HDMI ARC (Audio Return Channel) circuit, which is used for the first time in a Technics product. This helps to avoid sound degradation caused by jitter. The sound quality via HDMI benefits significantly from this.

Only high-quality components are used in the SU-GX70. Chip film capacitors, for example, are used to contain the power supply noise and for signal coupling.

Overview

• Derived from reference-class components, the JENO Engine (Jitter Elimination and Noise-shaping Optimization) transmits and processes audio signals with minimal jitter from the input to the output stage
• The load-adaptive phase calibration (LAPC) enables ideal frequency response and phase characteristics on every speaker
• Double power supply design including high-speed silent power supply for extremely low noise
• Optimized video outputto eliminate negative effects on the ARC lines
  • High-frequency ON/OFF switching of the video signal in the HDMI chip can cause noise and thus affect the audio signal. Therefore, with the SU-GX70, all Y/Cb/Cr video signal data is set to “00000000”(8-bit operation) to prevent noise interference and thus keep the audio signal over HDMI as pure as possible
• High-quality audio playback from the video source: Thanks to the know-how of the Technics engineers in the special video signal processing, you can also enjoy high-quality audio playback from video sources.
• Compatible with many music sources: The SU-GX70 supports a wide range of music sources such as radio (analogue FM + digital), analogue inputs, phono MM, digital optical (eg from TV), coaxial digital and USB.
• High-quality sound enjoyment, wireless:The SU-GX70 plays high-resolution music wirelessly from a smartphone, tablet or PC. Not only does it support Bluetooth ® and AirPlay2, but also Spotify Connect ® , Internet radio and Chromecast built-in™
• Device design is becoming increasingly important with modern hi-fi components. Good device design is therefore a must for Technics. The front panel of the SU-GX70 consists of 7mm thick brushed aluminum with an elegantly milled Technics logo. The rotary volume control is milled from solid aluminium. Tactile quality and operation are a delight.

Ideal impulse response by LAPC

A speaker's impedance changes with frequency. However, a power amplifier must drive speakers regardless of their specific characteristics. With conventional digital amplifiers, the loudspeakers are driven via a low-pass filter in the output stage. Therefore, they are all the more influenced by the impedance characteristics of the connected speakers. The amplitude characteristics of conventional amplifiers can be improved with negative feedback. However, the phase characteristics cannot be improved. Therefore, we developed an adaptive speaker impedance optimization algorithm. This corrects the impulse response of the loudspeaker using digital signal processing by measuring the amplitude-phase characteristics of the amplifier with loudspeakers connected. This new method enables the frequency response characteristics of amplitude and phase to be smoothed, which is not possible with conventional amplifiers. The timing of the resulting amplifier signal leads to a sound image with precise spatiality.

Space Tune™ for perfect sound adaptation to the room

The SU-GX70 has a so-called "Space Tune" function, with which the system can be adapted to the spatial conditions and the installation location of the loudspeakers. Thus, all listeners can benefit from optimal music reproduction. Either the measurement function of the Technics Audio Center app (for tablets or smartphones with iOS) is used, or you simply use the four presets "Freestanding," "Near the wall," "Near the corner" and "On the shelf", which relate to the installation location of your speakers. This allows you to adapt the playback quality specifically to your spatial conditions.

In addition, different placement conditions can be taken into account for the left and right loudspeakers. This allows the best possible reproduction to be achieved under all installation conditions.

Dual power supply

The power supply is an extremely critical component in audio equipment. Particular attention must be paid to the power pack, especially in amplifiers where small signal groups, but also output stages that deliver large currents are installed. In order to rule out any disruptive effects on the amplifier section, the SU-GX70 has its own power supply for the output stage circuit, which is decoupled from all other circuits.

The same electrolytic capacitors are used in this as in the larger Technics amplifiers.

The SU-GX70 also ensures low noise and low internal resistance thanks to the shortest possible connection between the power supply unit and the power amplifier. In addition, non-magnetic screws are used in the connection between the speaker terminals and the power amplifier.

Ultra fast and low noise

The SU-GX70 has a very fast switching power supply with an operating frequency of approx. 130 kHz. Increasing the switching frequency reduces noise from the power supply to the band of the music signal. This serves to ensure good sound reproduction and at the same time the powerful drive of the loudspeakers.

Top audio performance through extensive video know-how

In order for the SU-GX70 to receive audio signals through the HDMI ARC (Audio Return Channel), it must - according to the specifications - first output video signals. However, the output of these signals can introduce unwanted noise.

Therefore, in the SU-GX70, the video signals are output at a lower rate and the digital values for the color components of each pixel are set to zero. This enables a low-load data exchange between the HDMI transmitter and receiver assemblies. This avoids unwanted noise from the video signal. This also reduces harmful influences on the sound quality. The transmission of the signal from the TV set to the JENO engine via the shortest possible signal path also avoids the harmful effects of jitter. This mechanism is unique and demonstrates our expertise at Panasonic/Technics as an HDMI licensee.

Pure amplifier mode

In Amplifier Only mode, disconnecting the power supply from the network and HDMI circuits will eliminate any noise from those assemblies or from the antenna. Music playback, for example, benefits from analog signals or those via SPDIF.

Analog inputs with discrete amplifier trains

The discrete amplifier trains in the SU-GX70 have been taken from the SU-R1000 and modified, using the same balanced layout.

In addition, similar high-quality audio components have been adopted elsewhere from the SU-R1000, such as low-noise FETs, thin-film resistors, film capacitors, and electrolytic capacitors. The SU-GX70 was fine-tuned down to the smallest detail.

Technical specifications

• amplifier
  Amplifier principle: fully digital (JENO)
  Output power at 8?: 40W/ch(1kHz, THD1.0%, 20kHz LPF)
  Output power at 4?: 80W/ch(1kHz, THD1.0%, 20kHz LPF)
• Analog inputs: 2 x Line In (RCA), Phono (MM)
• Digital inputs: 2 x optical (TOSLink), 1 x coaxial, 1 x USB-A, 1 x USB-B, 1 x HDMI ARC
• analog outputs
  1 x preamp output/subwoofer output (with built-in low-pass filter)
  1 x 6.3mm headphone output stereo jack
• streaming services and other functions
  Chromecast
  Spotify
  Tidal
  deezer
  Qobuz
  Amazon Music
  air play 2
  MQA
  Roon-ready (network-based update at a later date
  FM (VHF) radio
  DAB+
• weight and dimensions
  Weight 6.6kg
  Dimensions (HxWxD) 430 X 98 X 368 mm