Technics SU-G700M2: Reference class amplifier

The integrated amplifier Technics SU-G700M2 is part of the Grand series of components of this brand and is a reference class model. The device is made in a metal case on an anti-resonance chassis, and its front panel is decorated with chic dial indicators of the signal level. The amplifier operates in D-class, but uses Load Adaptive Phase Calibration (LAPC) technology depending on the load. It is known that the impedance of speakers connected to an amplifier varies with frequency, so a good amplifier should not have problems with changes in load impedance. Conventional switching amplifiers may have difficulty pairing with capricious speakers in terms of impedance.

Despite the fact that the amplitude characteristics of such amplifiers are improved using negative feedback, their phase parameters remain unchanged. Therefore, Technics engineers developed an adaptive optimization algorithm based on speaker impedance, which performs correction according to the ideal impulse response through digital signal processing, based on measuring the amplitude-phase frequency response of the amplifier with connected speakers. This method allows you to level out the frequency response, providing rich spatial sound. In fact, thanks to LAPC technology, the Technics SU-G700M2 not only amplifies the current signal, but also optimizes its own phase parameters depending on the load resistance, which changes with frequency. All this allows you to control any speakers.

The amplifier features patented JENO Engine technology designed to reduce jitter. Another proprietary technology, LAPC, is designed to automatically calibrate the phase and amplify the signal so that the acoustics receive the optimal power value, regardless of its characteristics. Thanks to the serious measures taken, the sound of the Technics SU-G700M2 is as rich and saturated as that of amplifiers built using traditional analog circuitry, but at the same time, the Technics SU-G700M2 is significantly superior to them in its ability to fully drive any acoustics.

The amplifier is built entirely using pulse-digital technology, which ensures exceptional signal transmission accuracy. Inside the case, the entire structure is divided into three isolated sections to eliminate crosstalk. The model received an improved high-speed power supply with low noise and the same gallium nitride (GaN) field-effect transistors and silicon carbide diodes as the SU-R1000. The pulse switching frequency was slightly increased from the usual 100 kHz to 400 kHz, which made it possible to stabilize the supply of voltage and current, as well as reduce the effect of modulation noise on sound quality. The amplifier power at 8 Ohms reaches 70 W per channel, and at 4 Ohms – 140 W. The Technics SU-G700M2 circuits are divided into three sections using partitions, which helps eliminate interference between circuit blocks. In addition to analogue, Technics SU-G700 has two coaxial and two optical inputs, as well as two USB inputs for connecting a PC. The signal at the latter is filtered to eliminate external interference.

To further reduce internal noise, some amplifier circuitry can be disabled at user discretion. To support analog connections, the Technics SU-G700M2 is equipped with Burr-Brown PCM1804 ADCs. They provide analog signal processing at 24-bit/192 kHz, thus maintaining detailed and balanced sound. The Technics SU-G700M2 model also provides an input for a vinyl player, and the corresponding phono stage circuit is implemented using field-effect transistors and has a switchable gain. The device also has a separate headphone amplifier, built using a completely analog circuit and operating in class AA.