Technics SU-V90D

Commentary

Pre-main amplifier equipped with D/A converter.

The D/A conversion section uses a 4-DAC 18-bit conversion system.
In the 4DAC 18-bit conversion system, two D/A converters are installed in each L/R channel to process the + and - components of the input signal independently. A total of four D/A converters are used in the 4DAC conversion system. In this circuit, first of all, a newly developed 4 DAC processor LSI distinguishes between + and - signals from the input digital signal, and high-speed processing is performed by switching two D/A converters. This realizes D/A conversion without 0 cross distortion in principle.
In addition, the D/A converter achieves 18-bit operation at an average music level of -12dB or less by using a 4 DAC processor LSI. This, combined with the use of a 4 x oversampling 18-bit digital filter, provides more faithful analog waveform reproduction capability.

Three sampling frequencies, 32 kHz, 44.1 kHz and 48 kHz, are available for use with CD players, DAT and BS tuners.

The digital input has two systems, optical and coaxial.

The power amplifier section is equipped with a VC-4 amplifier (Voltage Current 4 amplifier system) classAA amplifier.
In this circuit, voltage control and current drive are handled by separate amplifiers for each L/R channel, so that the voltage control amplifier is released from current supply. Voltage control is achieved with high fidelity to the input signal, and the current drive amplifier has sufficient current supply capability for speaker drive.

The power supply section is equipped with a power transformer using high-density and high-efficiency technology based on the OFC wire perfectly aligned winding method.
We have also adopted a newly developed high-speed EX electrolytic capacitor for power supplies. This capacitor uses biotechnology to improve the purity of the electrolytic solution by more than two orders of magnitude and eliminates the slight distortion caused by impurities attached to the electrodes.

Equipped with a power amp direct function which is a further development of CD direct function.
With this function, the direct input signal of the power amplifier and the output signal of the built-in D/A converter are directly input to the power amplifier only via the classAA buffer and the input volume of the power amplifier, enabling high-purity amplification. Together with the use of the P. C. L. low-impedance volume for the input volume of the power amplifier, the S / N ratio is improved by approximately 10 dB.

We also conduct thorough performance analysis and trial listening in the selection of audio-only parts, and carefully select high-purity OCC and OFC materials for internal wiring and lead wires of each part.

In order to reduce the sound quality degradation caused by the vibration of the amplifier, vibration isolation measures such as a large metal insulator are provided.

To prevent interference between the digital circuit, phono equalizer circuit and power amplifier circuit, each block is carefully shielded. In addition, the active servo power supply is used to eliminate interference through the power supply, and sound quality degradation due to interference between sources is completely eliminated.

Model Rating

Type	Integrated amplifier
Effective output (20 Hz to 20 kHz)	120W + 120W (6 ohm, 0.005%)
Total harmonic distortion factor	0.002% (Rated Output -3dB, 20 hz to 20 khz)
Frequency characteristic	20 Hz ~ 20 kHz + 0 -0.2 dB 0.8 Hz ~ 150 kHz + 0 -3dB
Signal-to-noise ratio	115 dB at IHF' 66, Power Amp Direct
Damping factor	80 (8 Ω)
Load impedance	Main or remote : 6 Ω ~ 16 Ω
Input Sensitivity / Impedance	Phono MM : 2.5mV/47k Ω Phono MC : 170 μ V/220 Ω Tuner, CD, aux, tape : 150mV/22k Ω
Phono SN ratio	MM : 88 dB (2.5 mV input) MC : 72 dB (250 μ V Input)
Tone control	Bass : ± 10 dB (50 Hz) Treble : ± 10 dB (20 kHz)
Loudness control (VR-30dB)	+9dB(50Hz)
Pwer	100 VAC, 50Hz/60Hz
Power consumption	220W
External dimensions	Width 478x Height 158.4x Depth 397 mm
Weight	14.7kg