SANSUI AU-D607X Decade
¥ 79,800 (released in 1985)
Commentary
Decade series integrated amplifier with twin diamond X balanced amplifier
The basic configuration of the amplifier is a twin diamond X balanced amplifier.
In the conventional amplifier, the current to the speaker is sent from the positive side and the negative side is simply connected to the ground. Therefore, when the back electromotive force flows into the ground on the negative side, IHM distortion occurs due to mutual interference with the ripple current of the current. In addition, NFB for reducing the distortion is only on the positive side, and the negative side is not controlled at all.
The Twin Diamond X balanced amplifier has a balanced configuration for all signal circuits from input to output, power supply circuits, and NFB circuits. By driving the speakers equally from both + and - sides, the influence of ground is eliminated.
In addition, in order to make the power transistor work more effectively, the speaker drive capability has been improved by adopting a two stage configuration in which the power transistor is driven by current using a twin diamond differential circuit.
The power supply section is a 3-power supply system, with a dedicated power supply for the predrive / equalizer and two independent power supplies on the left and right sides for high-power reproduction. The balanced power supply is completely isolated from the ground to reduce fluctuations caused by external influences and external influences.
The REC selector has an OFF position.
When a connected tape deck is OFF, the signal current flows into the front stage of the device and then returns to the amplifier from the front stage to prevent distortion.
Features such as subsonic filter, tone control, loudness and muting are included.
Uses AC power cord with polarity display.
The equalizer section uses a high-gain Hi-Precision equalizer with a discrete configuration.
This circuit is compatible with MC, High-MC and MM cartridges by gain switching.
Model Rating
| Type | Integrated DC amplifier |
| Power Amplifier Unit | |
| Effective output (10 Hz to 20 kHz, both channels driven) | 105W + 105W (6 Ω) 90W + 90W (8 Ω) |
| Total harmonic distortion rate (10 Hz to 20 kHz) | 0.003% (8 Ω, Effective Output) 0.005% (6 Ω, at 1/2 effective output) |
| Intermodulation distortion factor (60 hz : 7 khz = 4 : 1) | 0.003% (8 Ω, Effective Output) |
| Output Bandwidth (IHF, both channel operation, THD0.03%) | 5 Hz to 70 kHz |
| Damping factor (new IHF, 20 Hz to 20 kHz) | 80 (6 Ω) |
| Frequency Response (1W) | DC ~ 300 khz + 0 -3dB |
| Slew rate | ± 180 v / μ sec (6 Ω) |
| Rise time | 0.6 μ sec |
| Equalizer Amplifier Section | |
| Input Sensitivity / Input Impedance (1 kHz) | Phono MM : 2.5mV/47k Ω Phono High MC : 2.5mV/100 Ω Phono MC : 300 μ V/100 Ω CD, Tuner, Tape1, 2/PCM : 150mV/47k Ω |
| Phono maximum allowable input (1 kHz, THD 0.01%) | MM:300mV High MC:300mV MC High:30mV |
| Signal-to-noise ratio (A network, short circuit) | Phono MM:88dB Phono MC:70dB CD, Tuner, Tape : 110 dB |
| Tone control | Bass : ± 10 dB (50 Hz) Treble : ± 10 dB (10 kHz) |
| Subsonic filter | 16 Hz (-3dB, 6dB/oct.) |
| Muting | -20dB |
| <General> | |
| Rated power consumption (Electrical Appliance and Material Control Law) | 230W |
| External dimensions | Width 466x Height 161x Depth 431 mm |
| Weight | 15.0kg |
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