SANSUI AU-D607

Commentary

This is a DC pre-main amplifier equipped with a diamond differential circuit that identifies the essence of audio amplifier as music playback.

The design further improves the DC conversion of the amplifier section. The equalizer section, flat amplifier section, and power amplifier section are all composed of DC amplifiers with excellent dynamic characteristics.
In addition, all block stage inputs are all FET inputs and are used as a push-pull input circuit, and the input capacitors of all block stages are eliminated in the direct coupling system.
This eliminates the low-frequency phase rotation that occurs when a capacitor enters the signal path, and other factors that degrade sound quality. As a result, pure music signal transmission and a wide range are achieved.

A diamond differential circuit is mounted on the power amplifier.
The first stage adopts a differential circuit with constant current using dual FET capable of passing a large current with low noise characteristics, and the second stage adopts a diamond differential circuit with cascode bootstrap.
And, NM (Non Magnetic) transistor with good linearity is used for the power stage, and the whole circuit is composed of symmetrical symmetrical circuit and 2 pole phase correction circuit, which realizes waveform transmission with little distortion up to high frequency range.

The circuit configuration of the equalizer amplifier section is a direct-coupled system in which input capacitors that cause sound quality degradation are removed. A high-stability, low-noise, high-gm dual FET is used for the first stage, a push-pull drive with two differential stages and a current differential with a current mirror is used, and a pure SEPP output is provided.
The equalizer for the NF circuit uses a high-precision metal film resistor and a styrofoam capacitor with low capacitance error and excellent temperature characteristics.

The flat amplifier section also uses a direct coupling method without input capacitors that are not effective in sound quality.
The first stage consists of cascode connection and differential amplification with current source using dual FET of low-noise and high-gm, and the second stage consists of 8 devices using current differential push-pull circuit with current mirror. Like the DC power amplifier section, it has excellent open-loop characteristics to reduce TIM distortion.
When the tone is turned on, the flat amplifier is switched to an NF-type tone amplifier, which provides a simple tone control characteristic with less distortion.

The power supply section is a 2-power transformer, and the left and right sides are completely independent.
In addition, by using 12,000 μ Fx4 electrolytic capacitors and metalized film capacitors, low impedance characteristics from ultra-low band to ultra-high band are achieved.

Equipped with MC head amplifier.

Equipped with a loudness switch, subsonic filter, Tone defeat switch and balance control.

Tape play function and tape copy function can be performed independently, and the tuner signal can be extracted independently for recording.
For example, you can air check while listening to a record.

The speaker output can be connected in two ways : OFF, A, B, or A + B.

Three spare AC outlets (100W for one interlocked circuit, 250W for two non-interlocked circuits) and ground terminal are mounted.

Pre-power and power can be separated.

Model Rating

Type	Wide-range DC pre-main amplifier
Power Amplifier Unit
Effective power	70W + 70W (10 Hz ~ 20 kHz, THD 0.008%, 8 Ω) 70W + 70W (1 kHz, THD 0.003%, 8 Ω)
Total harmonic distortion factor	0.008% or Less (10 Hz to 20 kHz, 8 Ω at Effective Output)
Intermodulation distortion factor (70 hz : 7 khz = 4 : 1)	Not more than 0.008%
Output bandwidth	5 Hz ~ 70 kHz (IHF, Both Channel Operation, 1 kHz, 8 Ω)
Damping factor	100 (IHF, Double-channel Operation, 1 kHz, 8 Ω)
Frequency characteristic	DC ~ 400 kHz, + 0 -3dB
Input Sensitivity / Input Impedance	1V/47k Ω (1 kHz)
Signal-to-noise ratio	125 dB or more (IHF, A-network, short circuit)
Channel separation	90 dB or More (IHF, 1 kHz)
Rise time	0.5 μ sec
Slew rate	± 160 V / μ sec
Preamplifier Section
Input Sensitivity / Input Impedance (1kHz)	Phono-1MM : 2.5mV/47k Ω Phono-2MC Only : 0.1mV/100 Ω AUX, Tuner, Tape Play 1, 2 (PIN) : 150mV/47k Ω
MC compatible impedance	100 Ω or less
Phono maximum allowable input (1 kHz)	Phono MM:300mV(THD 0.01%) Phono MC:15mV(THD 0.03%)
Output Voltage (1 kHz)	Tape Rec1, 2 (at PIN, 47k Ω) : 150 mv Pre Out (at 47k Ω) : 1 V Max Pre Out (at THD 0.05%, 47k Ω) : 4 v
Output Impedance (1 kHz)	Tape Rec1, 2 : 600 Ω or less
Total harmonic distortion factor	Phono MC (1 kHz, 6 V) : 0.01% or less Phono MM (20 Hz to 20 kHz, 6 V) : 0.005% or less AUX, Tuner, Tape Play 1, 2 (20 Hz to 20 kHz, 1 V) : 0.005% or less
Intermodulation distortion factor (70 hz : 7 khz = 4 : 1)	AUX, Tuner, Tape Play 1, 2 (1 v) : not more than 0.005%
Frequency characteristic	RIAA deviation (Phono 1, 2, 20 Hz-20 kHz) + / - 0.2 dB AUX, Tuner, Tape Play 1, 2 : 5 hz to 100 khz, + 0 -1dB
Signal-to-noise ratio (IHF, A-network Short circuit)	Phono MC (input conversion) : -152dBV Phono MM : 88 dB or more AUX, Tuner, Tape Play 1, 2 : 100 dB or more
Channel separation (IHF, 1 kHz)	Phono MC : 70 dB or more Phono MM : 70 dB or more AUX, Tuner, Tape Play 1, 2 : 75 dB or higher
Input-to-input separation (input short, 1 kHz)	Tuner ⇔ Phono MM : 90 dB or higher Tape Play 1, 2 ⇔ Phono MM : 90 dB or more Tuner ⇔ Tape Play 1, 2 : 90 dB or higher Tape Play 1 ⇔ Tape Play 2 : 90 dB or higher
Tone control	Bass : ± 10 dB (50 Hz) Treble : ± 10 dB (15 kHz)
Subsonic filter	16 Hz (-3dB, 6dB/oct.)
Loudness (at volume -30dB)	+10dB(50Hz) +4dB(10kHz)
Headphone jack output	85 mw (8 Ω)
<General>
Load impedance	4 ~ 16 Ω
Rated power consumption	195W (Electrical Appliance and Material Control Law)
External dimensions	Width 430x Height 168x Depth 390 mm With Rack-Mount Adapter : Width 482x Depth 418 mm
Weight	15.5kg With rack-mount adapter : 16 kg
Sold Separately	Rack-Mount Adapter BX-7 (1 pair, ¥ 3,000)