Audio Database
A-7
Commentary

A pre-main amplifier with a Reserve II power supply developed by inheriting the circuit technology of A-11.
It has a simple configuration with accessories that only have the features you need.

A parallel push-pull circuit is mounted on the final power stage.

Stage independent 4 power supply and reserve II power supply are used for the power supply.
This is a further development of the reserve power supply. The phase of the power supply output is delayed by 90 degrees to fill the valley of the ripple. This prevents the voltage drop that occurs when a capacitor input power supply attempts to obtain a large output when the capacitor is discharged.

A high-gain equalizer amplifier is installed to support MC cartridges.
It has a circuit configuration using a low-noise high-gain FET, and is compatible with MM cartridges by a gain switching switch that can be used in two positions.

Model Rating
Type High-quality integrated amplifier
Power Amplifier Unit
Circuit system All-stage direct DC servo circuit
Effective output (both channel drive
Sine wave continuous output, 20 Hz to 20 kHz)
100W + 100W (4 Ω)
50W + 50W (8 Ω)
Total harmonic distortion factor (at effective output) Not more than 0.006%
Cross modulation distortion factor (at effective output) Not more than 0.006%
Frequency characteristic 5 Hz to 300 kHz
Preamplifier Section
Circuit system High Gm FET direct input EQ circuit
Input Sensitivity / Impedance Phono MM : 2.5mV/47k Ω
Phono MC : 250 μ V/100 Ω
CD, Tuner, AUX, Tape1, 2 : 150mV/47k Ω
Output Level / Impedance Rec Output : 140mV/2.2k Ω
Signal-to-noise ratio Phono MM:90dB(-142dBV)
Phono MC : 73dB/250 μ V (-145dBV)
CD, Tuner, AUX, Tape1, 2 : 110 dB (-126dBV)
RIAA deviation 10 Hz to 100 kHz ± 0.2 dB or less
Phono maximum allowable input MM:150mV
Muting -20dB
Subsonic filter 15 Hz (-3dB, 6dB/oct, built-in phono equalizer)
Input-output phase Inphase
<General>
Power supply circuit system Shunt power supply system + reserve power supply
Power consumption 190W
External dimensions Width 430x Height 150x Depth 380 mm
Weight 13kg