Audio Database

The stereo Integrated Amplifier which pursued the reproduction sound of good quality.

The head amplifier is built in so that the MC cartridge can be directly connected.
Four MOS FETs are configured with parallel push-pull to achieve 130W/ch.

All the amplification stages from the entrance of a head amplifier to the final of MOS FET are constituted by the perfect symmetrical push pull circuit.
This circuit requires nearly double the number of components compared to the normal system, but it has the advantage that low distortion can be realized with a small amount of NFB because it is excellent in elementary characteristics, especially linearity.
Thereby, TIM (transient intermodulation) distortion which deteriorates sound quality is improved significantly.

All unit amplifiers have a DC configuration.
Moreover, the DC cut capacitor of the NF loop which requires a large capacity is removed and the coloration is removed.
By adopting the newly developed DC servo system, we succeeded in suppressing DC drift, realized the difficult DC conversion of the tone control circuit, and are now operating as a DC amplifier even when using tone control.

In order to further reduce the coloration by the capacitor, the ICL system which removed the input capacitor of each unit amplifier is adopted.
Therefore, there is only one capacitor between the outputs from AUX and Tuner.

The input is composed of an ultra-low noise transistor with a differential push-pull, realizing a low input conversion noise level of -150dBV in combination with the low impedance of the NF loop. Also, a wide dynamic range that does not cause clipping with any MC cartridge is secured.
Also, because it does not have a capacitor, there is no coloring due to the capacitor.
The head amplifier can be easily switched with one switch for both DISC1 and 2 inputs so that it can be easily adapted when using two arms.

The equalizer amplifier makes the current of a final transistor large, makes it class A operation, and lowers output impedance, and the NF loop is also made into low impedance by this, and the noise generated in a differential input circuit is reduced sharply.

The high efficiency, low leakage flux type which adopted CI core is adopted as a power transformer.
This CI type core is the same as the one used for the columnar transformer of the household power supply where the load fluctuation is severe, and because the winding is a two-division balanced type, there is little leakage flux, and the efficiency is good and the fluctuation rate is also excellent. I am.

The expansion of the tone control function is measured and the turnover changeover switch is carried.
As a result, Bass can select 200Hz and 500Hz, and Treble can select 2kHz and 7kHz.
The change method is performed with an 11-contact rotary switch, and the change in step can be kept accurate.
It also has a tone control ON/OFF switch.

The loudness compensator switch which corrects the hearing at the time of a low volume play, and adjusts energy balance is carried.
You can select three types of curves according to the playback level and the characteristics of the listening room.

The subsonic filter of 17Hz and 12dB/oct is carried.
The sound quality at the time of ON is emphasized, the input active element of the high level amplifier is utilized, the active filter is formed only by adding CR without adding an active element, and the sound quality deterioration is suppressed.

The output meter is carried and the output can be read directly by the logarithmic compression type peak instruction.

A-20 dB attenuator switch, which is convenient when searching for the start point of a record, a DISC input impedance selector switch, a switch that cuts off the recording output circuit when not using a tape recorder, and a switch that prevents distortion from occurring, a preamplifier and a power amplifier are independent It is equipped with useful functions such as a separate switch to be used.

There is a wood case sold separately.

Type Stereo integrated amplifier
Rated output (High Level Input,
When both channels are operating, 20Hz-20kHz,
(Distortion rate 0.02% or less)
4Ω load: 180W/ch
8Ω load: 130W/ch
16Ω load: 65W/ch
Harmonic distortion (between 20Hz and 20kHz) High Level input → output: 0.02% or less (at rated output)
High Level input → Pre out: 0.005% or less (at rated output)
DISC (Head Amp:off) → Tape Rec out: 0.005% or less (at 6V output)
DISC (Head Amp:on) → Tape Rec out: 0.01% or less (2V output)
IM distortion rate 0.01% or less (High Level Input, at rated output)
Frequency characteristics High Level Input:20Hz~20000Hz +0 -0.2dB
DISC Input: 20Hz ~ 20000Hz +0.2 -0.2dB
Damping factor 80 (8Ω load, 40Hz)
Rated input/input impedance DISC1(Head Amp:OFF):2.5mV/100, 47k, 82k, 150kΩ
DISC1(Head Amp:ON):0.125mV/100Ω
DISC2(Head Amp:OFF):2.5mV/47kΩ
DISC2(Head Amp:ON):0.125mV/100Ω
High Level Input: 160mV/47kΩ
Main Input: 1.3V/47kΩ
DISC maximum input (distortion rate 0.005%, 1000Hz) Head Amp OFF:300mVrms
Head Amp ON:15mVrms
Rated output/output impedance Pre Output:1.3V/200Ω
Tape Rec Output: 160mV/200Ω (for DISC)
Headphones: 0.32V/Compatible impedance 4-32Ω
Gain Main Input → Output:27.8dB
High Level Input → Pre Output: 18.4dB
DISC Input(Head Amp:OFF) → Tape Rec Output:36dB
DISC Input(Head Amp:ON) → Tape Rec Output:62dB
S/N / Input conversion noise (input short,
(IHF-A curve, at rated input)
Main Input:115dB/-112dBV
High Level Input: 100dB/-116dBV
DISC Input(Head Amp:OFF):86dB/-138dBV
DISC Input(Head Amp:ON):72dB/-150dBV
Volume adjustment interlocking error within 1dB
Tone control
bass 500Hz:±10dB(100Hz)
200Hz: ±10dB(50Hz)
2dB step
2dB step
treble 2kHz:±10dB(10kHz)
7kHz: ±10dB(50kHz)
2dB step
2dB step
Loudness compensator COMP1:+6dB(50Hz)
COMP2: +9dB (50Hz)
COMP3: +10dB (50Hz), +4dB (15kHz)
(Volume control, at -30dB)
Subsonic filter 17Hz, -12dB/oct
Attenuator -20dB
Power meter Logarithmic compression type peak level instruction
Direct reading of output at dB and 8Ω load
Load impedance 4-16Ω
Semiconductor used 113Tr, 18FET, 2IC, 39Di
power supply 100V, 117V, 220V, 240V/50Hz, 60Hz
Power consumption No input: 100W
8Ω load rated output: 490W
Outer dimensions Width 445 x height 160 (including legs) x depth 370 mm
weight 20kg
Sold separately Wood Cabinet A-8 (¥15,000)