Audio Database

Image of A-636
Commentary

A pre-main amplifier that inherits the design concept of A-838 and adopts a non-vibration and non-resonance design such as a clean ground system and direct construction II.

It uses a clean ground system to prevent harmful noise currents generated by power transformers and heat sinks.
Power transformer and heatsink isolated from chassis and installed Noise is prevented from entering the signal path, and a special bypass is provided to return the noise current to the noise source to prevent noise from entering the music signal.

It is equipped with Direct Construction II which realized the shortest signal path length of 85 cm by further developing the direct construction which achieved the signal path length of 120 cm.
The input block is designed to mechanically remotely control the input selector and main volume. In addition, the source direct switch is turned ON to prevent input signals from flowing to the front panel.
In addition, by laying out the volume substrate on the power amplifier, the routing of excess wiring is extremely shortened compared to conventional ones.
In addition, the power amplifier block is arranged along the signal path to direct the output of the power stage directly to the speaker selector block to minimize the distance from the power supply.
In the speaker selector block, the speaker terminals are directly attached to the circuit board on which the relay is attached, eliminating the waste of wiring.

In order to ensure no vibration and no resonance, the honeycomb shape with high rigidity and excellent vibration damping is adopted for main parts such as chassis and heat sink to keep vibration strain low. In addition, the heat radiation effect is improved by adopting the chimney type honeycomb heat sink.
The volume uses a balanced volume shaft that reduces mechanical stress.
It is also equipped with a large honeycomb insulator that disperses and attenuates external vibration in various directions.

Non-switching circuit type II is adopted to improve switching distortion, thermal distortion, and nonlinear distortion of the output stage.

The NF-CR type is used for the Phono equalizer.

Considering the influence of external noise, oxygen-free copper wire power cord with polarity display is adopted, and nickel phosphorus plating which reduces non-linear strain is used for the power plug.
We have also adopted a vice type speaker terminal to supply current with less loss.

It uses an audio fuse with an emphasis on sound quality and a rotary knob made of machined aluminum material.

It has S jacks for input Route 3 and output Route 3, and a built-in video selector that enables mutual dubbing between the S jacks.
In addition, in order to maintain the design philosophy of giving top priority to sound quality, we have separated the circuit and ground for audio and video systems and installed a dedicated transformer to prevent interference with audio systems.
In addition, with the V function OFF, it is possible to turn off the power of the video system with one touch operation. When the Direct switch is turned OFF in the OFF position, the audio source can be played back by VCR.

Model Rating
Type Stereo pre-main amplifier
Amplifier Unit
Rated Output (20 Hz to 20 kHz, Both Channel Drive) 120W + 120W (4 Ω, 0.008%)
100W + 100W (6 Ω, 0.005%)
90W + 90W (8 ohm, 0.005%)
Damping factor (1 kHz, 8 Ω) 200
Input Sensitivity / Impedance Phono MM : 2.5mV/50k Ω
Phono MC : 0.2mV/100 Ω
CD, Tuner, VDP, VCR, Tape : 150mV/50k Ω
Phono maximum allowable input (1 kHz, 0.008%) MM:200mV
MC:19mV
Output Level / Impedance Tape Rec, VCR Rec : 150mV/2.2k Ω
Frequency characteristic Phono MM : 20 Hz to 20 kHz ± 0.2 dB
Phono MC : 20 Hz to 20 kHz ± 0.3 dB
CD, Tuner, Tape : 1 hz to 150 khz + 0 to 3 db
S/N ratio (IHF, A-network
Short circuit)
Phono MM:89dB(2.5mV)
Phono MC:71dB(0.25mV)
CD, Tuner, VDP, VCR, DAT/Tape1, Tape2 : 110 dB
<Composite Video Part>
Input Sensitivity / Impedance VDP, VCR1, 2, TV/AUX : 1Vp-p/75 Ω
Output Level / Impedance Monitor, VCR1, 2 : 1Vp-p/75 Ω
DG Not more than 2%
DP 2 degrees or less
Frequency characteristic 10 Hz to 10 MHz + 0 -1dB
Signal-to-noise ratio 60 dB or more
S-Video Terminal Unit
Input Sensitivity / Impedance VDP, VCR1, 2
Luminance Signal : 1Vp-p/75 Ω
Color Signal : 0.286Vp-p/75 Ω
Output Level / Impedance VCR1, 2, Monitor
Luminance Signal : 1Vp-p/75 Ω
Color Signal : 0.286Vp-p/75 Ω
Luminance signal frequency characteristic 10 Hz to 10 MHz + 0 -1dB
Signal-to-noise ratio 60 dB or more
<General>
Power supply voltage 100 VAC, 50Hz/60Hz
AC outlet Power switch interlock : 2 systems (150W)
Power switch not linked : 1 system (100W)
Power consumption (Electrical Appliance and Material Control Law) 230W
External dimensions Width 420x Height 162x Depth 435 mm
Weight 15kg