ONKYO Integra A-819
¥ 95,000 (around 1981)
Commentary
A stereo pre-main amplifier that adopts the W super servo system.
The W Super Servo System uses a purely electronic method using a servo circuit to suppress noise components by more than 40 dB. At the same time, it cuts out harmful ultra-low frequency components that cause intermodulation distortion, improving resolution and other features.
Linear switching method is adopted for amplification at the final output stage.
In this method, two transistors are used, and a special bias circuit is used to compensate for the connection of operation characteristics that causes crossover distortion.
In additionTBy adopting a 3-stage Darlington configuration of power transistors and a push-pull circuit, the effect of switching distortion is kept within a negligible range.
It uses a high-gain equalizer amplifier that can handle the input from the MM cartridge and the weak input from the MC cartridge.
In addition, the tone amplifier and buffer amplifier are eliminated, and a two amplifier configuration directly connected to a power amplifier based on the W / Super Servo system is adopted to increase the purity of sound.
The direct tone method is used for tone control.
By using a passive element that does not affect sound quality, it is possible to adjust sound quality at higher quality.
There is a soft circuit that makes it easier to hear low-quality signals.
The power supply section employs a large power transformer and low-impedance wide-range Chemi-Con is directly connected to a printed circuit board to reduce inductance.
In addition, copper plates and bus (bus) lines are used at important points such as the power supply and distribution to each section and the ground line to ensure low impedance.
In order to prevent unstable bias fluctuation due to temperature difference caused by heat capacity difference between each block due to sudden change of signal, an auto tracking bias circuit is adopted which automatically controls bias by detecting temperature difference between three parts of pre-driver, driver and power transistor.
Sound quality priority design using non-magnetic material to suppress the generation of higher harmonics.
Equipped with a Pre Out jack that can record control signals.
Model Rating
| Type | W super servo type pre-main amplifier | ||||
| Rated Output (Aux → SP out) | 90W + 90W (20 Hz to 20 kHz, 8 Ω, both channel drive) | ||||
| Total harmonic distortion rate (20 Hz to 20 kHz) | 0.015% / 0.012% (AUX → SP Out, at rated output / at 1/2 output) 0.003% (Phono MM → Rec Out, 3 V) 0.015% (Phono MC → Rec Out, 3 v) |
||||
| Intermodulation distortion factor (Aux → SP out) | 0.008% | ||||
| Powerbandwidth | 5 Hz ~ 100 kHz (Aux → SP out) | ||||
| Damping factor | 100 (1 kHz, 8 Ω) | ||||
| Frequency characteristic |
|
||||
| Input Sensitivity / Impedance | Phono MM : 2.9mV/47k Ω -100k Ω Phono High MC : 2.9mV/100 Ω Phono MC : 180 μ V/100 Ω -330 Ω Tuner, AUX, Tape Play1, 2 : 150mV/47k Ω |
||||
| Phono maximum allowable input (1kHz/10kHz, 0.05%) |
Phono MM:250mV/1200mV Phono High MC:250mV/1200mV Phono MC:17mV/82mV |
||||
| Output Voltage / Impedance | Tape Rec1, 2 : 150mV/2.2k Ω Pre Out : 1.5V/600 Ω |
||||
| S/N ratio (IHF A-short) | Phono MM:87dB Phono MC:69dB Tuner, AUX, Tape Play1, 2 : 100 dB |
||||
| Tone Control (Vol-16dB) | Bass : ± 8 dB (70 Hz) Treble : ± 8 dB (20 kHz) |
||||
| Loudness | +6dB(100Hz) | ||||
| Subsonic filter | 15Hz/20Hz, 6dB/oct. | ||||
| Muting | -20dB | ||||
| Pwer | 100 V, 50/60Hz | ||||
| Power consumption | 150W (Electrical Appliance and Material Control Law Standard) | ||||
| AC outlet | Unswitched-1 (200W) Switched : 2 (total 200W) |
||||
| External dimensions | Width 435x Height 142x Depth 385 mm | ||||
| Weight | 12kg |