ONKYO Integra A-819GTR
¥ 108,000 (around 1982)
Commentary
A pre-main amplifier equipped with a super servo integral system and a delta turbo power supply.
We have developed and adopted the Delta Turbo Power Supply in order to obtain an effect close to the ideal power supply in the same size as the conventional one.
This reduces the generation of special intermodulation distortion in the power supply section, which adversely affects sound quality, by -20dB compared to conventional power supplies.
Super Servo Integral System is adopted in the amplifier section.
The electromotive force induced in the speaker by external factors such as sound pressure emitted from the reverse channel speaker is directly fed back to the amplifier by the microphone effect of the speaker. This electromotive force with a time difference as much as the sound travels through the space causes time difference distortion due to the linearity of the output stage of the amplifier.
This problem is reduced by a special linearity correction circuit compared with the conventional one.
In addition, the servo mechanism applied to the + - pole of the output side of the amplifier reduces harmful ultra-low frequency components and noise components that cause distortion due to the total impedance of the power supply.
In order to make the most of the performance of the MC cartridge, the GTR Series is equipped with a high-gain straight equalizer amplifier, which is designed mainly for high-quality MC playback, rather than merely adding a head amplifier or booster transformer.
In addition, the purity of sound is improved by a complete two amplifier configuration in which the tone amplifier and buffer amplifier are omitted and input directly to the high-gain power amplifier.
In addition, the final stage of the equalizer amplifier is class A push-pull so that the signal can be sent to the next stage with low distortion to cope with heavy loads in the high frequency range.
In addition, we examined the bare characteristics of both the equalizer and power to improve the overall linearity and adopt a low feedback system that is also effective in terms of audibility.
It uses a direct tone method which is an original tone control.
Since the tone amplifier, which had many problems in sound quality, is omitted and the tone is changed by using the loudness circuit related to volume control, the circuit is composed only of passive elements which have no problems in sound quality.
This reduces variations in sound quality.
Linear switching method is adopted for operation of output transistor.
There is no difference from class B in that two transistors are used, but the linearity of the joint of the operation curve, which is a problem, is corrected by a unique bias circuit to obtain always linear operation characteristics as a whole.
As a result, the crossover distortion is equivalent to class A amplification and the efficiency is class B.
High fTThe use of power transistors keeps switching distortion within a negligible range.
In addition to the shielding material of the circuit, all necessary parts are made of non-magnetic materials such as copper, brass and aluminum, avoiding the use of magnetic materials such as iron.
The cartridge selector is equipped with the MM2 system in the MC Route 3 so as to obtain the best matching.
The phono input pin jack is plated with pure gold to reduce the influence of contact resistance, etc.
All models are fully equipped with 5 levels of mode switching (Norm, Rev, R + L, L, R).
Built-in pre-out jacks allow you to record signals controlled by various filters and tones.
It is equipped with a softness switch that controls the resolution and makes it easier to quality sources.
In order to prevent the sound pressure reproduced from the speakers from shaking the amplifier circuit itself and making the reproduced sound muddy due to microphonic noise, the entire chassis structure is reinforced and a special super stabilizer is attached to the main pattern to absorb vibration.
Special noise-improving resistors with excellent frequency and distortion characteristics are used for important circuits.
Model Rating
| Type | Pre-main amplifier | ||||
| Rated Output (20 Hz ~ 20 kHz) | 100W + 100W (AUX → SP Out, 8 Ω, both channel drive) | ||||
| Total harmonic distortion rate (20 Hz to 20 kHz) | 0.008% / 0.006% (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) |
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| Intermodulation distortion factor (AUX → SP Out) | 0.008% | ||||
| Powerbandwidth | 5 Hz to 100 kHz (IHF -3dB, THD 0.2%) | ||||
| Damping factor (1 kHz, 8 Ω) | 100 | ||||
| Frequency characteristic |
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| 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 Play : 150mV/47k Ω |
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| Phono maximum allowable input (1kHz/10kHz, 0.05%) |
Phono MM:270mV/1300mV Phono High MC:270mV/1300mV Phono MC:17mV/82mV |
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| Output Voltage / Impedance | Tape Rec : 150mV/2.2k Ω Pre Out : 1.5V/600 Ω |
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| S/N ratio (IHF short) | Phono MM:88dB Phono MC:70dB Tuner, AUX, Tape Play : 100 dB |
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| Tone Control (Vol-16dB) | Bass : ± 8 dB (70 Hz) Treble : ± 8 dB (20 kHz) |
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| Loudness | +6dB(100Hz) | ||||
| Subsonic filter | 15 Hz 20 Hz, 6dB/oct. | ||||
| Muting | -20dB | ||||
| Pwer | 100 VAC, 50Hz/60Hz | ||||
| Power consumption (Electrical Appliance and Material Control Law standard) | 160W | ||||
| AC outlet | Unswitched-1 (200W) Switched : 2 (200W total) |
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| External dimensions | Width 465x Height 143x Depth 392 mm | ||||
| Weight | 15kg |