ONKYO Integra A-819RX
¥ 119,000 (released in 1984)
Commentary
This is a real phase stereo pre-main amplifier with in-phase transformer to improve the phase shift.
The amplifier supplies the speaker current according to the input signal (voltage). However, since the impedance changes suddenly near the fo of the speaker, a phase shift of approximately ± 90 ° occurs between the input signal and the speaker current. This out-of-phase speaker current is sent from the power supply through the current amplifier section of the amplifier. In conventional amplifiers, it affects the voltage amplifier section and disturbs the upper phase of the music signal.
To solve this problem, we added Onkyo's unique power in-phase transformer to the power supply, which is the source of the speaker current, and adopted a double transformer drive system that drives with two transformers, eliminating the voltage generated by the phase shift of the speaker current.
This power-in-phase transformer has a high coupling degree of K = 0.99. It combines the charge current with the opposite phase of + - and creates a charge current with a constant peak. This eliminates out-of-phase information from the charge current and transmits correct phase information.
A power-in-phase transformer eliminates common-mode noise.
In a power-in-phase transformer, the charging current on the positive and negative sides is at the same level with a constant peak, so no current flows between the transformer midpoint and the ground. Furthermore, the transformer midpoint is grounded, so common-mode noise is bypassed through the ground line and does not adversely affect sound quality.
All the circuit technologies developed in the Integra Series have been adopted, and the quality has been improved by installing a double sensing servo system that uses a servo amplifier from both + - terminals of the speaker for servo feedback, a two amplifier configuration consisting of a high-gain equalizer and a power amplifier, and a direct tone circuit.
Along with the low impedance of speakers, we have adopted a power supply with a margin and a parallel-connected power transistor so that instantaneous values of 2 to 3 Ω will not be a problem.
Equipped with a charge noise filter to block power supply noise.
Uses a low-distortion linear switching system that realizes the distortion characteristics equivalent to class A.
Compatible with low impedance MC cartridge.
A super stabilizer is adopted to eliminate the adverse effect of external vibration.
Model Rating
Type | Stereo pre-main amplifier |
Rated output (20 Hz to 20 kHz Aux → sp out, both channels driven) |
125W + 125W (6 Ω) 110W + 110W (8 Ω) |
Total harmonic distortion rate (20 Hz to 20 kHz) | Aux → sp out : 0.005% (8 Ω at rated output) Phono MM → rec out : 0.003% (3 V) Phono MC → rec out : 0.015% (3 V) |
Intermodulation distortion factor (20 Hz to 20 kHz) | Aux → sp out : 0.004% (at rated output) |
Powerbandwidth | 5 Hz to 100 kHz (IHF-3dB, THD 0.2%, 8 Ω) |
Damping factor | 100 (1 kHz, 8 Ω) |
Frequency characteristic | Phono → rec out (RIAA deviation) : 20 Hz to 20 kHz ± 0.2 dB Aux → sp out : 2 Hz to 100 kHz + 0 -3dB |
Input Sensitivity / Impedance | Phono MM : 2.5mV/47k Ω, 100k Ω Phono high MC : 2.5mV/100 Ω Phono MC : 180 μ V/100 Ω, 220 Ω CD, tuner, aux, tape play : 150mV/47k Ω |
Phono maximum allowable input (1kHz/10kHz, 0.05%) |
phono MM:210mV/1000mV phono MC:15mV/82mV |
Rated output voltage / impedance | Tape rec1, 2 : 150mV/560 Ω |
S/N ratio (IHF-A filter input short) | phono MM:88dB phono MC:70dB CD, tuner, aux, tape play : 100 dB |
Tone Control (Vol-16dB) | Bass : + / - 8 dB Treble : + / - 8 dB |
Loudness | +6dB(100Hz) |
Subsonic filter | 15 Hz, 6dB/oct. |
Muting | -20dB |
Pwer | 100 VAC, 50Hz/60Hz |
Power consumption (Electrical Appliance and Material Control Law standard) | 220W |
AC outlet | Unswitched : 1 line, 200W Switched : 2 systems, total 200W |
External dimensions | Width 465x Height 158x Depth 391 mm |
Weight | 15.5kg |