ONKYO Integra A-817XG

Commentary

Pre-main amplifier that adopts BI-MOS drive amplifier.

The BI-MOS drive amplifier has an output stage for each of a MOS FET and a bipolar transistor, and drives a speaker by both of them. As the input voltage increases, the MOS FET rises first and then the bipolar transistor rises.
As a result, the BI-MOS composite characteristic shows the characteristic of the gentle rise curve of the MOS FET in the small current region, and the characteristic of the stretch and linear characteristic of the bipolar transistor becomes dominant in the large current region.
As a result, the overall + / - characteristics are very close to a straight line in the crossover region, and excellent linearity characteristics with elongation even in the large amplitude region are realized.

We have developed and adopted a laser transformer to prevent the power transformer from generating magnetic leakage flux and harmful noise caused by magnetic induction in the amplifier circuit.
This laser transformer uses a new type of EI core with a wider outer circumference than the standard one. This reduces the magnetic resistance of the outer circumference and makes it difficult for magnetic flux to leak from the core.
In addition, the area around the core is carefully shielded with silicon steel shielding material, and the area around the coil is also shielded to prevent flux leakage.
As a result, the leakage flux is reduced to 1 / 20 compared with the conventional EI transformer.

It comes standard with a wireless remote control that controls the input selector and volume at hand.
In addition, it uses a motor-driven mechanical system to suppress the occurrence of non-linear distortion like semiconductor switches and to prevent adverse effects on sound quality.

The video input / output jacks are installed Route 3 to enable Iori, recording, playback and BGV playback.

An optical drive and a current converter are used in the differential amplifier circuit at the first stage of the power amplifier circuit to obtain a stable reference voltage without fluctuation from the light energy produced by the photovoltaic element.
A voltage / current (V-I) conversion circuit using an operational amplifier generates a constant current and drives a differential amplifier circuit.
This suppresses unstable operation caused by fluctuation components due to music signals and power supply ripple fluctuations.

In order to eliminate interference between each stage and to realize pure signal transmission without causing unnecessary current to flow in the ground line between stages, the secondary winding of the power transformer is separated into power amplifier, EQ amplifier, microcomputer, etc.

The input, voltage amplification section and power amplification section are separated by sandwiching a heat sink. In addition, the power supply section and microcomputer section are also independent and shielded, and block separation construction is adopted which completely eliminates mutual interference.

In order to reproduce all music signals with high purity, it is equipped with a source direct switch that sends the source directly to the power amplifier via a dedicated volume.
When the position is set to TONE, it can be adjusted by direct tone, and when the position is set to Processor-TONE, it can be controlled by an external device such as a connected Gray.

The power supply Chemi-Con employs a large capacity, low impedance twin-roll Chemi-Con and high-speed diodes for all power supply rectifier diodes.
In addition, we use carefully selected parts such as die-cast detent type volume, gold-plated pin jack, large speaker terminal, and AC cord with polarity display.

Model Rating

Type	BI-MOS drive amplifier
Rated Output (20 Hz ~ 20 kHz)	100W + 100W (CD → SP Out, 6 Ω, both channel drive) 80W + 80W (CD → SP Out, 8 Ω, both channel drive)
Dynamic Power	2 Ω : 245W + 245W 4 Ω : 195W + 195W 6 Ω : 155W + 155W
Total harmonic distortion rate (20 Hz to 20 kHz)	0.0015% (CD → SP Out, at 10W output, 8 Ω) 0.003% (Phono MM → Rec Out at 3 v output) 0.015% (Phono MC → Rec Out at 3 v output)
Intermodulation distortion factor (20 Hz to 20 kHz)	0.004% (CD → SP Out, at rated output)
Powerbandwidth	5 Hz to 100 kHz (IHF-3dB, THD 0.2%, 8 Ω)
Damping factor	150 (1 kHz, 8 Ω)
Frequency characteristic	Phono → Rec Out (RIAA deviation) : 20 Hz to 20 kHz ± 0.2 dB CD → SP Out : 2 Hz ~ 100 kHz + 0 -3dB
Phono maximum allowable input	MM : 150mV/710mV (1kHz/10kHz, 0.005%) MC : 9mV/42mV (1kHz/10kHz, 0.005%)
Input Sensitivity / Impedance	Phono MM : 2.5mV/47k Ω Phono MC : 160 μ V/220 Ω CD, Tape Play, Processor IN, etc. : 150mV/47k Ω
Rated output voltage / impedance	Tape Rec, Processor Out, etc. : 150mV/560 Ω
Video input / output / impedance	VCR, Others : 1Vp-p/75 Ω
SN ratio (IHF-A filter input short)	Phono MM : 94 dB (5 mV input) Phono MC : 75 dB (0.5 mV input) CD, other : 107 dB
Tone Control Maximum Change	Bass : + / - 10 dB Treble : + / - 8 dB
Muting	-20dB
Pwer	100 VAC, 50Hz/60Hz
AC outlet	Switched : 1 system, 100W Unswitched : 2 lines, 100W total
Power consumption (Electrical Appliance and Material Control Law standard)	200W
External dimensions	Width 435x Height 161x Depth 394 mm
Weight	14.0kg
Attachment	Remote Controller RS 159 a