ONKYO Integra A-722mkII/150

Commentary

This pre-main amplifier is the top model of the MKII series, and is intended to improve sound quality by clarifying problems in the tone amplifier section.

A wide dynamic range source for the equalizer's allowable input, it is compatible with sources with a wide dynamic range.

In tone amplifiers, various elements, including the NF circuit that controls tone characteristics, change the rise and fall characteristics of middle and low frequencies, which adversely affect sound quality. This part of the MKII series that had been overlooked in the past has been thoroughly clarified by computer simulation and various problems have been solved.
In the tone amplifier, a variable β circuit is inserted in the NF circuit to give tone characteristics, and it has four time constants in the ultra-low frequency range. If this time constant is not carefully selected, a flat amplifier with excellent feedback stability cannot be realized. In the MKII series, a circuit that is advantageous to ensure feedback stability in a sufficiently low frequency range is selected and adopted, and a stable circuit with a large phase margin is realized.
In addition, in order to keep the high-pass cutoff high with a simple circuit while taking into consideration the balance between the high-pass and low-pass, and to ensure sufficient dynamic range even with a simple configuration, we have adopted a unique 2-stage circuit with a differential 1-stage emitter grounding.

In order to improve the signal-to-noise ratio, we have selected a PNP type transistor for the tone amplifier section, which has less 1/f noise due to its structure, and set the impedance level at the best point of the noise characteristic of the transistor.

In order to eliminate adverse effects of power supply voltage fluctuations, a differential circuit is used for the tone circuit, which is less affected by voltage fluctuations. In addition, the voltage is supplied through a ± 2 power supply type low voltage circuit with a voltage fluctuation rate of 1.7%, which prevents intermodulation due to voltage fluctuations in the power amplifier section.

Pure complimentary service with improved transient response characteristics in all stages Technologies developed in the conventional Integra series, such as power amplifiers with all stages connected directly, and operational amplifier type equalizer circuits, have also been introduced.

Model Rating

Type	Pre-main amplifier
Power Amplifier Unit
Rated Output (1 kHz)	8 Ω : 75W + 75W 4 Ω : 90W + 90W
Dynamic Power (IFF8 Ω)	240W
Total Harmonic Distortion Factor (T. H. D., 1 kHz)	0.1% or Less (at Rated Output) 0.03% or less (at 10W output) 0.03% or less (at 0.5W output)
Intermodulation Distortion Factor (S. M. P. T. E, 70 hz : 7 khz = 4 : 1)	0.05% or Less (at Rated Output)
Power Band With (IHF, -3dB, THD 0.3%)	10 Hz to 100 kHz
Signal-to-noise ratio (IHF A network, input shunt)	110 dB or more
Damping factor (DC ~ 20 kHz)	8 Ω : 80 4 Ω : 40
Load impedance	4 Ω ~ 16 Ω
Gain	28dB
Output terminal	Speaker : A, B, C, A + B Headphone jack
Preamplifier Section
Input Sensitivity / Impedance	Phono1 : 1.2 mV, 2.4 mV, 4.8mV/50k Ω, 30k Ω Phono2 : 1.2 mV, 2.4 mV, 4.8mV/50k Ω Tuner, AUX1, 2, Play : 100mV/50k Ω
Total Harmonic Distortion Factor (1 v, 1 khz)	Not more than 0.03%
Intermodulation Distortion Factor (1 v, S. M. P. T. E, 70 hz : 7 khz = 4 : 1)	Not more than 0.05%
RIAA deviation (Phono1, 2)	20 Hz to 20 kHz ± 0.5 dB
Phono maximum allowable input (1kHz/10kHz, THD 0.1% (R. M.S.))	Input sensitivity 4.8 mv : 600mV/2700mV Input sensitivity 2.4 mv : 300mV/1400mV Input sensitivity 1.2 mv : 150mV/700mV
S/N (IHF A network, input shunt)	Phono1, 2 : 75 dB or more Tuner, AUX1, 2, Play : 90 dB or higher
Output Voltage / Impedance	Pre Out (at 100k Ω load) Rated output : 1V/2.7k Ω Maximum output : 4V/2.7k Ω Rec Out(Phono) Rated output : 100mV/12k Ω
Tone Control (2 db Step Type)	Treble : ± 10 dB at 10 kHz, F-Shift 2 kHz Bass : ± 10 dB at 100 Hz, F-Shift, 400 Hz
Turnover frequency	Treble : 2 khz, 8 khz, Defeat Bass : 400 Hz, 125 Hz, Defeat
Loudness (at volume -30dB)	+5dB(550Hz) + 5 dB at 70 Hz, + 3 dB at 10 kHz
Filter	High-Filter : 5 kHz, 20 kHz, 12dB/oct. Low-Filter : 10 Hz, 30 Hz, 12dB/oct.
Muting	-10dB/-20dB
<General>
Semiconductor used	Transistor : 52 Diode : 36 units
Pwer	100 VAC, 50Hz/60Hz
AC Output	Switched : 2 systems, 200 VA Unswitched : 1 line, 200 VA
Power consumption	Electrical Appliance and Material Control Law Standard : 160W Maximum power consumption : 400W
External dimensions	Width 446x Height 161x Depth 386 mm
Weight	14.5kg