ONKYO Integra A-1E

Commentary

The pre-main amplifier of the QUEST series was developed and designed with the concept of quality, and introduced high quality materials and high quality parts.

In order to achieve excellent DC performance, the differential amplifier of the first and second pre-drive stages employs a high-precision dual transistor for measuring instruments, and the main part from the pre-drive stage to the final output stage employs a high-precision resistor with an error of ± 0.1% to achieve a stable circuit configuration.
By reexamining the circuit design and the phase compensation method, it was possible to reduce the negative feedback amount of the overall and also succeeded in eliminating the filter coil of the output part, which is one of the causes of sound quality degradation.
This eliminates the influence of electromagnetic coupling with other circuits, and makes it possible to prevent an increase in output impedance in the high frequencies.
By incorporating the output relay into the negative feedback loop, the equivalent linearity of the contact section is improved.

We have developed a new real-time temperature compensation circuit for output transistors to minimize the degradation of sound quality caused by bias fluctuations due to changes in loads and music signals.
In this method, a two chip dual transistor is used, one of which monitors the loss of the output transistor, and the other detects a proportional temperature change and controls the bias.
Since this method cannot be used for a large output amplifier due to the limitation of the control element used, the rated output is set to 50W. However, the linearity at low load is improved by using a Pc = 80W transistor for the output stage to increase the current margin.

The power transformer is equipped with a newly developed toroidal type LASER transformer, which realizes small size, large capacity and low leakage flux characteristics taking advantage of the high efficiency characteristics of the toroidal type.

The chassis uses a 9 mm thick non-magnetic all-aluminum extrusion molded monocoque chassis on the front panel. With the latest high-precision machining technology, it has a high-precision finish with an error of ± 0.5 mm.
By providing many ribs on the inner and outer surfaces, chassis rigidity is improved and unwanted resonance is reduced.
In addition, the transformer, heat sink, and printed circuit board are mounted in isolation with the chassis using an insulator to ensure high rigidity and no resonance.

High-precision and high-quality parts have been introduced. In addition to high-precision dual transistors for measuring instruments and high-precision resistors with an error of ± 0.1%, which are used for differential amplification, ultra-low-distortion volume, film conditioners manufactured by Raderstein of Germany, and low-impedance, 70 μ m copper foil printed circuit boards that are twice as thick as conventional ones, all have been used for high sound quality.

Model Rating

Type	Pre-main amplifier
Rated output	50W + 50W (8 Ω) 85W + 85W (4 Ω)
Dynamic Power	80W + 80W (8 Ω) 140W + 140W (4 Ω) 230W + 230W (2 Ω)
Total Harmonic Distortion Factor (20 Hz to 20 kHz, 8 Ω)	0.02% (at rated output) 0.01% (at 10W output)
Intermodulation distortion factor (70 Hz : 7 kHz = 4 : 1, 8 Ω)	0.02% (at rated output)
Powerbandwidth	10 Hz to 100 kHz (IHF-3dB, THD 0.2%)
Damping factor	400 or More (8 Ω, 20 Hz to 20 kHz)
Slew rate	80 v / μ s
Frequency characteristic	10 Hz ~ 100 kHz + 0 -1.5 dB
S/N ratio (A-Weighted, input short)	CD:106dB
Channel separation	75 dB (CD, 1 kHz-terminated, 100 Hz to 10 kHz)
Input Sensitivity / Impedance	CD, Tuner, Line1, 2, Tape Play : 150mV/25k Ω
Recorded output	Tape Rec Out:150mV
Power consumption (Electrical Appliance and Material Control Law standard)	155W
External dimensions	Width 435x Height 85x Depth 374 mm
Weight	9.1kg