Audio Database

Image of Integra A-917
Commentary

Pre-main amplifier released as the new Integra series in the 90's.

A "Current Drive Amplifier", a current amplifier, is mounted on the output stage and a "BI-MOS Drive System" is combined into a super current amplifier structure.

The current drive amplifier takes note of the fact that the important process of "voltage to current" conversion is carried out by the output stage transistor of the conventional amplifier with drastic temperature change. The current drive amplifier is composed so that "voltage to current" conversion is completed in the previous stage of the output stage, and the output stage only amplifies the current.
This allows current amplification in an extremely stable state without being affected by the heat generated by the output transistor.
The BI-MOS drive system brings out the advantages of a MOS FET and a bipolar transistor. As the input voltage increases, the MOS FET exhibits a gentle rising curve in the low-current region, while in the high-current region, the stretch and linear characteristics of the bipolar transistor become dominant.
As a result, almost linear characteristics can be obtained in the crossover region, and linearity with elongation even at large amplitude is realized.
The super current amplifier has a structure that adopts a BI-MOS drive system that converts voltage to current at the front stage of the output stage.

All stages constituting the power amplifier are push-pull specifications with perfect symmetry between the + side and the side to suppress asymmetrical distortion of the waveform.

The LASER transformer originally developed by Onkyo is used as the power transformer.
The newly developed LASER transformer employs a new type of conversion core with a wider outer circumference than the standard one. This is a result of focusing on the fact that the magnetic leakage from the outer circumference reduces electric resistance by widening the outer circumference. The ratio of the outer circumference to the center 2 was previously 1, but the width of the outer circumference is widened from 1 to 1.07 in the LASER transformer.
In addition, the core is carefully shielded by silicon steel plate shielding material, and as a result, leakage flux is reduced to 1 / 30 compared with conventional EI transformers.

The chassis structure adopts a 2-box 2-division bottom chassis structure with the power supply and other stages separated.
In addition, the power stage and small signal section are divided into blocks by a heat sink to guard against interference to the small signal section.

The secondary winding of the power transformer is separated and independent for power amplifier and protector circuit. Sub-transformers are mounted for microcomputer and display to supply power independently to each stage, eliminating interference between each stage.

In order to reproduce all music signals with high purity, we have adopted a simple direct design that sends signals directly to the power amplifier via a dedicated volume.
When the source direct switch is set to DIRECT, simple transmission is possible, and when the position is set to TONE, direct tone adjustment is possible.

Equipped as standard with a remote control function that allows you to perform power supply, volume, input selector and muting from your hand.
Since the volume and input selector employ a motor-driven mechanical system, there is no nonlinear distortion that occurs in semiconductor switches.

The capacitor in the power supply section is firmly fixed by a new type of Chemi-Con damping structural material.

The bottom chassis is coated with PVC to reduce vibration.

High-speed diode, AC cord with polarity display, and die-cast and detent volume are adopted.

The side panel is a BMC side panel.

Model Rating
Type Super current amplifier with LASER transformer
Rated output (20 Hz to 20 kHz
CD → SP-OUT, both channels driven)
100W + 100W (6 Ω)
80W + 80W (8 Ω)
Dynamic Power 2 Ω : 265W + 265W
4 Ω : 205W + 205W
6 Ω : 150W + 150W
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 -0.3 dB
Phono maximum allowable input
(1kHz/10kHz, 0.005%)
MM:150mV/710mV
MC:9mV/42mV
Input Sensitivity / Impedance Phono MM : 2.5mV/47k Ω
Phono MC : 160 μ V/220 Ω
CD, Tape Play, Processor IN, etc. : 150mV/30k Ω
Rated output voltage / impedance Tape Rec, Processor Out, etc. : 150mV/560 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 (20 Hz)
Treble : ± 8 dB (20 kHz)
Muting -20dB
Pwer 100 VAC, 50Hz/60Hz
AC outlet Switched : 2 systems, 100W
Unswitched : 1 line, 100W total
Power consumption (Electrical Appliance and Material Control Law standard) 190W
External dimensions Width 455x Height 170x Depth 430 mm
Weight 17.0kg
Attachment Remote control