Audio Database

Image of Integra M-506
Commentary

A stereo power amplifier that adopts the W / Super Servo system.

The W / Super Servo system is used to cancel the feedback of harmful components from both the + side and - side of the output terminal via the servo amplifier.
The + side cancels the ultra-low frequency component that is superimposed on the music signal and flows into the speaker to suppress harmful intermodulation. The - side servo loop suppresses the electromotive force caused by the impedance between the input ground and the output ground side, the internal resistance of the power supply capacitor, the impedance of the lead wire, etc., and only the music signal is sent to the output terminal.
By servocontrol both ends of the output side, the components of impurities, harmful noise and distortion that have masked the music signal are eliminated to improve the resolution.

Output stage is 3-stage Darlington configuration, high-fTBy using a power transistor, an output with less distortion is achieved. In addition, the operating characteristic of the power transistor is Onkyo's unique linear switching method to further improve the distortion factor.
This system was developed with the intention of taking advantage of the characteristics of A class while taking advantage of the advantages of B class, focusing on the fact that only the final output stage works as B class in amplifiers. It is a system with linear characteristics developed under the design policy that bias must be fixed. It is a high-f type system with linear characteristics.TIt demonstrates excellent performance when combined with a power transistor.

As a result of research on the influence on sound quality, we have newly developed a large twin-winded transformer for the power supply section. As a result of careful listening and investigation of the correlation between material properties in consideration of its importance, we have used a multi-tab type low-impedance wide-range Chemi-Con as a low-inductance circuit directly connected to a printed circuit board.
In addition, bus (bus) lines are used for the power supply / distribution to each section and the ground line, etc. to achieve a thorough low impedance.

When there is a sudden change from a continuous large amplitude operation to a small amplitude operation, a thermal gradient occurs due to the difference in heat capacity between the final blocks. This sudden partial temperature change makes the bias current value of the power section unstable and affects the reproduction of a low-level signal in particular.
As a countermeasure against this problem, the M-506 has a 3-point sensing bias circuit in the output stage, detects the temperature difference between the pre-driver, driver and power transistor, and controls the bias, ensuring stable low-distortion drive.

The protection circuit uses a monolithic IC to improve stability. It also detects DC leakage voltage at the speaker terminals and overcurrent in the power stage. In the event of an emergency, it instantly shuts off the relay (silver contact, parallel use) to protect the circuit components.
For speaker switching, the protection relay dedicated to SP-1 and SP-2 is switched to prevent degradation of the damping factor. Also, the low-pass filter for DC voltage detection is independent of LR so that it operates even when the polarity of the left and right is different.

It employs a large peak meter that performs logarithmic compression and peak hold with a stable monolithic IC.
In addition, to obtain high-speed response, it is driven by a dedicated drive circuit using an operational amplifier.
The level can be changed from 0 dB to 120W or 12W with the front switch.

From semiconductor devices and transformers, to resistors and capacitors, printed circuit boards, lead wires for wiring, to solder for fusion bonding, we have repeatedly conducted thorough examinations through interviews.

Model Rating
Type W / Super Servo Type Stereo Power Amplifier
Amplifier Unit
Effective output (20 Hz to 20 kHz) 160W + 160W (4 Ω)
120W + 120W (8 Ω)
Dynamic Power (1 kHz) 180W + 180W (8 Ω)
Total Harmonic Distortion Factor (THD, 20 Hz to 20 kHz) 0.003% or Less (Effective Output)
0.003% or Less (at 60W Output)
Intermodulation distortion factor (SMPTE70Hz : 7 khz = 4 : 1) 0.003% or Less (Effective Output)
Power Band Wiz (IHF-3dB, THD 0.2%) 5 Hz to 100 kHz
Gain 26.3dB
Frequency characteristic 1 Hz ~ 100 kHz + 0 -1.5 dB
Signal-to-noise ratio (IHF-A network input shunt) 120dB
Input Sensitivity / Impedance 1.5V/47k Ω
Speaker load impedance 4 Ω ~ 16 Ω
Damping factor (8 Ω, 1 kHz) 180
Output terminal Speaker System1, 2
Headphone
Transient killer operating time Power on:5sec
Power off:100msec
Meter Section
Range switching x1(0dB=120W)
x0.1(0dB=12W)
Indication range -40dB to + 4 dB
Indication accuracy 0 ± 1 dB
-10 + / - 2 dB
-20 + / - 3 dB
Response speed 100 μ sec (∞ → 0 dB)
Return speed 1 sec (0 dB → -20dB)
<General>
Semiconductor used Transistor : 47
FET : 2
IC : 6
Diode : 40 pcs
Pwer 100 VAC, 50Hz/60Hz
AC outlet Up to 600W
Power switch not linked : 1 system
Power consumption 190W (Electrical Appliance and Material Control Law)
Maximum external dimensions Width 450x Height 174x Depth 400 mm
Weight 18.5kg