ONKYO Integra P-306R

Commentary

This is a Super Servo integral type preamplifier that uses a Super Stabilizer to dramatically improve sound purity and resolution.

The equalizer amplifier section uses an MC straight equalizer that takes advantage of the characteristics of Onkyo's unique Super Servo. It does not use an MC amplifier or step-up transformer and realizes a simple configuration of a bowl stage system that can be used for all cartridges.
The two low-noise and high-Gm FETs in the pre-stage operation amplifier section are thermally coupled in a special metal case to improve the thermal balance and suppress extraneous noise components.
In addition, in order to lower the impedance of the signal system and improve the overall SN, the operating part is connected in parallel. In order to obtain a wider frequency characteristic, the operating part is connected in cascode, and the mirror feedback capacitance is reduced.
The second stage differential amplifier and the third stage differential amplifier with differential amplifier with current mirror ensure a large naked gain, and with a handle with partial feedback by pole setting, excellent stability and low distortion factor are realized with high gain.
The final stage uses A-class push-pull to smoothly transmit signals to the next stage amplifier at a low distortion rate even under heavy loads in the high frequency range.

The newly developed Super Servo Integral System reduces the influence of the sound field and makes the electrical connection with the power amplifier smoother.
It is equipped with a super stabilizer to prevent microphonic noise generated inside due to mechanical vibration transmitted, and to prevent the reproduction sound from becoming muddy. The super stabilizer weighing approximately 3 kg is reinforced as a chassis structural material, and vibration resistance is improved by weight. By fixing each printed circuit board firmly to this stabilizer, vibration of the board itself is suppressed by internal absorption effect. In addition, the super stabilizer is made of a conductive layer made of special carbon particles. Space charge uniformity is measured and partial recombination is reduced, so high purity reproduction sound is obtained.
In addition, the Super Servo Integral Method eliminates the capacitor. The low-frequency time constant is determined only by the servo circuit. This prevents the low-frequency cut caused by the RC circuit between the capacitor and the input resistance when a general power amplifier is connected, and provides flat low-frequency characteristics.

To prevent degradation due to connection code between the preamplifier and the power amplifier, a Super Servo code is included. It suppresses cross modulation due to harmful ultra-low frequencies and equivalently cancels out unwanted components caused by impedance between the ground. The + input terminal of the output amplifier detects and suppresses harmful ultra-low frequencies, and the - input terminal of the output amplifier cancels out harmful components caused by the serious code, the resistance of the connection between the code and the power amplifier, the resistance of the code itself, inductance, etc., to prevent interference between channels and degradation of separation.
In order to eliminate the influence of the contact diode characteristics especially at the pin plug part, idle DC bias is superimposed on the ground line to suppress the daily wire diameter characteristics and reduce IM.
In addition, to confirm that the servo circuit works when the ground line is connected, the operation can be confirmed by the Connection lamp.

The power supply unit not only reduces interference between the left and right channels, but also prevents interference from the power supply between the pre-stage and post-stage channels. To this end, the entire power supply system is designed to have low impedance. Therefore, a high-speed response NF type constant voltage stabilizing circuit is used and each circuit block is directly connected by a bus line.

The tone control uses a direct tone system unique to Onkyo that is composed only of passive elements.

In order to prevent the magnetic flux generated from the circuit from generating high-order harmonics, mainly third harmonics, which are harmful to the sense of hearing due to the non-linearity of the magnetic path, all main parts are made of non-magnetic materials such as copper, brass, aluminum, and so on, avoiding iron materials.

Since the MC cartridge has various output voltage and output impedance, 3 types of cartridge selector are installed so that it can 10 Ω cartridge, 10 Ω ~ 40 Ω cartridge, and high output type cartridge so that it can always be used in optimum condition.

With a built-in recording selector, you can turn off the output or record a behind-the-scenes program when you don't record.

We analyze the component layout of the signal system in order to prevent crosstalk and characteristic degradation caused by lead wire routing.

In consideration of the effect of the resistor used on the sound quality, we use our own noise-improving resistor.
In addition to excellent frequency characteristics and strain characteristics, the conductor coating layer is designed to have uniform charge distribution and improved magnetic characteristics.

Model Rating

Type	Super Servo Integral Stereo Preamplifier
Input Sensitivity / Impedance	Phono MC : 130 μ V/100 Ω, 330 Ω Phono High Gain MC : 2.5mV/100 Ω Phono MM : 2.5mV/47k Ω, 100k Ω Tuner, AUX, Tape Play : 150mV/47k Ω
Output Level / Impedance	Tape Rec : 150mV/2.2k Ω Output : 1 v, max. 20V/220 ohm
Phono maximum allowable input (THD 0.05%)	MC: 17mV(1kHz) 82mV(10kHz) MM, High MC : 300mV(1kHz) 1400mV(10kHz)
Frequency characteristic	Phono MC : 4 hz to 150 khz + 0. 2-3 db Phono MM : 1.8 Hz to 170 kHz + 0.2 -3dB Tuner, AUX, Tape : 0.8 Hz to 170 kHz + 0 to 3 dB
Total harmonic distortion factor (THD, 20 Hz to 20 kHz Volume-30dB, output 3 v)	MC : not more than 0.008% MM : not more than 0.002% Tuner, AUX, Tape : 0.0015% or less
Intermodulation distortion factor (SMPTE70Hz : 7 khz = 4 : 1)	0.003% or Less (at Rated Output)
Signal-to-noise ratio (IHF-A network input shunt)	MC:69dB MM:86dB Tuner, AUX, Tape : 100 dB
Tone Control (Volume-20dB)	Bass : 70 Hz, ± 8 dB Treble : 20 kHz, ± 8 dB
Filter characteristic	High Cut : 7 kHz, 6dB/oct. Subsonic Cut : 15Hz/20Hz, 6dB/oct
Muting	-20dB
Transient killer operating time	Power on:7sec Power off:100msec
Semiconductor used	Transistor : 49 FET : 8 IC : 4 Diode : 37 pcs
Pwer	100 VAC, 50Hz/60Hz
AC outlet	Up to 1000W total Power switch interlock : 2 systems Power switch not linked : 1 system
Power consumption	26W (Electrical Appliance and Material Control Law)
External dimensions	Width 450x Height 99x Depth 403 mm
Weight	9.5kg