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ONKYO Integra P-855NII
95,000yen(1975 release)

Description
 
The preamplifier which added the study fundamental about a feeling of a lateralization in an inside bass region etc., and it not only develops further the measure against a transient response in an equalizer circuitry, a tone circuitry, etc. which have been developed in the Integra serieses, and a modification of a dynamic behavior, but raised completeness.

The dual channel scheme independent source which made the powering to each channel on either side become independent is adopted.
This loses the cross interferencee between the channels inside a preamplifier, and the separation is raised.
The power-source part has adopted the feedback stable type±2 power-source scheme voltage stabilizer whose regulation is 1.7%, and it is considered so that the influence of a power supply variation may not come out to the circuitry which performs a delicate voltage amplification.

The transient response property is improved by using for an equalizer amplifier circuitry the OP-amp type circuitry of one step of differential, and a final-stage single 4 stone stream composition borne by the detailed theoretical analysis to NF circuitry.

The OP-amp type circuitry of the 1 step of differential 3 stone stream composition for which it opted from the circuit analysis by computer using is adopted as a tone amplifier circuitry, and many measures, such as selection of the optimal time constant, reservation of the dynamic range in an open loop, and a modification of an SN ratio, are taken.
Thereby, although the transition was conventionally given to the riser property of the important inside bass region with various members including NF circuitry, this has been improved and the good circuitry of a riser is realized irrespective of tone ON-OFF.

In order to prevent the it1 at the time of switchpoint ON-OFF, the transient killer circuit which uses a reed relay is adopted.

The film capacitor of a unguided extended foil structure, and super-low leakage and a special electrolytic capacitor are adopted as the coupling capacitor which has big influence on play sound.

The precision trimming attenuator volume of an interlocking error of ±0.5dB is adopted as a coordination of a volume and a tone, volumes are 43 contacts (an intermediate position is also possible), and ±five steps of coordinations of a 2dB step are possible for a tone.

Since the input of equalizer amplifier is monitored, the peek monitor by light emitting diode is built in, and the clipping point of an equalizer input can be monitored.

The loudness is Low and the two-step change of Low&High.

Rear
The

Rating of a mode
Form Preamplifier
Input sensitivity/impedance Phono1:1.2, 2.4, 4.8mV/100, 50, 30kohm
Phono2:1.2, 2.4 or 4.8mV / 50kohm
Tuner, AUX1, 2, Play:100mV /, 50kohm
THD (at the time of 1V output 1kHz) 0.01%
Cross modulation distortion 0.05% or less (at SMPTE, the time of 1V output 70Hz:7kHz=4:1)
RIAA property (Phono1, 2) Less than 30Hz-15kHz±0.2dB
Less than 20Hz-20kHz±0.5dB
Frequency characteristic
(Tuner, AUX1, 2, Play)
15Hz-70kHz+0 -0.5 dB
10Hz-100kHz+0 -1.0 dB
Phono maximum permissible input
(2.4mV, T.H.D.0.1%)
1kHz(R.M.S.)
10kHz(R.M.S.)
S/N (IHF-A network)
Input shunt
Phono1, 2:75dB or more
Tuner, AUX1, 2, Play: 90dB or more
An Output voltage/impedance Output(at the time of a 100kohm load intensity): 1V (rate), 10V (maxima)/600ohm
Rec Out(Phono): 100mV (rate) / 12kohm
Tone control (2dB step type) Treble: ±10dB (10kHz and F.Shift 2kHz o'clock)
Bass: ±10dB (100Hz and F.Shift 400Hz o'clock)
Turnover frequency Treble: 2kHz, 8kHz, Defeat
Bass: 400Hz, 125Hz, Defeat
Loudness (volume 30dB location) + 5dB (70Hz), +3dB (10kHz)
Light filter High-Cut: 5kHz, 20kHz, 6dB / oct
Low-Cut: 50Hz, 10Hz, 12dB / oct
Muting - 10dB-20dB
Input/output polarity EQ-AMP: Inphase
Tone+Buffer-Amp: Inphase
Transient killer operating time At the time of SW-ON: About 7 seconds
At the time of SW-OFF: Start from 0.5 second.
The semiconductor used Transistor: 37 pieces
Diode: 40 pieces
light emitting diode: One piece
Power source AC100V, 50Hz/60Hz
AC output Switched: Three lines
Unswitched: One line
Four line total: 1100VA