Audio Database

The pictorial image of Integra P-309

ONKYO Integra P-309
250,000yen(around the 1983 time)

The stereo preamplifier developed as a compilation of "W and the super servo scheme" into which the "super servo scheme" was developed further.

The gain up of equalizer amplifier is aimed at so that man-month type to MC type can respond to all the cartridges, without Onkyo using head amplifier and a step amplifier transformer taking advantage of the property of the super servo scheme developed uniquely.
Let three units of MC head amplifier, an equalizer, and a buffer collectively be the simple equalizer amplifier of 1 stage scheme,The large-current first class amplifier which is equal to output 5W class power amplifier is adopted, and the NF-CR splitting type equalization is realized in one step without buffer amplifier.
In the first rank differential-amplifier part, the heat joint treatment of two a super-low-noise and High Gm FET is carried out in an aluminum case, and visitor thermal noise is suppressed with the thermal balance modification. Moreover, a differential part is made the Para interconnection and the improvement in S/N is aimed at by lowering an impedance. In order that this differential amplifier may stop a mirror feedback capacity, it was made the cascode interconnection and has aimed at the expansion of the frequency characteristic.
Moreover, big nakedness gain was secured by the 2nd step differential amplifier and the differential amplifier with the 3rd step current mirror, and the stability and the constant distortion are realized by using a partial feedback according it to a skillful pole setups.

The weighting monitor is carried in the panel side.
This monitor detects the first class push pull transistor of an equalizer final stage, and the temperature of the transistor currently used for the power-source part of an equalizer, and shows the stability of the bias after Power ON, and the operating state of amplifier with the indicator which shines to five steps.

In order to prevent a part for an inductance, a resisted part, contact resistance, a crosstalk in a terminal area that an extension cord has, W and a super servo scheme are adopted.
W and the super servo scheme which cancels in equivalent the harmful noise component which suppresses the cross modulation by unnecessary super-low-pass one, and originates in the impedance between groundings,By using an attached servo sensor code, distance between a pre and power was electrically made into zero, and the harmful component is canceled.

The direct tone which is an original tone control scheme which does not affect a tone quality is adopted.
It consists of only passive elements, and since it is a scheme into which a capacitor harmful in a signal passage path does not go, a sound field correction can be performed freely, without affecting a tone quality.

Although the problem of low-pass running short extremely tended to occur when the low power amplifier of an input impedance was connected or the parallel drive of two or more power amplifier was carried out,Since it is not necessary to put a capacitor into an output fraction by adopting a super servo scheme and a low-pass time constant is determined only in a servo circuitry, it has prevented shortage occurring in low-pass regardless of the load intensity.

About the power source, while making the power source of a right-and-left channel become independent completely and supplying it, in order to prevent the interference which leads the power source in the order stage also within the same channel, low-impedance-ization of the whole power-feeding system is attained and the occurrence of the dynamic modulation (transitional cross modulation distortion) is suppressed.
In IntegraP-309, while using NF type constant-voltage stable circuitry which achieved the right-and-left independency, each circuitry block is directly linked with the plate-mill bus (bus-bar) line made from a copper plate.

According to the cartridge which carries the cartridge selector and is used, the change of the optimal load impedance is possible.

Also when not recording by carrying the recording selector, it is considered so that the deck may not remain always connected to a part of circuitry.
Moreover, it is also possible to record a tuner output, hearing a record.

Headphone amplifier is built in so that a using of headphone can be performed.

Various filters, a muting, an input selector, etc. are accommodated in a kangaroo pocket.

From the first, a shielding part uses non-magnetic material, such as copper, aluminum, and a brass, for required component partses altogether, and is suppressing high order higher-harmonic distortion generated under the influence of magnetic flux until it results in each part article.

The one-touch selector of an illuminaned button switch is adopted as the change of an input.
Moreover, the scheme selected by low-profile special audio relay is adopted, and the signal system product line is not taken about.

The thermostat coupled register is carried, and the register who acted as a couple of the heat fator is used so that the delicate servo effect may always start stably to a signal.

A Super

Rating of a mode
Form W super servo scheme stereo preamplifier
Input sensitivity/impedance Phono MC: 130 microvolt/100ohm, 330ohm
Phono High Gain MC: 2.5mV/100 ohm
Phono man month: 2.5mV / 47kohm, 100kohm
Tuner, AUX, Tape Play:150mV /, 47kohm
An Output voltage/impedance Tape Rec: 150mV / 2.2kohm
Output: 1.5V, a maximum of 13V/220ohm
Phono maximum permissible input (THD 0.05%, 1kHz) MC:19mV
man month, High Gain MC: 380mV
Frequency characteristic Phono MC: 4Hz-150kHz+0.2 -3dB
Phono man month: 1.8Hz-170kHz+0.2 -3dB
Tuner, AUX, and Tape:0.8Hz-170kHz+0 -3 dB
THD (THD, 20Hz - 20kHz, output 3V) Phono MC (Volume-30dB): 0.008% or less
Phono man month (Volume-30dB): 0.002% or less
Tuner, AUX, Tape: 0.002% or less
Cross modulation distortion (SMPTE 70Hz:7kHz=4:1) 0.003% or less (at the time of an Output power)
S/N (an IHF-A network, an input shunt) Phono MC:70dB
Phono MM:88dB
Tuner, AUX, Tape: 100dB
Tone control (Volume-20dB) Bass: 70Hz, ±8dB
Treble: 20kHz, ±8dB
Filter High Cut Filter: 7kHz, 6dB / oct
EQ Subsonic Filter: 15Hz/20 Hz, 6dB / oct
Muting -20db
Transient killer operating time Power on/off:7sec/100msec
The semiconductor used Transistor: 71 pieces
FET: Ten pieces
IC: Eight pieces
Diode: 50 pieces
Supply voltage AC100V, 50Hz/60Hz
AC output Power-source interlock: Two lines
Un-interlocking.: Two lines
Total 1000W (maxima)
Power consumption (Electrical Appliance and Material Control Law) 65W
Dimensions Width 476x height 122x depth of 415mm
Weight 10.5kg