|ONKYO Integra P-306
|100,000yen(around the 1979 time)
The stereo preamplifier which adopted W and a super
W super servo scheme is a scheme which cancels in
equivalent the unnecessary component which suppresses the cross modulation by
unnecessary super-low-pass one, and originates in the impedance between
By using of an attached super servo code, the + side input
terminal of output amplifier detects and oppresses a harmful super-low-pass
component,Moreover, the servo amplifier by the side of - is canceling the
harmful component generated by a part for a resisted part of the connecting cord
with a main amplifier itself, or an inductance, contact resistance, etc., and
has prevented the interference and separation failure between channels.
In order to employ the property of a super servo efficiently, man-month
type to MC type has adopted the equalizer amplifier of the one stage scheme
corresponding to all the cartridges by the gain up of equalizer amplifier,
without the amplifier for MC also using a step-up transformer.
In the first
rank differential-amplifier part, the heat joint treatment of two
super-low-noise high Gm FET is carried out in an aluminum case, and visitor
thermal noise is also suppressed with the thermal balance modification.
Moreover, the improvement in S/N is aimed at by making the Para
interconnection of the differential part and lowering an impedance. In order
that this differential amplifier may stop a mirror feedback capacity, it was
made the cascode interconnection and has acquired the larger frequency
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 low distortion which were excellent in high gain
amplifier using the partial feedback by pole setups are realized.
Furthermore, the final stage is transmitting the signal to the following
stage amplifier by the low distortion by the Class-A push pull that there is no
unreasonableness also in the heavy load of a high region.
tone scheme is adopted as a tone control.
It consists of only passive
elements, and since it is a peculiar circuit system with which a harmful
capacitor does not enter in a signal passage path, a sound field correction can
be performed, without carrying out a tone-quality failure.
super servo scheme was adopted as output amplifier, an output capacitor did not
need to be put in, and since a low-pass time constant is determined only in a
servo circuitry, it has canceled the shortage of low-pass at the time of a
low-impedance load intensity.
It has linked each circuitry block
directly with the bus (bus-bar) line made from a copper plate, and has prevented
low-impedance-izing of a feed line, and the cross interferencee of each
inter-block while NF type constant-voltage stable circuitry which achieved the
right-and-left independency is used for a power-source part.
Non-magnetic material, such as copper, aluminum, and a brass, is used
for shielding material or each fraction.
Thereby, the magnetic flux
generated from a circuitry generated the high order higher harmonic (3rd higher
harmonic mainly harmful in Hearing impression) with the nonlinearity of the
magnetic path, and has prevented having an ill effect on a tone quality.
Since all cartridges are suited, the cartridge selector is carried.
The influence on the tone quality by a placement of each part, leading
about of a line, etc. is considered, and the placement analysis is conducted
later on in the order of a signal system.
For example, in order to input a
signal into a predetermined circuitry by a short-haul as much as possible, the
direct change by a remote-control switchpoint was adopted, and the failure of
the crosstalk by leading about of a signal line or a high region property is
The study and testing which were put into practice among all
the circuit component part were added, and the part which has a margin in all,
such as not only a property but an endurance, a feeling of a using, etc., is
For example, the input pin jack treating a weak electric current
gives a pure gold thickness plating, and consideration is carried out so that
the influence of contact resistance may not appear in a tone quality.
||W and a super servo scheme stereo preamplifier
||Phono MC: 130 microvolt/100ohm, 330ohm
Phono High Gain MC: 2.5mV/100 ohm
Phono man month: 2.5mV / 47kohm,
Tuner, AUX, Tape Play:150mV /, 47kohm
|An Output voltage/impedance
||Tape Rec: 150mV / 2.2kohm
Output: 1.5V, a maximum
|Phono maximum permissible input (THD 0.05%)
|man month, High MC :
|THD (THD, 20Hz - 20kHz)
|MC: 0.01% or less
man month: 0.003% or
Tuner, AUX, Tape: 0.003% or less
|Cross modulation distortion (SMPTE
||0.003% or less (at the time of an Output
|SN ratio (IHF-A network input shunt)
Tuner, AUX, Tape:
|Tone control (Volume-20dB)
||Bass: 70Hz, ±8dB
Treble: 20kHz, ±8dB
||High Cut: 7kHz, 6dB / oct
15Hz/20 Hz, 6dB / oct
|Transient killer operating time
|The semiconductor used
||Transistor: 47 pieces
FET: Six pieces
IC: Four pieces
Diode: 37 pieces
||A total of a maximum of 1000W
Power-switch interlock: Two lines
Power-switch un-interlocking.: One
||20W (Electrical Appliance and Material
|The maximum Dimensions
||Width 450x height 99x depth of 407mm