|350,000 yen(July, 1987 release)
The Integrated Amplifier which constituted all to a drive stage from cascode
connection excellent in the high frequency characteristic on the basis of all
the magnification stage push pull drives.
It continues from the founder
P-300, the model change is undergone with P-300S, P-300X, P-300L, and P-300V, and it hits the 5th generation, and also super-low impedance drive which also
bears 1-ohm load, and realization of the more perfect balance input circuit are aimed at.
the broadband transistor whose collector loss Pc of an output
stage is 130W -- 10 -- it is parallel and constitutes from a total of 20 pieces.
Thereby, if total Pc makes 70% power efficiency of per [ 2600W ] channel and
an output stage, the theoretical marginal output amounts to 3700W, and has the
structure where linear and good electric power is sendable also into a low load
impedance by this.
20 transistors -- 10 -- it can be parallel, since it
constituted, the large current at the time of low impedance load can also be
coped with, and the low impedance of 1 ohm can also be driven.
connection is possible.
the same magnitude as amplifier with the same bridge
connection -- a phase -- reverse (negative phase) -- it is the method of
obtaining the double output in the 4-ohm load at the time of a stereo drive, by
putting in a signal and connecting a speaker to the output end of both
Usually, although a phase inversion circuit is inserted in one amplifier, the polarity of the difference input circuit of two amplifier is
used, at the time of bridge connection, it is the method of making a connection
change so that a negative phase signal may be inputted mutually, and it
constitutes the pure change circuit from P-300V.
The full-scale 40kohm
balance input is carried. It is possible to connect the balance output of all
impedance with 3 P-XLR type connector of an international standard.
balance input circuit of P-300V has the composition of pouring in a signal as it
is, to plus of a difference input circuit, and a minus input, and has ideal
Moreover, in the case of this system, a level control must be
inserted in plus and each minus input, but the 1dB step Attenuator with few
interlocking errors is adopted.
In order to suppress the switching distortion at the time of the Koide power produced in an output stage, the operating point is strictly set up so that the element of each PNP/NPN may not be cut off with an incoming signal. Moreover, the preceding paragraph which drives a final stage consists of cascode push pulls equivalent to a non switching Class-A drive by MOS FET. And the preceding paragraph is also considered as Class-A cascode push pull composition.
This has realized few stable output stages distorted from the Koide power of a noise domain to the Oide power of an Output power.
The input circuit constitutes the
cascode bootstrap push pull circuit.
A cascode bootstrap circuit is further excellent in the frequency response and the phase characteristic of a super-high region with high gain, and is the circuit with which it was satisfied of the conditions with which the input stage that there is no aggravation of a distortion also to change of input impedance should be equipped.
constituting this circuit from a push pull -- a broadband drive
stage -- conjointly -- the base in NF loop -- the characteristic is improved.
A power-source part prepares the winding only for a preceding paragraph
magnification circuit in a transformer, rectifies right-and-left independence, and supplies it through a filter circuit.
The incoming signal has
adopted the direct connection system direct inputted into Input.
reason, it is while omitting a direct current with direct-current servo system
used as Accuphase original since there is a possibility of it being amplified, appearing in an output and damaging a speaker when the large preamplifier of
direct-current drift etc. is connected,direct-current drift of the amplifier by
a temperature change itself is also stabilized.
The output meter
convenient to monitor is carried.
The Direct reading of the output electric
power at the time of 8-ohm load can be carried out with dB in logarithm
compression type peak power meter.
Three inputs of one balance and two
unbalance are carried, and it can change with the switch of the front panel.
One line in an imbalanced input is prepared in the sub panel of the entire
Connection of A and B-2 system is possible for a speaker.
Since the speaker of those who are not using it may resonate in response to
vibration and may spoil sound quality, it considers so that the speaker which is
not operating may be short-circuited automatically and resonance may be
The surface panel upper part serves as gold tone scratch hair
line finishing, and the lower sub panel serves as black hair line finishing.
Moreover, the sideboard of the natural persimmon is attached to both sides.
||Stereo power amplifier
(20Hz - 20kHz, 0.01% of
|At the time of stereo specification (both
channel simultaneous operation)
2ohm load: 350 W/ch
4ohm load: 280 W/ch
8ohm load: 180 W/ch
16ohm load: 90 W/ch
At the time of monophonic
specification (bridge connection)
4ohm load: 700W
8ohm load: 560W
16ohm load: 360W
||At the time of stereo specification: 0.01%
(both channel simultaneous operation, 2ohms - 16-ohm load)
At the time of monophonic specification: 0.01%
(bridge connection, 4ohms - 16-ohm load)
||20Hz-20kHz+0 -0.2 dB
(at the time of a continuation average output level control MAX)
||28.0dB (at the time of stereo monophonic
||At the time of stereo specification: 2ohms -
At the time of monophonic specification (bridge connection): 4ohms -
||At the time of stereo specification: 300
At the time of monophonic specification (bridge connection): 150
|Input sensitivity (8-ohm load)
||At the time of stereo specification
the time of a continuation average output: 1.5V
At the time of 1W output:
At the time of monophonic specification (bridge connection)
time of a continuation average output: 2.7V
At the time of 1W output: 0.12V
(the time of A compensation and
|120dB (at the time of input short-circuit
and a continuation average output)
100dB (at the time of input 1kohm and
||Conformity impedance: 4ohms - 100ohms
|Power output meter
||Logarithm compression type
- 40dB -
+3dB, and an output Direct-reading scale
|A use transistor, a diode
||Transistor: 90 pieces
FEt: 16 pieces
IC: Eight pieces
Diode: 73 pieces
||At the time of no inputting: 130W
Electrical Appliance and Material Control Law: 630W
At the time of an
8ohm load Output power: 600W
||the width 475x height 170(piece -- it
includeds) x depth of 408mm