
Accuphase P-370 |
|
360,000 yen(March, 2001 release) |
Stereo power amplifier which inherited the design technology cultivated so far
and applied the polish to sound quality further by maturing of technology and
sensitivity.
It excelled in many characteristics, such as a frequency
response, a current gain linearity, and switching, and the high power transistor
of the collector loss 150W and collector current 15A is adopted as an output
element. This transistor was constituted from a 3 parallel push pull, and
effective heat dissipation processing is realized by attaching on a large-sized
heat sink.
This has realized Oide power even with linear super-low impedance
load.
The current feedback (current feedback type) magnification circuit
which returns an output signal in the form of current is adopted.
The
principle of this circuit lowers the impedance of the input terminal by the side
of a return first, detects current, carries out I-V (current-voltage) conversion
of that current with a transformer impedance amplifier, and makes an output
signal.
Since the impedance of the return input portion is very low, it was
hard to generate phase rotation and, as a result, the necessity for a phase
guarantee of it has almost been lost. For this reason, since the characteristic
is sharply improvable by a little NFB(s), the natural energy response excellent
in dynamic characteristics, such as a standup, has been realized.
In the power-source part, the large power-capacity Troy Dahl type of about
700 VA is adopted as a power transformer. Furthermore, the high load material
of the A vibrationproofing effect was used for heat conduction, it adhered
to the case, and the influence on the exterior is prevented.
The Troy Dahl type
transformer has the features, like impedance is very low, it is small, and
conversion efficiency is high in order to coil thick copper wire around a
doughnut-like core. In P-370, the super ring type was adopted, the section of
the iron core was close to the circle, the coil could also be rolled closely
circularly, and since adhesion nature is good, the outstanding characteristic
has been acquired.
Moreover, two 47,000-micro F mass capacitors are carried
in the aluminum electrolytic capacitor.
The input terminal strong
against external guidance noise for balance connection is carried.
It
can be used also as monophonic power amplifier by bridge connection.
Bridge
connection inputs a negative phase signal into two amplifier with which polarity
differs, is the method of connecting a speaker to the output end of both
amplifier, and can supply richer power.
The mode changeover switch by the side of a rear panel performs a change.
By a dual mono-position, it is possible to use the output for center Woofers,
or to output channel signal of one of the two from both the speaker terminal,
and to use it for a by amplifier drive.
The analog
type large-sized power meter is carried.
The switch which turns on and off
operation and lighting of meter is also carried.
Two speaker terminals
which can respond also to a thick speaker cable are carried.
Usually, although it is used changing, it is also possible to operate A/B both systems and to make bi-wiring connection.
|
Form |
Stereo power amplifier |
Rated continuation average output
(20Hz
- 20kHz) |
At the time of stereo specification :
|
400 W/ch (it restricts to 1 ohm and a music
signal)
300 W/ch (2ohms)
150 W/ch (4ohms)
75 W/ch (8ohms)
|
At the time of monophonic specification :
(Bridge connection) |
800W (it restricts to 2 ohms and a music
signal)
600W (4ohms)
300W (8ohms)
|
|
THD |
At the time of stereo specification :
|
0.05% (2-ohm load)
0.02% (4ohms - 16-ohm
load) |
At the time of monophonic specification :
|
0.02% (4ohms - 16-ohm load)
|
|
IM distortion |
0.003% |
Frequency response |
20Hz-20kHz+0 -0.2 dB (at the time of a rated
continuation average output)
0.5Hz-160kHz+0 -3.0dB (at the time of 1W
output) |
Gain |
28.0dB (at the time of a stereo / monophonic
specification) |
Load impedance |
At the time of stereo specification: 2ohms -
16ohms
At the time of monophonic specification (bridge connection): 4ohms -
16ohms
* Restrict to a music signal and Stereo 1 ohm and monophonic 2ohm
load are possible. |
Dumping factor |
200 (at the time of a stereo / monophonic
specification) |
Input sensitivity (at the time of 8-ohm
load) |
At the time of stereo specification :
|
0.98V (at the time of a rated continuation
average output)
0.11V (at the time of 1W output)
|
At the time of monophonic specification :
(Bridge connection) |
1.95V (at the time of a rated continuation
average output)
0.11V (at the time of 1W output)
|
|
Input impedance |
Imbalanced Input: 20kohm
Balance
input: 40kohm |
S/N
(A compensation, input short-circuit) |
120dB (at the time of a rated continuation
average output) |
Power output meter |
A logarithm compression type, with a display
putting-out-lights function
- 50dB - +3dB |
Power source |
AC100V, 50Hz/60Hz |
Power consumption |
44W (at the time of no inputting)
475W
(Electrical Appliance and Material Control Law)
335W (at the time of an
8-ohm load Output power) |
The maximum Dimensions |
Width 475x height 180x depth of 417mm
|
Weight |
24.4kg |
Attachment |
AC power cord |
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