|
| Accuphase P-266 |
|
| 220,000 yen(March, 1983 release) |
Stereo power amplifier which was born with the development technology of the
Accuphase which has cultivated for years and which uses MOS FET.
Four kinds
of use, stereo power amplifier, Class-A stereo power amplifier, monophonic power
amplifier, and Class-A monophonic power amplifier, is possible.
Power
MOS FET (Metal-Oxide Semiconductor Field Effect Transistor)Since there is no
electric charge accumulation like a bipolar transistor, it excels in the
high-speed switching characteristic, and notching distortion is not generated in
a high region, but the distorted characteristic which was excellent over the
large zone can be acquired.
Also, a voltage-controlled device to the input signal
voltage applied to the gate only to the power amplifier, and you can do great
demand signal bipolar transistor power compared to the early stage of the drive
stage is small enough power for the device and , you can choose a good
device.
furthermore, a high gain -- since an element, the
number of magnification stages can be lessened, and stability can be raised by
the simplification of a signal course.
And the region's large current to the negative temperature coefficient
is some element of the current is caused by abnormal increase pellet temperature
is soaring and the negative temperature coefficient for the current direction
of working to reduce the temperature will drop to The element of self-defense
to prevent the destruction of property.
Moreover, it also has the features, such
as having the outstanding high region characteristic and linearity.
It consists of a powerful output stage and a power-source
part, an output stage is constituted from a triple push pull of MOS FET, and a
margin called PD(drain maximum loss electric power) 600W is given so that low
impedance load can also fully be borne.
It is possible to make it
operate also by the full-scale pure Class-A system in which the changeover
switch of operation is carried and which the domain of a push pull element of
operation overlaps completely.
A change in Class-A operation is performed in
a bias electronic switch. Normal operation and Class-A operation are changed by
incorporating an optocoupler in a circuit, blinking a light emitting diode, and
changing bias current.
The bridge drive switch is carried and it can be
used also as Oide power power amplifier.
By the principle's of operation
inputting the signal of negative phase into each amplifier by the same ripple, and connecting a speaker to the output of both amplifier, the voltage impressed
to a speaker becomes twice and can take out 4 times when operating one set of
amplifier theoretically as many outputs.
By this system, there is also a
merit that eventh higher-harmonic-wave distortion is canceled for a negative
phase drive, and the characteristic is improved. Moreover, since the energy
which flows from a power source flows alternately with plus and minus and the
energy of only one way does not flow into both amplifier, it is possible to mean
that the rate of power source variation on appearance was improved, and to send
out energy with a good linearity to a speaker.
The cascode connection
push pull composition adopted as P-300X or M-100 grade is adopted as a predrive
stage.
A cascode is a circuit used for high frequency like the front end of
a tuner, it does not generate a Miller effect but the high region characteristic
is excellent. furthermore, the base before a linearity is good to the full
limits of an element and applying NFB -- the characteristic is improved sharply.
The FET input is adopted, an input coupling capacitor is removed, and it
is made direct connection.
The way things stand, if it amplifies to a direct
current and uses together with the preamplifier of direct-current leak, a direct
current is amplified and a speaker may be damaged. In order to prevent this,
while having given the direct-current return with direct-current servo amplifier
and intercepting a direct current, by P-266, direct-current drift generated in a
circuit is stabilized.
In order to strengthen the power source of a
preamplifier part, the rectifier circuit of the right-and-left channel was made
to become independent, and is prepared in each print circuit board.
Furthermore, it strengthened with the power regulator and low
impedance-ization is realized over a broadband.
The Subsonic Filter is
carried in order to remove a super-low-pass noise.
- Carry the
Attenuator which changes at a 1dB step to 20dB.
The logarithm
compression type peak level meter carrying a hold switch is carried, the Direct
reading of the output electric power of dB value and 8-ohm addition can be
carried out, and a peak hold is also possible by changing.
A peak value in
the meantime is held with the sampling period in every 3 seconds at the time of
a peak hold.
The speaker change mechanism by output relay is carried.
There is a cabinet of natural rosewood finishing as an option.
|
| Form |
Stereo power amplifier |
Continuation average output
(20Hz -
20kHz, 0.01% of distortion) |
| At the time of stereo specification
|
| Normal: |
200 W/ch (4ohms)
130 W/ch (8ohms)
65
W/ch (16ohms) |
| Class-A: |
55 W/ch (4ohms)
30 W/ch (8ohms)
18
W/ch (16ohms) |
|
| At the time of monophonic specification
(bridge connection) |
| Normal: |
400W (8ohms)
180W (16ohms)
|
| Class-A: |
110W (8ohms)
55W (16ohms)
|
|
|
THD
(20Hz - 20kHz, 0.25W
- continuation average output) |
| At the time of stereo specification :
|
0.01% (4-ohm load)
0.005% (8ohms -
16-ohm load) |
| At the time of monophonic specification
(bridge connection) : |
0.01% (8-ohm load)
0.005% (16-ohm load)
|
|
| IM distortion (IHF) |
0.003% |
| Frequency response |
20Hz-20kHz+0 -0.2 dB (at the time of a
continuation average output level control MAX)
0.5Hz-300kHz+0 -3 dB (at the
time of 1W output level control MAX)
0.5Hz-150kHz+0 -3 dB (at the time of 1W
output level-control 6dB) |
| Gain |
At the time of stereo specification: 27.8dB
At the time of monophonic specification: 33.7dB |
| Load impedance |
At the time of stereo specification: 2ohms -
16ohms
At the time of monophonic specification: 4ohms - 16ohms
|
| Dumping factor |
At the time of stereo specification: 120
At the time of monophonic specification: 60 |
Input sensitivity/impedance
(at the time of 8-ohm load) |
| At the time of stereo specification :
|
1.3V/20kohm (at the time of a continuation
average output)
0.12V/20kohm (at the time of 1W output IHF)
|
| At the time of monophonic specification :
|
1.1V/20kohm (at the time of a continuation
average output)
0.06V/20kohm (at the time of 1W output IHF)
|
|
| S/N (A compensation) |
| At the time of stereo specification :
|
120dB (at the time of input short-circuit
and a continuation average output)
100dB (at input 1kohm, the time of 1W
output IHF) |
| At the time of monophonic specification :
|
110dB (at the time of input short-circuit
and a continuation average output)
90dB (at input 1kohm, the time of 1W
output IHF) |
|
| Stereo headphone |
Low Output-load-impedance type
|
| Subsonic Filter |
17Hz, -12 dB/oct |
| Power output meter |
A logarithm compression peak directions
type, -40dB-+3dB, and an output Direct-reading scale
With a peak hold change
|
| The semiconductor used |
Transistor: 34 pieces
FET: 18 pieces
IC: Seven pieces
Diode: 68 pieces
Optocoupler: Two pieces
|
| Power supply voltage |
AC100V/117V/220V/240V, 50Hz/60Hz
|
| Power consumption |
| Normal: |
120W (at the time of no inputting)
500W
(at the time of an 8-ohm load Output power) |
| Class-A: |
150W (at the time of no inputting)
190W
(at the time of an 8-ohm load Output power)
|
|
| Dimensions |
the width 445x height 160(piece -- it
includeds) x depth of 373mm
Wood cabinet: Width 466x height 190x depth of
385mm |
| Weight |
20kg |
| Option |
Wood cabinet A-8 (16,000yen) |
|
|
|
.JPG)
.JPG)
.JPG)
.JPG)