|\260,000 yen(September, 1977 release)
Stereo power amplifier which constituted all the magnification stages from a
symmetrical type push pull, and also realized the physical characteristic of the
measurement limit by the formation of direct-current unit amplifier, adoption of
a careful selection part, and an audition test.
Based on the active
device which was excellent in the high frequency characteristic, all the
magnification stages consist of symmetrical type push pulls.
The standup characteristic, linearity, and stability excellent in a little
NFB could be realized by this, and while preventing generating of TIM,
low distorted-ization is realized.
In order to realize sound quality with few colorations, the
condenser in a NFB loop is removed and it has direct-current amplifier
Moreover, long-term operational stability is realized by
stabilizing a power source much more, in order to suppress direct-current drift, adopting a dual transistor as an input, and stabilizing center voltage, and also
attaining equalization of the temperature change of an active device.
The heavy weight class large-sized power transformer and the mass filter
capacitor of 40,000 micro Fx2 are carried in the power-source part.
Moreover, the parts currently used for the circuit have adopted what was
selected carefully based on the examination about sound quality change, a
durability test, etc.
When the speaker protection circuit is carried and
abnormalities occur to the short circuit, and amplifier/speaker of a speaker
cord, a speaker protection circuit catches abnormalities and intercepts between
P-300S and a speaker by relay.
Moreover, measures are taken so that the
shock noise generated when the power source of amplifier is turned on and off
using this circuit may not be generated, either.
In order to cut the
low-pass noise by the curvature and eccentricity of a record, the Subsonic
Filter which cuts 17Hz or less by 18 dB/oct is carried.
- Carry the
right-and-left independent type Attenuator which can be adjusted at a 1dB step
The output Direct-reading type large-sized power meter is
carried, and the number of watt at the time of 0dB and 8-ohm load can be read
for an output.
Moreover, a range changeover switch of -10dB-20dB is prepared
so that it can use also in the time of small volume.
For a reason when you would like to restrict the power more than needed,
the power limiter switch is carried. Full power, 1/2, and 1/4 can be chosen.
There was a wood case of natural tree
walnut finishing as an option.
||Stereo power amplifier
(Bothchannel drive, 20Hz - 20kHz, 0.03% or less of distortion)
|200 W/ch (4ohms)
150 W/ch (8ohms)
|THD (20Hz - 20kHz)
||0.03% or less (at the time of an Output
0.01% or less (at the time of a -3dB output)
0.05% or less (at
the time of a 50mW output)
||0.01% or less (at the time of an Output
||20Hz-20kHz+0 -0.2dB (at the time of an
1Hz-250kHz+0 -3dB (at the time of 1W output)
|Dumping factor (8-ohm load, 40Hz)
|A rated input / input impedance
|S/N ratio (input short-circuit, IHF-A curve)
||115dB or more (at the time of an Output
||Low Output-load-impedance type
||17Hz, 18 dB/oct
||Full power, 1/2, 1/4, a switch change
|The semiconductor used
||Transistor: 97 pieces
FET: Two pieces
IC: One piece
Diode: 92 pieces
|Power supply voltage
||At the time of no inputting: 100W
time of an 8ohm load Output power: 510W
||the width 445x height 160(piece -- it
includeds) x depth of 355mm
||Wood case A-2 (15,000yen)