Audio Database

The

Accuphase P-250
175,000 yen(September, 1974 release)

Description

Stereo power amplifier which is planned not to pursue powerful power but to say that it catches up to a limit about sound quality, and was developed.
The part selected carefully is used and sound quality and durability are fully examined.

100 W/ch (8ohms) is realized by the parallel push pull drive which used the large-sized power transistor for the output stage.
Moreover, the distortion at the time of the Koide power is removed to the limit by examining the bias current of each stage thoroughly.

Sufficient energy for a speaker is sent, and in order to follow in footsteps of the signal which changes a lot violently, the large-sized power transformer and the condenser of 20000 micro Fx2 are carried in the power-source part.

The system which changes the dumping factor of amplifier is adopted so that the speaker designed by the Tube amplifier age may also be matched.
It can be possible to choose three, 20 (NORMAL) or more, and 5 (MEDIUM) and 1 (SOFT), in the time of 8-ohm load, and, thereby, sound quality peculiar to tube amplifier can also be enjoyed now.

When a cord short-circuits henceforth [ output terminal ] or abnormalities occur inside amplifier, the protection circuit intercepted by relay from the moment is carried. This circuit will return to the original state automatically, if abnormalities are repaired.
Moreover, the impedance detector circuit is carried, and when a speaker terminal or later short-circuits before Switch ON, a relay enters.

A large-sized power meter can be carried and balance on either side and Output voltage can be checked. Moreover, a 0dB -10dB-20dB range is changed with a push switch so that it can use also in the time of small volume.
100W is set up as 0dB by 8-ohm addition.

the unnecessary input which takes place by the run bull of a phone motor, or super-low-pass arm resonance -- a crown -- in order to prevent modulating sound, and losing dignity, or mixing with the signal of treble by the unnecessary input of super-upper register, and a beat occurring,The band pass filter which removes 17Hz or less 24kHz or more by 18 dB/oct is built in.
An ON-OFF change is possible for this filter in the front.


At
The

Rating of a mode
System Stereo power amplifier
Output power (both channel drive)
20Hz - 20kHz, 0.1% of a distortion
4ohm load: 140 W/ch
8ohm load: 100 W/ch
16ohm load: 50 W/ch
Higher-harmonic-wave distortion (20Hz - 20kHz) At the time of an Output power: 0.1%
- At the time of a 3dB output : 0.05%
At the time of a 50mW output: 0.1%
IM distortion (arbitrary frequency of 20Hz - 20kHz) At the time of an Output power: 0.1%
Frequency response (at the time of an Output power) 20Hz-20000Hz+0 -0.2 dB
Dumping factor
(For 8-ohm load and 20Hz - 20kHz)
NORMAL:20
MEDIUM:5
SOFT:1
A rated input / input impedance 1.0V/100kohm
S/N ratio (at the time of an Output power) 94dB
Stereo headphone Conformity impedance: 4-32ohms
Audio band pass filter 17Hz or less, 20kHzor more:18 dB/oct
Power meter level
Range change 0dB: 0dB=100W (8ohms)
Range change -10dB: 0dB=10W (8ohms)
Range change -20dB: 0dB=1W (8ohms)
A use transistor, a diode 36Tr, 34Di
Power source 100, 117, 220, 240V / 50-60Hz
Power consumption At the time of no inputting: 70W
At the time of the maximum except take-off (8ohm load): 375W
Dimensions Width 445x height 152x depth of 355mm
Weight 19.5kg