Audio Database
P-250
Commentary

This is a stereo power amplifier developed with the policy of pursuing sound quality to the limit instead of pursuing powerful power.
Carefully selected parts are used, and sound quality and durability are well considered.

100W/ch (8 Ω) is achieved by parallel push-pull drive using a large power transistor at the output stage.
In addition, by thoroughly examining the bias current of each stage, the distortion at a small output is eliminated to the limit.

The power supply section is equipped with a large power transformer and a 20000 μ Fx2 capacitor in order to send sufficient energy to the speakers and to follow signals that change rapidly and greatly.

We have adopted a method of switching the damping factor of the amplifier so that it matches the speaker designed in the era of tube amplifier.
With an 8 Ω load, you can choose from three options : 20 or more (NORMAL), 5 (MEDIUM), and 1 (SOFT). This allows you to enjoy the unique sound quality of the tube type amplifier.

In the event of a short-circuit of the cord after the output terminal or an error inside the amplifier, a protective circuit is mounted which is cut off by a relay from the moment. This circuit automatically returns to its original state when the error is corrected.
In addition, an impedance detection circuit is mounted so that the relay does not come in when a short circuit occurs after the speaker terminal before the switch is turned on.

Equipped with a large power meter, you can check the left / right balance and output level. In addition, you can switch between 0 dB, -10dB and -20dB ranges with a push switch so that it can be used at low volume.
100W for 8 Ω load is scaled as 0 dB.

In order to prevent unwanted input caused by the rumble of the phono motor or the resonance of the arm in the ultra-low frequency range from modulating the middle and high frequency range to degrade the quality, or from unwanted input in the ultra-high frequency range from mixing with the high frequency range signal to generate a beat, it has a built-in band-pass filter that removes at 18dB/oct. frequencies below 17 Hz and above 24 kHz.
This filter can be switched between ON and OFF at the front.

Model Rating
Type Stereo power amplifier
Rated output (both channel drive
20 Hz to 20 kHz, Distortion Factor 0.1%)
4 Ω load : 140W/ch
8 Ω load : 100W/ch
16 Ω load : 50W/ch
Harmonic distortion (20 Hz to 20 kHz) Rated power : 0.1%
0.05% at -3dB output
50 mW output : 0.1 per cent
IM Distortion Factor (any frequency from 20 Hz to 20 kHz) Rated power : 0.1%
Frequency response (at rated output) 20 Hz ~ 20000 Hz + 0 -0.2 dB
Damping factor
(8 Ω load, between 20 Hz to 20 kHz)
NORMAL:20
MEDIUM:5
SOFT:1
Rated input / input impedance 1.0V/100k Ω
S/N ratio (at rated output) 94dB
Stereo headphone Applicable Impedance : 4 ~ 32 Ω
Audio bandpass filter 17 Hz or less, 20 kHz or more : 18dB/oct.
Power meter level
0dB: 0 dB = 100W (8 Ω)
-10dB: 0 dB = 10W (8 Ω)
-20dB: 0 dB = 1W (8 Ω)
Transistors and diodes used 36 tr, 34 di
Pwer 100, 117, 220, 240V/50 ~ 60 Hz
Power consumption No input : 70W
Maximum output (8 Ω load) : 375W
External dimensions Width 445x Height 152x Depth 355 mm
Weight 19.5kg
Sold Separately Wood Cabinet A-2