Accuphase proudly launches all-new A-250 for the firsttime in 5 years. With dignity, A-250 is fully redesigned of
A-200 which was introduced in 2012, and opening a newchapter as the newest flagship class-A monophonicpower amplifier.
A-250 is superior to A-200 electrical performance andsound quality which were thought as the limits.
A-250’s technical highlights are “Ultra low noise” and“Super high Damping Factor”.
The noise characteristic is especially admirable.
We believe A-250 shows the best performance ever inthe history of Accuphase Power Amplifiers.

1The size and weight of A-250 are the same as A-200.

2

The digital power meter shows the output power without
any effects of speaker impedance.
The 40-point LED bar graph shows the output voltage
level.
Two pairs of large speaker terminals are equipped.
They are useful for bi-wiring connection with loudspeakers.

3

To make the LED bar graph for output voltage level easy
to see, each element in the bar graph meter is enlarged
and thickened.
“Auto-range function” is newly provided with the range
selection of digital power meter.
Decimal point of the displayed value is automaticallyshifted in “Auto-range function” mode.

4

Strong power supply with a massive high-efficiency
Toroidal transformer and two large 100000μF filtering
capacitors are installed.

5The continuous average output power(rated outputpower) is 100W into 8Ω load.
However, its actual maximum output power is bigger,
saying191W into 8Ω and 1kW into 1Ω load.
**Output power is the same as A-200.

6

The performance highlights of A-250 are the “Ultra lownoise” and “Super high Damping Factor”.
The A-250 is consisted of a complete balanced input
amplifier block and a power amplifier block.
The balance input amplifier block is related to the noise
performance and the power amplifier block is related to
the Damping Factor.

7

The former model A-200 has the excellent noise
performance, however, A-250 achieves even 20% lower
output noise voltage than A-200.
A-250 is the lowest noise power amplifier in the existing
formidable Accuphase lineups.
A-250 guarantees,
SN ratio: 127dB @Maximum-gain

8

Output noise is reduced by some technologies.
Two amplifiers, they are consisted of complete balanced
input amplifier parts, are operated in parallel.
Output noise is ideally decreased to 70%.
The discrete configuration amplifier which has no ICs isalso effective for low noise.
The Balanced Input amplifier is placed as close to the
input terminal as possible and it succeeds in minimum
external noises.

9A-250 has the guaranteed 1,000 of Damping Factor.
It is the same as A-200, but the actual value is in excessof 1400.
It is 27% higher than A-200.
‘Damping Factor:
A index of speaker driving ability. Higher Damping Factor
amplifier has higher speaker driving ability.
DF = 8Ω / Output-impedance

10Output impedance is cut in half by the multiple connected
power amplifiers with 10-parallel push-pull arrangementof power MOS-FETs.

11

Remote Sensing is the technique to lower the output
impedance of amplifier by the negative feedback withsignal sensing from nearby the speaker terminals.
Balanced Remote Sensing is the technique to make theoutput impedance even lower by both the signal sensing
and the GND sensing, that is the negative feedback ofGND level.
Not only Damping-factor, but also Total Harmonic
Distortion and Intermodulation Distortion are all improvedby the Balanced Remote Sensing.

12Mechanical relays are the common components forspeaker protection but the super high Damping Factor isachieved by the lower impedance component, MOS-FETswitch.
Thanks to this MOS-FET switch, the Damping Factor,reliability and sound quality are all improved.
A-250 employs carefully-selected very low impedancecomponents like Large speaker terminals, Gold-plated
bus bars, a heavy-gauge edgewise coil and so on.
Making signal paths thick and short also helps attaining
the low impedance.

13