Accuphase A-45

It is a pure A class stereo power amplifier developed by following the design technology as an amplifier located between A-60 and A-30.

The whole amplifier is constructed using the latest Instrumentation Amplifier method.
In this system, the signal path from the input terminal to the power amplifier stage is fully balanced, and not only is it excellent in various characteristics such as CMRR (Common Mode Rejection Ratio) and distortion factor, but it is also resistant to environmental changes such as external noise, and stability and reliability as a power amplifier are improved.

The amplifier is equipped with an MCS + circuit and a current feedback amplifier circuit to further improve electrical performance.
MCS (Multiple Circuit Summing-up) is a circuit method to improve various characteristics by connecting the same circuit in parallel. MCS + circuit is a further evolution of this circuit and realizes further noise reduction by extending the parallel operation part to A-class drive stage of current-voltage conversion part.
The current feedback amplifier circuit feeds back the output signal in the form of a current. Since the impedance of the feedback input part is extremely low, phase rotation hardly occurs, and various characteristics can be greatly improved with a small amount of NFB.
A power MOS-FET, which has a reputation for sound quality and reliability, is used as the output device. Each channel is driven by 6 parallel push-pull operation. The MOS-FET has negative thermal response to temperature rise, so that thermally stable operation can be obtained. This is a pure A-class system that brings out the charm of music.

A large-size high-efficiency toroidal transformer of up to 600 VA is adopted for the power supply section, and a large-capacity capacitor of 47,000 uFx2 is used for the smoothing capacitor.

Equipped with 4-stage gain control.
In this function, the gain is switched by the first stage amplifier of the instrumentation amplifier system, and residual noise is reduced.

A fully balanced input circuit is adopted, making it less susceptible to extraneous induction noise.

Main components of printed board copper foil and signal path are made into gold plates.

Equipped with an analog type large power meter.
Meter OFF function and sensitivity switching are also available.

The speaker terminal uses a large terminal that can be used with a Y lug or banana plug.

The A-45 is bridge-connected and can be used as a high-power monaural power amplifier.
Use the mode selector switch to switch between dual mono / stereo / bridge connections.

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Power output: 45 watts per channel into 8 ohm (stereo), 180 watts into 8 ohm (mono)
Frequency response: 20Hz to 20kHz
Total harmonic distortion: 0.03%
Damping factor: 200
Gain: 28 dB
Input sensitivity: 0.76V
Signal to noise ratio: 115dB
Speaker load impedance: 2 to 16 ohm
Dimensions: 465 x 211 x 464mm
Weight: 30.9kg