Power Amplifier (Class-A, 2x45w).
The Accuphase A-47 uses latest instrumentation amplifier topology throughout, which allows fully balanced transmission in all signal handling stages. The power amplifier section features further improved MCS+ topology and the renowned current feedback approach. This results in electrical characteristics that surpass even the demanding standards set by its predecessors. Employing only highest grade materials and strictly selected parts, the A-47 realises very low output impedance which ensures that constant drive voltage is available for the speakers.
The output stage features power MOS-FETs renowned for their excellent sound and superior reliability. For each channel, six of these devices are arranged in a parallel push-pull class A arrangement. MOS-FETs have excellent frequency response characteristics and high input impedance, which reduces the load of the preceding (drive)stage. Driving these devices in pure class A means that constant power is always supplied, regardless of the presence or absence of a musical signal.
This makes the amplifier completely immune to external influences and ensures stable operation at all times.
Click here for PDF brochure.
- Pure Class A operation delivers quality power: 45 watts x 2 into 8 ohms
- Power MOSFET output stage features 3-parallel push-pull configuration
- Instrumentation amplifier principle
- Further improved MCS+ circuit topology
- Current feedback principle combines stable operation with outstanding sound quality
- Bridged mode allows upgrading to true monophonic amplifier
- Large high-efficiency toroidal transformer
- 4-stage gain control
- Continuous Average Output Power (20–20,000 Hz): Stereo operation (both channels driven) - 360 watts per channel into 1 ohm, 180 watts per channel into 2 ohms, 90 watts per channel into 4 ohms, 45 watts per channel into 8 ohms. Monophonic operation (bridged connection) - 720 watts into 2 ohms, 360 watts into 4 ohms, 180 watts into 8 ohms.
- Total Harmonic Distortion: Stereo operation (both channels driven) - 0.05% with 2 ohm load, 0.03% with 4 to 16 ohm load. Monophonic operation (bridged connection) - 0.05% with 4 to 16 ohm load
- Intermodulation Distortion: 0.01%
- Frequency Response: At rated output: 20 – 20,000 Hz +0, -0.2 dB. At 1 watt output: 0.5 – 160,000 Hz +0, -3.0 dB
- Gain: 28.0 dB (with GAIN selector at MAX) (Stereo and monophonic operation)
- Gain Selection: MAX, -3 dB, -6 dB, -12 dB
- Output Load impedance: Stereo operation - 2 to 16 ohms. Monophonic operation: 4 to 16 ohms
- Damping Factor: 500
- Input Sensitivity (with 8-ohm load, GAIN selector in MAX position): Stereo operation - 0.76 V for rated continuous average output (30 W). 0.11 V for 1 watt output. Monophonic operation - 1.51 V for rated continuous average output (120 W). 0.11 V for 1 watt output
- Input Impedance: Balanced - 40 kilohms. Line - 20 kilohms
- Signal-to-Noise Ratio (A-weighted, input shorted): 115 dB (GAIN selector at MAX), 120 dB (GAIN selector at -12 dB) At rated continuous average output
- Output Level Meters: -60 dB to +3 dB (indication in dB and %) Logarithmic scale. Operation selector: OFF / NORMAL / HOLD (∞). Meter sensitivity selector (-20 dB). ＊Monophonic operation: same value displayed for left/right.
- Power Requirements: AC 120 V/230 V, 50/60 Hz (Voltage as indicated on rear panel)
- Power Consumption: 200 watts idle. 410 watts in accordance with IEC 60065
- Maximum Dimensions: Width 465 mm, Height 211 mm, Depth 464 mm
- Mass: 31.9 kg net, 39.0 kg in shipping carton