Nikko Alpha 220 power-amp

Nikko Audio's Alpha 220 is a 120 watts per channel power amplifier having a DC servo-feedback loop, non-switching output circuitry, and a high slew rate The unit's input circuitr uses dual field effect transistors (FEDs) for lowest noise and distortion; the remaining stages employ wideband bipolar transistors. The amplifier has a slew rate of 100 volts per microsecond and a rise time of one microsecond. Low frequency signals are monitored and corrected by a DC servo-feedback loop.

The output stage is operated in a continuous non-switching mode, using circuitry that tracks transistor bias in synchonization with the music signal, to avoid excessive heat generation and resultant cost associated with traditional Class A designs while nonethless offering the exceptional degree of sonic clarity and openness of Class A operation. Additional features include; protection circuits to prevent speaker damage even if the preamp has a DC offest signal; front panel headphone jack and speaker selector switches; indicator lamps that monitor power-on and protection-circuit status.

Specifications:

Continuous Power Output per Channel:

More than 120 watts  - 20 -20,000 Hz at 8 Ω

More than 130 watts - 20 - 20,000 Hz at 4 Ω

More than 120 watts - 1000 Hz at 8 Ω

More than 130 watts - 1000 Hz at 4 Ω

Total Harmonic Distortion :

Continuous Power Output  at 8 Ω :   no more than 0,008%

Continuous Power Output  at 4 Ω :  no more than 0,02%

1 Watt power Output (8 ohms):  no more than 0,02%

Intermodulation Distortion :

Continuous Power Output  at 8 Ω :  no more than 0,01%

1 Watt Power Output :  no more than 0,02%

IHF Power Bandwidth (8 ohms):  5 - 70,000 Hz

Damping Factor at 1000 Hz (8 ohms):  more than 60

Frequency Response (Normal Input 8 Ω)

At 1 Watt Power Output :  10 - 100,000 Hz +0, -1 dB

Input Sensitivity for 120 watts Power Output

Main In :  1 V ±2 dB

Signal-to-Noise Ratio (IHF A network):

Main (Normal, Direct) :  better than 105 dB

Signal-to-Noise Ratio (DIN Filter):

Main IN (Normal, Direct) :  better than 90 dB

Channel Balance:  no more than 1 dB

Residual Hum and Noise, 8 Ω:  no more than 0,5 mV

Idling Current:  40 - 120 mA

Midpoint Voltage:  0 ±20 mV

Muting Delay Time:  3 - 7 seconds

Power Requirements:

W-type :  AC 120 V, 60 Hz

E-type :  AC 220 V, 50 Hz

B-type :  AC 240 V, 50 Hz

Power Consumption:  480 W (620 VA)

Dimensions (W x H x D):  482 x 138 x 344 mm (19" x 5-1/3" x 13-1/2")

Weight:  13,5 kg (29,7 lbs)