频率响应非常优异
ARC二当家,额定输出250瓦,但这还不是极限,真正遇到Clipping的底限可到270瓦,所以250瓦只算转速飙到红线区,270瓦才算催到底。频率响应呢?0.5Hz~110kHz,代表REF 250可以把高分辨率音乐的高频宽尽可能地发挥,甚至超过SACD规格的100kHz。想搬动这250瓦的真空管后级,最好不要一个人动手,重量33.2公斤
使用全平衡线路
以往ARC使用的功率管大多是6550,不过新一代的ARC后级大概都换上了KT120功率管,比6550效率更好,功率更大,输出级用上三对(6只)KT120,驱动级则是一对KT120,输入级和自家前级一样,使用一对6H30,整流管则是6550C。延续传统之处还有全平衡线路,ARC一直是全平衡的信奉者,REF 250不仅使用全平衡线路,输入端子还很有洁癖,只有一组平衡输入。
详细参数
POWER OUTPUT: 250 watts per channel continuous from 20Hz to 20kHz. 1kHz total harmonic distortion typically 0.5% at 250 watts, below .04% at 1 watt. Approximate actual power available at “clipping” 270 watts (1kHz). (Note that actual power output is dependent upon both line voltage and “condition” i.e.: if power line has high distortion, maximum power will be affected adversely, although from a listening standpoint this is not very critical.)
POWER BANDWIDTH: (-3dB points) 5Hz to 70kHz.
FREQUENCY RESPONSE: (-3dB points at 1 watt) 0.5Hz to 110 kHz.
INPUT SENSITIVITY: 2.4V RMS Balanced for rated output. (25.5 dB gain into 8 ohms.)
INPUT IMPEDANCE: 200K ohms Balanced.
OUTPUT TAPS: 4, 8, 16 ohms.
OUTPUT REGULATION: Approximately 0.9dB 16 ohm load to open circuit (Damping factor approximately 10).
OVERALL NEGATIVE FEEDBACK: 8.8dB.
SLEW RATE: 20 volts/microsecond.
RISE TIME: 1.5 microseconds.
HUM & NOISE: Less than 0.2mV RMS – 110dB below rated output (IHF-A weighted, input shorted, 16 ohm output).
POWER SUPPLY ENERGY STORAGE: Approximately 900 joules.
POWER REQUIREMENTS: 105-130VAC 60Hz (260-250VAC 50Hz) 770 watts at rated output, 1000 watts maximum, 380 watts at “idle,” 1 watt off.
TUBES REQUIRED: 3 Matched pair KT120 (Power output V1-6); 1 Matched pair KT120 (Driver V8-9); 2 6H30 (Gain stage V7 and Regulator Driver V10); 1 6550C (Regulator V11).
DIMENSIONS: 19" (48.3 cm) W x 8.75" (22.2 cm) H x 19.5" (49.5 cm) D. Handles extend 1.5" (3.8 cm) forward.
WEIGHT: 73 lbs. (33.2 kg) Net; 88 lbs. (40 kg) Shipping.