Audio Research Classic 150

Audio Research Classic 150 Mono Amplifiers pair -- excellent pair of "classic" Audio Research tube amplifiers.  140W each of triode tube amplification -- includes optional balanced input.  Series II update done.  All FET input stage, 8 6550 output tubes, transformer coupled.  These are from the original owner and purchased as FRU's -- Factory Refurbished.  Purchased early '90's.  All original manual and factory crates.  These were tested here in our store and played the Wilson Sasha DAW's wonderfully -- full and well rounded presentation.  
Specifications:
140 watts minimum continuous at 8 ohms from 10Hz to 20kHz with less than 0.8% total harmonic distortion (typically below .005% at 1 watt). Approximate actual power available at "clipping": 150 watts (1kHz).Power bandwidth(-3dB points): 7Hz-100kHzFrequency response Input sensitivity.6V RMS for rated outputInput impedance60K ohms, nominalOutput taps2, 4, 8 ohmsOutput regulationApproximatefully 0.3dB, 8 ohm load to open circuitOverall negative feedback20 dBDamping factorApproximately 30Distortion Slew rate25V/µsRise time2 µsHum & noiseLess than 2mV RMS 90dB below rated output (broad-bandwidth unweighted, inputs shorted)Power supply energy storageApproximately 350 joulesPower requirements105-125 VAC 60Hz (210-250 VAC 50Hz) 650 watts at rated output, 440 watts at "idle". 145 watts at "standby"Tube complement(4 matched pairs) 6550Other Dimensions19" W by 10.5" H by 16" D 
Condition is excellent considering the vintage of these amplifiers -- these amps are sure to please any tube afficianado!  Note that these were originally purchased as Audio Research factory refurbished and is noted on the original boxes.