1 Pair of Audio Research Reference 600 Mono Power Amplifiers for sale
Silver Finish
In their original packaging
FACTORY REFURBISHED BY AUDIO RESERACH IN FEBRUARY 2025 - NEW TUBES!
LOCAL PICKUP ONLY
 
-----
FROM THE MANUFACTURER:
"Using all vacuum-tube input and driver stage circuitry in conjunction with 16 type 6550C output tubes, each amplifier puts out up to 600 watts of wide-bandwidth (12 Hz to 80 kHz) power into speaker impedances of one to 16 ohms. Measured frequency response (-3 dB points) is 2 Hz to 200 kHz. Main power supply energy storage is rated at 669 joules. Output terminals are proprietary gold-plated 5-way binding posts. Each output tube is individually biasable from the front panel. Illuminated meters provide A. C. monitoring, real-time power output and tube biasing data. Variable control of meter illumination and internal cooling-fan speed is standard. A standby mode limits tube current draw during warmup or between periods of operation. Front panels of both Reference Series models are available in anodized natural aluminum or black at no extra cost."
 
Power output
500 watts continuous at 16 ohms from 20Hz to 20kHz with less than 1% total harmonic distortion (typically less than .05% at 1 watt). Actual maximum power available (at the point of clipping) is dependent upon the following: 1) power line voltage. 2) power line condition (ie: regulation, distortion). 3) type and brand of power output tube used. Typical power under average circumstances will be around 550 watts. Maximum power under ideal conditions will be around 600 watts.
 
Power bandwidth
(-3dB points) 12Hz to 80kHz
 
Frequency response
(-3dB points at 1 watt) 2Hz to 200 kHz
 
Input sensitivity
2.0V RMS balanced for rated output
 
Input impedance
200K ohms balanced
 
Output taps
-
 
Output regulation
Approximately 0.5dB 16 ohm load to open circuit
 
Overall negative feedback
12dB
 
Damping factor
Approximately 16
 
Distortion
-
 
Slew rate
-
 
Rise time
-
 
Hum & noise
-
 
Power supply energy storage
-
 
Power requirements
105–125VAC 60Hz (210–250VAC 50Hz) 1600 watts at rated output, 2200 watts maximum, 800 watts at idle, 300 watts standby
 
Tube complement
REFERENCE 600: (8 matched pairs) 6550C power output, (4) 6550C regulators, (2) 7233 regulators, (2) 6922 regulator amplifier, (8)12AX7 driver, (2) 6922 input. The
 
REFERENCE 600 has sufficient bias adjustment range to allow the use of any of the following output tube types: 6550, 6550B, 6550C, KT88, KT90, KT91, KT100. The
 
REFERENCE 600 as supplied from Audio Research is equipped with Russian 6550C, which is our current choice for reliability and long service.
 
REFERENCE 600 MK II: (8 matched pairs) 6550C power output, (4) 6550C regulators, (3) 6922 regulators, (8) 6922 driver, (2) 6922 input.
 
REFERENCE 600 MKIII: (8 matched pairs) 6550C power output, (4) 6550C regulators, (3) 6N1P input/follower, (8) 6H30 driver
 
Dimensions
19" (48.3 cm) W x 10½" (26.7 cm) H x 29½" (74.9 cm) D. Handles extend 1½" (3.8 cm) forward
 
Weight
170 lbs. (77.2 kg) Net; Shipped in pairs, 495 lbs. (225 kg) per pair