Audio Research M300 High Definition Power Amplifier Monoblock Pair

For sale is a pair of Audio Research M300 hybrid mono-blocks. These behemoths are 300 watts each and were often used in pro audio applications. They use solid state input stages and tube output stages. Cosmetically these amps are in very good condition. They have very few blemishes between the both of them. There are a few dents on the bottom edge of the face on the working one. The condition rating of 6/10 is mostly because one is fully functional, but the other is not. The working one comes with eight tubes testing at full strength, while the non-working one will not include tubes. We sent them both out to be repaired and one came back in perfect working condition, but the other is still non-functioning. The only info we have as to what is wrong with the second one is that the "front end is messed up and all part numbers are shaved off". The parts in the last picture are the pieces that were taken out of the functioning amp. These are available for local pick up only since we do not have any original packing materials. Feel free to inquire about a third party crate & carriage quote if you are interested in shipping.

Specs:
POWER OUTPUT
300 watts minimum continuous at 8 ohms from 16Hz to 20kHz with less than 0.8% total harmonic distortion (typically below .005% at 1 watt). Approximate actual power available at "clipping"; 330 watts (1kHz). (Note that actual RMS 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) 10Hz to 60kHz
FREQUENCY RESPONSE
-
INPUT SENSITIVITY
0.9V RMS for rated output
INPUT IMPEDANCE
60k ohms, nominal
OUTPUT TAPS
1,2,4,8 ohms
OUTPUT REGULATION
Approximately 0.3dB, 8 ohm load to open circuit
OVERALL NEGATIVE FEEDBACK
20dB
DAMPING FACTOR
Approximately 30
DISTORTION
-
SLEW RATE
25V/µs
RISE TIME
3µs
HUM & NOISE
Less than 2mV RMS 90dB below rated output (broad-bandwidth unweighted, inputs shorted)
POWER SUPPLY ENERGY STORAGE
Approximately 350 joules
POWER REQUIREMENTS
105-125VAC 60Hz (210-240VAC 50Hz) 900 watts at rated output. 450 watts at "idle" - 130 watts at "standby"
TUBE COMPLEMENT
(4 matched pairs) 6550 power output
DIMENSIONS
19" (48 cm) W (standard rack panel) x 10½" (27 cm) H x 16" (41 cm) D (front panel back). Handles extend 1 ⅝" (4.1 cm) forward of the front panel. Output connector extends 1" behind rear panel.
WEIGHT
110 lbs. (50 kg) Net; 126 lbs. (57 kg) Shipping

Local Chicago buyers are required to pay Illinois sales tax.