audio research
M300

Description
Hybrid tube/FET mono power amplifier.

Introduced
1987

Discontinued
1989

Revisions
M300 MKII (1988)

Options
A triode version producing 140 watts per channel was available for M300 MKII at an additional $2000.

MSRP (US new retail)
$9,800/pair
$11,995/pair (M300 MKII)

Specifications

Power output 300 watts continous at 8 ohms, from 16Hz to 25kHz with less than .5% total harmonic distortion (typically below .005% at one watt). Clipping: 330W at 1kHz, nominal.
Power bandwidth 10Hz-60kHz
Frequency response  
Input sensitivity 0.9V in for 300W out
Input impedance 60k ohms.
Output taps 1,2,4,8 ohms
Output regulation  
Overall negative feedback 20 dB
Damping factor 30
Distortion THD: 0.05% at 1W output
Slew rate 25V/µs
Rise time 3µs
Hum & noise Less than 2mV RMS; 90dB below full output
Power supply energy storage 350 joules
Power requirements 130W on standby, 450W quiescent (no signal), 900W at rated output power
Tube complement (4 matched pairs) 6550
Other  
Dimensions 19" W x 10.5" H x 16" D
Weight 110 lbs. Net, 126 lbs. Shipping.

Reviews

Issue 48 (M300: Special Report), Issue 50 (M300: Capsule), Issue 51 (M300 MKII: Special Report), Issue 55 (M300: Full Review)
Vol. 10 No. 9 (M300), Vol. 11 No. 1

Pictures

M300:

M300 MKII: