Audio Research M300 monoblock power amplifier Page 7
On the 4 ohm setting the M300 spoke with undisguised authority, breathing an articulate, lively dynamic quality into the reproduction of recorded music and providing abundant depth where the source quality allowed.
The stereo presentation had an exceptional front-to-back dimension; the mildly "forward," larger-than-life front stage added to the great depth and ambience retrieval. Compared with many other amplifiers, the M300, like the SP11, sounded slightly "enhanced," spotlighting musical detail. This is an attractive quality, even if we consider it to be a slight departure from neutrality in absolute terms.
Considering the SP-11, the M300 was capable of exploiting a very large measure of that unit's audio quality, and the two make a fine, well-matched audiophile combination.
Conclusion: This is a giant of an amplifier, large enough for any known installation except for speakers with a cruel combination of low impedance and low sensitivity. The lab performance is extremely good, though I would like to see more consistency in the distortion results and the higher-frequency kinks in the transfer characteristic ironed out. It could be better still. Was this aspect the one which could be related to the subjective treble quality? I wonder...
Technically, the M300 certainly prefers driving loudspeakers from its lower-impedance taps, partially confirming the subjective results. As regards the latter, I am still surprised at the degree of quality shortfall on the 8 ohm tap (checked with several loudspeakers) and the general sonic excellence achieved when using the 4 ohm tap. As the power test results show, it is still massive on 4 ohms, and I would readily take this option given the results in my system.
The high quality of this amplifier and the relationship between the dollar price and US incomes make this UK-based reviewer a little envious of our American cousins' good fortune. In the UK the price in real terms is almost double, and yet the high review rating would stand virtually unchanged over here.
Transparency and depth are major features of the M300 when used at its best, and are complemented by high resolution of detail in both complex and low-level passages, plus an ability to separate individual instruments from the mix. Stereo focus and stage width are a little less than excellent.
Clearly a top-line product, this amplifier carries a strong recommendation, and its achievement suggests a long production life, punctuated by the usual progressive, evolutionary ARC developments.—Martin Colloms