The Momentum M400 MxV Mono amplifier ($79,500/pair)1 is the latest iteration of Dan D’Agostino Master Audio Systems’ debut amplifier of 2011, the Momentum Mono amplifier. Weighing 95lb, it is smaller and lighter than its entry-level sibling, the more powerful, 125lb Progression M550 Mono amplifier ($47,500/pair), and is veritably dwarfed by some other monoblocks, including the flagship D’Agostino Relentless Epic 1600 (570lb) and the Karan Acoustics POWERa mono (231lb), which I reviewed last month. But if the M400 MxV’s rock-solid look and feel and its exquisite aesthetics—a sleek amalgam of silver and copper fronted by a power meter that glows green and radiates Rolex quality—are any indication, a helluva lot is going on beneath its showy exterior.
Once I took a listen, I discovered sound so smooth and satisfying that the refrain “How ya gonna keep ’em down on the farm / After they’ve seen Paree,” from a WWIera song about soldiers not wanting to return to their family farms after experiencing big city life in Paris, kept playing on repeat in my head.
I’m always amused when my expectations are proved wrong. The strength and quality of bass with the M400 blew me away.
Direct from Cave Creek
What kind of amplifier is this that distracted me so from watering the cows and milking the chickens? D’Agostino’s website2 offered a few clues. The Momentum M400 MxV is hand built; it includes discrete, direct-coupled, balanced circuitry and boasts a “new, ultra-quiet 2200VA linear transformer” with a winding scheme that is said to reduce the hysteresis effect by 90%, minimizing power and thermal loss. The new winding method also plays a role in increasing current capability by more than 50% and “offer[ing] greater headroom during dynamic passages,” which is surely aided by a bank of nearly 100,000μF of supply capacitance. All that adds up to potential output power of 400, 800, and 1600W into speaker loads of 8, 4, and 2 ohms, respectively.
For additional insight, I turned to the man himself, Dan D’Agostino, whose early designs (with Krell Industries,
