The Momentum M400 MxV Mono amplifier ($79,500/pair) 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 in May 2023. 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.

Richard Strauss: Four Last Songs; Final Scene from Capriccio; Mahler: Symphony 2 (Resurrection); Various composers: Maria Mater Meretrix; Prokofiev: Symphony No.5.

Ingrid Laubrock: The Last Quiet Place; Wayne Escoffery: Like Minds; Tony Kadleck Big Band: Sides.

Laurie Styvers: Gemini Girl: The Complete Hush Recordings; A Certain Ratio: 1982; The Wood Brothers: Heart Is the Hero; The Damned: Darkadelic; Stephen Stills: Live at Berkeley 1971.

In 2009, Robbie Fulks decided to make a change. For almost 20 years, the singer/songwriter had led a series of hard-hitting country-rock bands across America and beyond, his blistering guitar chops and madcap levity (the latter frequently testing, if not violating, standards of taste) winning him a modest-sized but ardent fan base.

"I was fatigued from what I'd been doing," Fulks told me recently via Zoom, sitting in his kitchen in Atwater Village, a Los Angeles neighborhood between Glendale and Burbank. "Me on acoustic guitar, with electric guitar, bass guitar and drums, that was my sound for something like 13 years. I was so tired of it, I was actually thinking of doing something other than music."