A second company, built around one name.

Dan D’Agostino Master Audio Systems is the second amplifier company of Dan D’Agostino, the engineer best known for Krell. English Wikipedia says Krell was founded in 1980 by D’Agostino and Rondi Halling, who later became Rondi D’Agostino, and that he left it in 2009. His own account of the exit is blunt: “I was forced out of my own company by a minority investor, who had no idea what he was doing,” he told Hifi Pig in 2020. After exhausting his legal options, he said, he started a new company “to focus on equipment delivering two-channel stereo performance of the highest order.”

His background is well documented. In a 2003 Stereophile interview, David Lander described a childhood a few blocks from Niagara Falls, where D’Agostino’s father, Frank, a machinist by training, ran an appliance store; the boy repaired washing-machine timers, installed car radios and, in his last year of high school, built a sound system for a neighbourhood bar. Krell’s first amplifier, the KSA-100, made 100 watts at a time when the benchmark Mark Levinson ML-2 was rated at 25, a point Lander put to him directly. The new company’s website adds that D’Agostino earned an electrical engineering degree at UC Berkeley and served with a U.S. Navy Underwater Demolition Team; we give those as its claims.

The new company’s starting date depends on who is counting. Its website says it was founded in 2011. When Stereophile’s Michael Fremer reviewed its first product in February 2013, he wrote that it had been shown “a year and a half after the split,” once a noncompetition clause had expired. In January 2026 the company held a 15th-anniversary event, at which Stereophile described Dan and Petra D’Agostino as its co-founders — Dan as chief design officer, Petra as chief operating officer.

Copper, billet aluminium and a watch-style meter.

The product that relaunched him was the Momentum monoblock amplifier. Reviewing it in Stereophile in February 2013 at $55,000 a pair, Fremer called it “his first new product since leaving Krell” and described a 5-inch-high, 95-pound amplifier rated at 300 watts into 8 ohms, 600 into 4 and 1,200 into 2. Its chassis was machined from a single billet of aluminium, with thick copper side panels bolted on; instead of cooling fins, the copper was drilled with double-funnel “venturi” holes that let hot air rise and draw cooler air in. D’Agostino told Hifi Pig that copper “is considerably more thermally conductive than conventional Aluminum,” which allowed a small amplifier with high output.

The face of the product was its meter. Fremer wrote that the large, round, up-tilted power meter, “with its 19th-century-style needle, is clearly based on classic watch designs,” and noted that D’Agostino is a watch collector, a wine enthusiast and a car buff. The company’s 2014 product copy described a meter “inspired by the styling of fine Swiss watches and bearing D’Agostino’s signature.” In January 2013 Stereophile reported that the Momentum, featured on the cover of its CES issue, could be heard in many rooms at that year’s Consumer Electronics Show.

Recognition followed. Stereophile wrote in January 2014 that the original Momentum monoblock had been a joint Amplification Component of the Year for 2013, and that the Momentum preamplifier had won CES 2014 Innovations Design and Engineering awards. The range has since grown into four series: Relentless at the top, Momentum, Progression, which the company calls “the gateway to serious sound,” and Pendulum, which it says brings its sound “to a whole new audience.” In January 2026 it unveiled the Momentum Z monoblock at $125,000 a pair; Stereophile reported that it replaces the Momentum M400 MxV, is rated at 500 watts into 8 ohms, uses copper heat fins and JFET input devices, and keeps what the press release called “the Momentum’s classic Swiss watch appearance” — now as a needle drawn on a 3.5-inch screen.

Design and documentation.

Beside the names that defined American high-end audio sits a second tier of smaller companies, most started by one designer or one family. Where they differ most is ownership.

Some are still led by their founders. Bel Canto Design says John Stronczer founded it in Minneapolis in 1991 and that its products are built there. Zu Audio, founded by Sean Casey, says its products are made in Ogden, Utah. Dan D’Agostino co-founded Krell in 1980 with Rondi D’Agostino, English Wikipedia says, and left it in 2009; his own company says it was founded in 2011 and builds by hand at Cave Creek, Arizona.

Others are family businesses. VTL traces itself to David Manley’s amplifiers of the early 1980s; in 1993 father and son parted, Luke Manley kept VTL, and it says all its products are made in Chino, California. Von Schweikert dates itself to 1975; its founder, Albert Von Schweikert, died in 2020, and his son Damon is listed as co-founder and CEO, with cabinets made in California, the company says.

Two have changed hands. Parasound, founded in San Francisco in 1981 by Richard Schram, was sold to David Sheriff in December 2022, the company says; its website now gives Las Vegas as its location. GoldenEar, launched by Sandy Gross in 2010, was sold by The Quest Group to PML Sound International, joining Paradigm, Anthem and MartinLogan from January 2025, GoldenEar announced.

This guide sets out what can be checked about each brand — who founded it, who owns it, and what it says about where its products are made — and marks clearly what rests only on the company’s own word.

From Weston, Connecticut, to Cave Creek, Arizona.

The company did not start in the desert. Stereophile’s 2013 review listed it as Dan D’Agostino Inc. of Weston, Connecticut, at the domain dagostinoinc.com, and archived 2014 pages of its website still described Momentum amplifiers as hand-built and tested in its “Connecticut factory” while giving shipping and billing addresses in Carefree and Cave Creek, Arizona. In January 2014 Stereophile reported that the new Momentum integrated amplifier was made in Carefree. Today the company, Dan D’Agostino Master Audio Systems, LLC, gives its address as Cave Creek, Arizona, and says its products are “hand built in the USA, by our team of dedicated technicians in our Arizona facility”; Stereophile attended the 2026 launch at that factory. We found no sale of the company and no outside owner in the sources we checked.

Krell, the company he left, had a harder end: English Wikipedia, citing Stereophile, says it closed in June 2024 following the death of its owner and chief executive, Rondi D’Agostino.

For a design guide, Dan D’Agostino shows how a designer’s name, one material and a single instrument-like dial can carry a whole range of products. Compare Krell, the company he co-founded, and Mark Levinson, whose 25-watt ML-2 was the benchmark Krell’s first amplifier answered. For this guide we use copper, billet silver and meter black with a geometric sans, an unofficial interpretation; no product or logo is reproduced.

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