STEREO Magazin on the Moonriver Model 404

Tom Frantzen opens his STEREO 2/2024 review with an honest disclosure: Moonriver wasn't on the magazine's radar — and that's largely a function of how recently the Malmö house started shipping. The Model 404, the brand's first and central product, took roughly three years of development under designer George Polychronidis, a Greek-born industrial designer and HiFi engineer who values "naturalness, emotion, and flow" above the deliberately dry sound of studio monitors.

Inside the chassis

The 12.5 kg chassis (43 × 13.5 × 40.5 cm) wears its retro cues plainly — matte-black front, four glossy black rotary controls reminiscent of Sansui's 70s-era integrateds, two toggle switches, dimmable LED, and short wood "cheeks" that double as small rack ears. Up to four relay-switched line inputs are available; one each can be sacrificed to optional MM/MC phono and HiRes USB-DAC modules. There is a balance control, a mono switch, a tape loop, and two pre-outs for bi-amping. No headphone output — Frantzen's main quibble for apartment dwellers.

Under the hood, a generous toroidal transformer with five secondaries feeds an armada of fast filter capacitors totalling roughly 50,000 µF for the transient response. The output devices are Class A/B chip amplifiers on a shared heatsink — "verblüfft etwas" (mildly astonishing), Frantzen writes, but justified by the shorter signal paths and the absence of any SMD parts. Everything else is hand-built through-hole.

“Der Moonriver serviert selbst erfahrenen Testern musikalische Aha-Erlebnisse.”

— Tom Frantzen — STEREO Magazin

Skandinavische Magie

Despite the gentle name, the 404 isn't a wallflower — STEREO's lab measured 53 W continuous and 65 W impulse into 4 Ω, and Frantzen reports the amp going at it "wie der Teufel, mit mächtig Verve." Driving DALI's Epicon 6, the soundstage was huge, well-detached from the speakers, broad and deep, and "never even close to running out of breath." Cara Dillon's vocals reached well above the amp's price class; even a far more expensive Symphonic Line RG 14 Edition couldn't pull the 404 off pace.

When to look elsewhere

If your room is large and your speakers are inefficient, push the 404 hard and intermodulation distortion climbs into the high single-digit percent — and it shows. For everyone else — "Genussmenschen with musical ambitions and a taste a little above the mainstream" — the recommendation is unambiguous.

Verdict

Klang: gut 1.6 — "aufregend dynamisch, plastisch, natürlich, offen und mitreißend." Test result: gut 2.3. From €3,500. Frantzen closes with the line that matters: "Dieser Verstärker macht definitiv süchtig" — this amplifier is definitely addictive. Switch to anything else after a few hours with the 404, he warns, and the alternative will sound flat-out boring.