Integrated Amp Reviews

My first car was a decrepit, mustard-yellow Peugeot 304 with a navy hood. The blue hue wasn't a fashion statement; after an accident, the previous owner had gone to a salvage yard where only a blue replacement could be procured. When he grew sick of the car—because it made him look "like a frickin' ad for Ikea"—I paid him 600 Dutch guilders for the old heap, the equivalent of about $300 US.

Nothing worked as it should. The stalk for the blinkers was missing; I substituted a screwdriver. The radio was like a wavering zombie: dead one day, sputtering to life the next. I got well acquainted with jumper cables. One day, I opened the trunk and found tiny mushrooms sprouting from the carpet.

On the plus side, I never received a speeding ticket: The engine smoked if you drove faster than 45mph, so I didn't.

Years later, when I got into hi-fi, I thought of that car and subsequent ones. What stood out to me most about high-end audio was: separates. Rather than gravitate toward worthy one-box solutions, audiophiles seemed obsessed with splitting things apart. They had to have a standalone power amp, preamp, sources, speakers, cables. "What if you bought a car that way?" I thought to myself. A suspension from one manufacturer, a chassis from another, wheels from a third—and yes, a used blue hood from a junkyard. Seems pretty mental. No thanks.

It's not a precise analogy, I realize. When you have to get from point A to point B, you buy a one-box automotive solution. Bolting together mismatched car parts wouldn't work at all. Audio, on the other hand, is more or less standardized. Most components are easily connected, and they work together reasonably well. Still, even if you forgo 1950s all-in-one consoles (footnote 1), '70s receivers, and (ugh) '80s boomboxes, why can't the desire for great sound be sated with a single-box fix, just like transportation? Just please give me something that works better than my French jalopy did.

Everything you need (almost)
For roughly half a decade, we've seen a spate of products that do precisely that. The Naim Uniti Atom is a great example; so are the T+A Cala and NAD's Masters Series M10 and M33. Everything you need in one box—just add speakers (footnote 2).

Korea's HiFi Rose recently joined the fray with the RS520. Conceptually, it's the love child of HiFi Rose's RA180 GaN FET class-D integrated amplifier ($6995; footnote 3) and the RS250A network streamer ($2695). Combining a well-thought-out streaming device, DAC, preamp, and amplifier, the unit is as versatile and full-featured as you could wish. Okay, not quite: The RS520 has no silver-disc transport, no headphone output, no subwoofer outputs, no balanced ins or outs, no phono stage. With those caveats out of the way, let's take a look at the laundry list of technologies and features that RS520 buyers do get.

Milled from a block of aluminum, the RS520's casework (in silver or black) is classy and understated. Both the left and right flanks have 11 shallow ridges that improve heat dissipation. On top, to each side of the word "Rose" engraved in the center, is a cluster of three silver-rimmed vents that further help with cooling. Also on the top, near the front edge, are four narrow silver buttons, each about an inch long. From the left, the first three are Mute/Unmute, Volume Down, and Volume Up. The fourth control is a power button that, with a long press, lets you turn off just the screen while keeping the component fully active.

Located on the right of the rear panel, the binding posts are spaced far enough apart to accommodate large spades. Moving to the left, we see TosLink and RCA S/PDIF ports (inputs and outputs), an eARC input, an RJ45 connection, a USB-B input, an analog-input RCA stereo pair, and three USB 3.0 A-style inputs. (The middle one is reserved for the included Wi-Fi/Bluetooth antenna; the other two can be used to attach storage.) Rounding out the connections are an HDMI output, RCAs for the preamp out, the usual trigger and infrared control ports, a ground terminal, and a 15A IEC socket.

Inside, HiFi Rose says, the analog and digital circuits are mounted on separate boards to prevent digital noise from affecting analog signals.

The bottom of a stereo component rarely warrants attention, but here there's an empty bay on the bottom for a 2.5" solid state drive (not included).

I've saved the best for last. The fascia is entirely taken up by the biggest display I've ever seen on a stereo component—apart, that is, from HiFi Rose's own RS150B streamer ($4995), which is even wider than the one on the RS520. After you subtract the 0.6" bezel, the 520's screen measures a whopping 12.25" × 3.5". The screen is the component's main attraction in terms of shelf appeal.

The competition has taken notice. At a recent audio show, the rep for a leading brand of streamers told me that he regards the RS520 as a "big disruptor" due to its aggressive price and expansive screen. Suddenly, other streamers' displays seem puny by comparison.

As friends dropped by to see my newly built listening room and hang out and play some favorite recordings, every single one commented on the HiFi Rose. They approached, swiped, tapped, grinned. And why not? I mean, you can set the jumbo LED display to mimic a Nixie clock (footnote 4) or the fascia of a full-size FM tuner. When streaming audio, a couple of taps on the screen produce virtual VU meters—your choice of designs and colors (footnote 5). Perhaps it's a little silly, but it's thoroughly charming. I've admired many audio products that passed through my home, but I don't think I've ever had as much fun with one (footnote 6). "That thing is cool!" was my visitors' shared verdict.

I did encounter one naysayer, though not in my home. "Who needs an iPad stapled to their amp?", a gentleman on an online audio forum bristled. It was pointed out to the sourpuss that the RS520's screen can be turned off, as I often did; I like listening in the dark.

Jon Derda of MoFi, HiFi Rose's distributor, believes the two companies have a winner on their hands. "In addition to sound quality, there are two differentiators that jump out" about the RS520, he wrote in an email. "The first is the front panel. Being able to read the name of the song from across the room is a practical benefit that components with small screens can't provide."

No kidding. The RS520 is the first audio component with a screen that lets me easily read the song title and artist's name from my listening position, 13–14' from my gear. Just a quick glance; no squinting.

The second big distinction, Derda says, is the power of the amplifier: a specified 250Wpc into 8 ohms or 4 ohms. "Many components in the all-in-one category deliver 50 to 100 watts per channel. The amp in the RS520 can drive a much wider range of loudspeakers than the other one-box solutions."

He's not wrong, although I'll note that the $5999 NAD M33, which I reviewed for a different publication, comes close; it's specified to produce 200W of Purifi Eigentakt power per channel with an 8 ohm load. The NAD drove the several pairs of speakers I threw at it with exemplary punch and clarity. But sure: My Naim Uniti Atom streamer amplifier, which I love for its beautiful design and pristine sound, has a harder time with some less-sensitive speakers due to its much lower power output, specified as 40Wpc into 8 ohms. The T+A Cala, at 50Wpc (footnote 7) , is on the modest side as well.

Channeling a Swiss Army knife
The RS520 is Roon Ready and can handle every digital format I'm familiar with (AAC, AIFF, ALAC, FLAC, MP3, MQA, OGG, WAV, WMA) plus some I'd never even heard of. It supports playback of PCM sources up to 32/768 and DSD sources up to DSD512. The DAC is built around the excellent ES9038PRO Sabre chip, which claims –122dB THD+N and a dynamic range of 140dB. It's the same digital-to-analog tech you'll find in the RS150B, the company's flagship streamer.

Power comes from a GaN FET amplifier section that runs in class-D—although the Korean team, with a nod to the analog-ish sonics of the RS520, likes to refer to it as "Class-AD." GaN stands for gallium nitride. In semiconductors, the material has some major advantages over silicon, as JMu explained in her Stereophile review of HiFi Rose's RA180 amplifier: "GaN FETs respond faster to transients, dynamic swings, etc., with less overshoot and shorter recovery time. The result is faster switching times (with less 'dead time') and more precise switching with less ringing, distortion, and EMI (electromagnetic interference). Class-D designs use negative feedback to offset such distortion; silicon-based amps need quite a lot of it to perform at their best. Starting with more precise, faster amplification means that less feedback is needed." Sonically, it should all add up to "less harshness and more smoothness, improved detail, and a more neutral presentation."

After you press the 520's power button and wait about 25s for bootup to complete, you're greeted with a row of icons that give you access to your music. The 520 offers AirPlay 2, Spotify Connect, Tidal, Qobuz, Apple Music, and much more. Swipe left or right on the front panel, and you'll find icons that unlock Rose-specific content. RoseHome shows tracks that the algorithm thinks you'll like, plus a list of recordings you recently played. RoseRadio lets you access internet music stations around the world. RoseFM transforms the RS520's front panel into a near-photorealistic rendition of a 1970s-style tuner, complete with a ribbed horizontal frequency dial that's completely functional (but without the tactile feedback, natch).

RoseTube is a music-oriented, ad-free YouTube portal. That's right: You can play video on the 520's screen. Then again, why would you want to? Better to route the HDMI output to a big- screen, hi-def TV, should your listening room have one.

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Footnote 1: See tinyurl.com/ybkdzs7r.

Footnote 2: Or not: I like the Sonus Faber Omnia and love the Naim Mu-so; both have speakers built in.

Footnote 3: Although the two components look nothing at all alike.

Footnote 4: See en.wikipedia.org/wiki/Nixie_tube.

Footnote 5: Those colors no longer include "McIntosh blue," one of the 520's original VU meter presets. It seems that some folks in Binghamton objected.

Footnote 6: Until I read Rogier's description during editing, I'd thought of this design—of the RS520 and the two streamers in the HiFi Rose lineup—as rather boring. Now I know I was wrong. Thinking also of the very different but extraordinary-looking RS180, it becomes clear that hi-fi–rack wow factor is a big part of the HiFi Rose approach.—Jim Austin

Footnote 7: T+A specs say 2 × 100W, but that's into a 4 ohm load. Apples to apples.