No one does multi-room audio better than Sonos, but its wireless speakers are limited when it comes to stereo. The Sonos Play:5 is a great speaker, for instance, and you can link two units together to create a $998 stereo pair. But if you buy a $599 Sonos Amp, you can use any conventional loudspeakers that spark your fancy. And perhaps more than two.
Sonos is coming full circle here, as its very first retail product was a small amplifier dubbed the ZonePlayer 100. That was succeeded by the ZP120, which was later renamed the Connect:Amp (now discontinued). The new Sonos Amp is light years ahead of those products, both in terms of specs and performance. I still have a ZP120 at home, but I haven’t used it in years because it’s so underpowered, delivering just 55 watts per channel.
The Sonos Amp isn’t aimed at casual music listeners. That market is better served by Sonos’s wireless speaker lineup: The Sonos One smart speaker, the simpler Play:1, and their big sibling, the Play:5. The Sonos Amp is designed for audio enthusiasts who want to blend the music-streaming convenience and multi-room audio capabilities that Sonos is so well known for with a high-end amplifier and conventional high-performance loudspeakers. The Sonos Amp is designed for critical listening in stereo, and for movie soundtrack experiences that are a cut above what you’ll get from the typical soundbar.
Driving speakers with the Sonos Amp
The new Sonos Amp not only delivers more power—125 watts per channel into an 8-ohm load—but it’s also outfitted with HDMI (with ARC), so that it can connect directly to your TV. In this scenario, the Amp can drive wired front left and right channels, any other pair of Sonos wireless speakers (apart from Sonos soundbars) as surround channels, and a wireless Sonos Sub (or any wired powered sub connected to the Amp) for low-frequency effects. If your TV is equipped only with an optical output and not HDMI, Sonos sells an adapter you can use.
If you have a large home theater, you can use both a Sonos Sub and a powered wired sub at the same time, and/or a second amp to power wired surrounds. The one thing you won’t get is a true center channel, but the Amp creates a convincing phantom center channel by blending the audio from the left and right front speakers. I certainly didn’t miss having a dedicated center channel in my movie tests.
The Sonos Amp can also handle wired speakers that present less than 8 ohms of impedance, producing up to 187.5 watts per channel while driving a 6-ohm load and a whopping 250 watts with 4-ohm speakers. The Amp can accept standard banana plugs or you can use its robust binding posts with bare wire (between 10 and 18 AWG). In the latter configuration, you can wire two pairs of speakers to the Amp in parallel to deliver the same music to two stereo pairs (with speakers in the same or in different rooms), provided the impedance presented to the amp doesn’t drop below 4 ohms.
The Amp’s binding posts are ingeniously designed so that you can pull them out of the Amp, thread bare wires through the posts, cinch them down, and then plug them back in. That’s much easier than having to reach around to the back of the amp to do everything. If you’re using banana plugs, you won’t need the binding posts at all because you’ll insert the banana plugs straight into the Amp. When driving Sonos by Sonance speakers (in-wall, in-ceiling, and outdoor models are available), the Amp can handle up to three pairs of speakers wired in parallel.
The Sonos Amp’s physical design
The Amp has left and right analog RCA audio inputs and a subwoofer output, but I suspect most people will use the wireless Sonos Sub with the Amp. Sonos didn’t build a phono preamp into the Amp because it assumed vinyl veterans would already have a phono pre-amp they like, while LP neophytes would start out with a turntable that has a built-in phono pre-amp.
There is also a pair of 10/100 ethernet ports in back, so you can hardwire the Amp to your network for maximum reliability if you have the infrastructure for it. Having two ports means you can daisy-chain a bunch of Amps to your network while needing just one ethernet cable from your router. It’s also possible to use the Amp as a network switch or a wireless bridge if the Amp is operating SonosNet, but Sonos doesn’t recommend this because the Amp’s quality-of-service settings will prioritize Sonos data traffic over anything else.
There are touch-sensitive controls on the front of the Amp for play/pause and volume up/down, but I don’t imagine these will see much use since the Sonos app is so much more convenient. You can also control the Sonos Amp using Amazon Alexa or Google Assistant, just as you can do with other Sonos components, but you’ll need a smart speaker (or the appropriate mobile app) to do that because the Amp doesn’t have a microphone of its own.
The Amp’s enclosure is designed to draw air in from the bottom and vent it from its concave top, a passive cooling strategy that allows several Amps to be stacked on top of each other without fear of them overheating (though I would err on the side of caution and add some active ventilation if I was stacking them in an enclosed entertainment center).
The Sonos Amp is ostensibly a retail product, but it was designed to also address the needs of custom installers who might mount a bunch of them in a component rack. The Amp measures 1.5 RU high (2.52 inches) and is 8.54 inches square. This enables them to be mounted two abreast in a standard 19-inch rack.
The Amp doesn’t have rack-mount ears, but it is outfitted with a standard M5 thread mount on its bottom. At a press event at Sonos’ Boston headquarters late last year, Sonos Amp product manager Benji Rappoport showed me an actively cooled rack cabinet holding 32 Amps.
Sonos Amp listening tests
I first tested the amplifier with four very different stereo speaker pairs, one pair at a time. I used Q Acoustics’ Concept 20 bookshelf speakers (6 ohms nominal impedance) in my home theater; Bowers & Wilkins’ 603 tower speakers (8 ohms nominal impedance, also in my home theater); B&W’s M-1 Mini Theatre satellite speakers (8 ohms nominal impedance) mounted high on a wall in my great room; and Focal’s Custom OD 108 outdoor speakers (8 ohms nominal impedance) mounted high on a wall in my enclosed patio. For the tests with the M-1 Mini Theatre (the smallest of the three sets of speakers by far), I paired the Amp with a Sonos Sub.
The Amp performed like a champ with each set of speakers. Volume didn’t get loud enough to drive me out of the room while listening to the two-way Q Acoustics bookshelf (1-inch tweeters and 5-inch woofers) or the three-way B&W tower speakers (1-inch tweeters, 6-inch mid-range, and dual 6.5-inch woofers), but both combinations easily filled my home theater without the need to crank the volume to the max.
Listening at more moderate—and realistic—volume levels that would permit folks to talk to each other at a party, I played the title track to Lyle Lovett’s Step Inside this House (ripped from CD and encoded in FLAC) and the amplifier produced Lovett’s vocals clear and strong against an engaging backdrop of guitar, pedal steel guitar, and bass.
The B&W M-1 Mini Theatre satellites are smallish two-way speakers (1-inch tweeters and 4-inch mid-range/woofers), and they came across as very bright on their own while I was listening to “Send My Love (to Your New Lover),” from Adele’s album 25 (also ripped from CD and encoded in FLAC). Note that the Sonos app provides very limited EQ adjustments: It has sliders to boost or cut bass and treble, and to adjust the left/right balance, but that’s all.
I’ve always augmented the M-1s with a Sonos Sub paired with a Sonos One smart speaker in a bedroom on the other side of the wall (the Sub can’t operate on its own, it must be paired with another Sonos component). The M-1s themselves are usually driven by an Onkyo M-282 stereo power amp wired to a Sonos:Connect. Yes, that’s a weird scenario for Sonos components, but it works great for me—thanks in no small measure to Sonos’ exceptional networking technology that keeps all the audio streams in perfect sync.
While testing the Amp with the M-1s, I linked the Sonos Sub to the Amp instead. You can use Sonos’ excellent Trueplay technology to tune its Sonos by Sonance architectural speakers (provided you have an iOS device, that is), but that option isn’t available with third-party speakers. Sonos nonetheless gives you an opportunity to tune the Sub to the room you’re using it in (and by extension, to the loudspeakers you’re using it with).
This is accomplished in two steps, starting with a simple A/B test that lets you correct the Sub’s phase. In the second step, you can further boost or cut the Sub’s output. If you’re not satisfied with these tuning results, you can adjust the Sub’s level, its crossover frequency, and its phase in a dedicated setting you’ll find elsewhere in the app.
The Focal Custom OD 108 are large outdoor speakers, equipped with a bass reflex port, an 8-inch fiberglass woofer, and a 1-inch aluminum inverted doom tweeter. There was absolutely no need for the Sonos Sub while driving these bad boys with the Sonos Amp, but I was impressed with how great the combination sounded while listening to Lucinda Williams sing “I Envy the Wind,” from her album Essence. Even at lower volume levels, Williams’ voice, quavering with longing, came across with authority.
My unconventional use of Sonos components
I later tested the Sonos Amp driving the Q Acoustics, B&W Mini Theater, and Focal Custom OD 108—plus the Sonos Sub—all at once, having wired the passive speakers to a Niles Audio SS-4 speaker selector box. In this scenario, each of the three speaker pairs is wired inline to a Niles Audio impedance-magnifying volume control that’s built into an adjacent wall. In addition to providing independent volume control for each pair of speakers, this device prevents the impedance presented to the amplifier from dropping too low, a scenario that could damage the amplifier. The Amp never broke a sweat driving the speakers individually (selected one at a time on the Niles Audio SS-4) or all three pairs at the same time (with all the speakers selected on the box).
Sonos’ take on this arrangement, however, is that it doesn’t deliver the best listener experience. The company recommends instead that consumers deploy one Amp for each room, and that they use the Sonos software as the speaker selector. They have a point—to a degree: My setup can’t play different music in each room, and without the in-wall volume controls, all the speakers would play at the same level.
But apart my home theater, my home’s open floor plan would make it difficult to isolate the great room, the kitchen, and the enclosed patio from each other anyway—music from one will bleed into the others at almost any volume level. In any event, the setup I’ve come up with works for me in the same way my unconventional Sonos Connect/Sonos One/Sonos Sub configuration does. More importantly for anyone thinking of following my example, it doesn’t void the warranty on the Amp.
Is the Sonos Amp worthy?
The Sonos Amp isn’t the right solution for everyone, a point that Sonos need not be embarrassed about. In fact, I suspect most Sonos Amp sales will go to custom installers, just because so few people want to deal with speaker wire these days. But if you’re a true audio enthusiast who wants all the power and flexibility of a Sonos multi-room audio system, and you want higher-end loudspeakers than what Sonos has to offer (in terms of wireless speakers, that is, as I haven’t listened to anything in the Sonos by Sonance lineup), the Sonos Amp is a fabulous choice that will drive any passive loudspeakers you own.
Another alternative would be to go with a Sonos:Connect and a pair of self-powered speakers (or a Connect, an outboard amplifier, and passive speakers), but the Amp is simpler and more elegant—especially if you’re connecting it to a TV. It’s incredibly well engineered, supremely easy to set up and use, and it sounds positively divine.