Review: Technics SU-GX70 Network Amplifier

One of the coolest trends in the home audio landscape is a growing number of high-end network-ready amplifiers, able to serve up just about any content you could want using virtually any method—just add speakers.

The Technics SU-GX70 is one of the latest additions to this party. It’s packed to the brim with playback methods, from AirPlay and Spotify Connect to a phono input for your turntable and HDMI ARC to connect your TV. It also offers great looks and sound quality, making it an enticing new way to build out a sterling stereo setup.

Excluding the name itself, Technics took its time in designing the SU-GX70, crafting a digital interface that drops a swath of tech at your fingertips and focuses on preserving audio quality.

Pulling the unit from its packaging, I noticed it feels surprisingly light, especially compared to Naim’s weighty Uniti Atom network amplifier (8/10, WIRED Recommends), my primary reference amp. This is partly due to the GX70’s fully digital amplification circuitry, which doesn’t require the hefty heat sinks of Naim’s Class A/B-style amplifier.

The Technics feels almost like the polar opposite of the Naim, trading the latter’s stout and compressed black cabinetry for a long and relatively thin frame dressed in sparkling silver (though there’s also a black version).

Technics says its amplification system is designed to preserve high-resolution audio from start to finish while still allowing for the “soft texture” of analog audio. The company has added some cool digital tricks, including specialized circuitry to preserve TV audio from the HDMI ARC input, as well as digital correction software that can account for varying speaker impedance levels and adapt the sound for your room and speaker layout (the latter requires an iOS device).

The GX70 employs dual power circuits to separate the power sent to the digital amplifier from the rest of the electronics for a quieter signal. There’s also a special Pure Audio Mode designed to shut down the HDMI input and network connections when you’re listening to a direct-input signal, though this kind of defeats the purpose of all those input options.

Photograph: Technics

The GX70’s full swath of features are accessed via the Technics Audio Center app. First, though, you’ve got to use either the Google Home or Apple Home app to get the system online. It’s an odd (and mildly confusing) departure from the proprietary setup methods found in many of today’s network devices, but it worked quickly for me and provided a stable connection over weeks of use.

Within the app, you’ll find a relatively intuitive interface that lets you futz with tons of settings, choose inputs, and stream audio via services like Spotify, Tidal, Deezer, and others. You can add Favorites for quick access to a wide array of local and global radio stations or play directly from Spotify Connect, AirPlay 2, Chromecast, or Bluetooth. You can also stream hi-res audio files from a local server at up to 384 kHz/32-bit resolution or DSD up to 11.2 MHz.

The GX70’s spread of connection options is impressive and includes three digital inputs (two optical and one Coax), USB-B and USB-A, and good ol’ FM radio. Outputs include a front-facing headphone output, stereo speaker outs, and a preamp output for connecting a second amp or a powered sub. So yeah, you won’t run out of ways to play anytime soon.

If you prefer a more tactile means of control than the mobile app, the GX70’s long-wand remote harbors the majority of significant functions, though I wish it included backlighting. You won’t need it for TV control, though, as your TV remote lets you control power and volume when connected over HDMI ARC—just make sure to first adjust your TV’s audio output to PCM, or the amp will make horrible noises that could damage your speakers.

While the SU-GX70’s truckload of features understandably get the lion’s share of attention, when it comes to performance Technics has delivered a clear and capable amplifier behind all that flashy tech. With an efficient power plant of 40 watts per channel for an 8-Ohm load, the amp should have no trouble powering most speaker sets, from bookshelves to towers.

I tested the GX70 with three different bookshelf pairs, including the Bowers & Wilkins’ 606 S3 (8/10, WIRED Recommends), Focal Theva (9/10, WIRED Recommends), and Polk Legend L100. Across all three models, the Technics provided crisp and clear audio with excellent definition, a precise and well-defined stereo image, and impressive balance across frequencies.

Coming from the Uniti Atom, which costs nearly double what you’ll pay for the SU-GX70, I understandably had to adjust my expectations. The Technics doesn’t offer the same body and dynamic sound in the midrange and bass, nor does it provide a soundstage as expansive or dimensional as the one Naim’s black box delivers. There’s a reason the Uniti Atom is an audiophile favorite, but you’ll pay for that pleasure and get fewer inputs and settings into the bargain. That said, the Technics’ sound profile is also a departure from my other main setup, KEF’s LSX-powered bookshelves.

The trait that really caught my attention when I connected the SU-GX70 is its brighter and more clinical delivery. That was especially noticeable with TV content, where the amp brought a more forward tone and some ramped-up sibilance, with “S” sounds seeming to jump out a bit more readily in light audio productions. I got used to the tighter tone over time, and the amp is an especially good pairing with Focal’s smooth and silky Theva speakers, which provide great clarity without ever sounding sharp. The snappier B&W 606 S3 created a less amicable partnership.

When connecting U-Turn’s Orbit Theory (9/10, WIRED Recommends) turntable (I’ll be auditioning a Technics SL-1500C-W next, so stay tuned), I noted a drop in dimensionality and warmth over the Naim system, but again that’s to be expected at this price, and I was impressed by how well the GX70 holds up for the money. Albums like Elton John’s Tumbleweed Connection sound sparklingly clear, complete with all the creamy goodness of his piano and an impressive collage of twangy instruments across the soundstage in songs like “Amoreena” and “Where to Now St. Peter?”

While it’s important to pick the right speaker pairing, namely those with smoother sound profiles from brands like KEF or Focal, the SU-GX70 is a fun and versatile system. Its sweet mix of clear and detailed sound and gobs of features and connection options make it an enticing stereo centerpiece for budding audiophiles.