Integrated amplifiers — Naim UNITI ATOM

The Uniti Atom is the most compact all-in-one streaming amplifier in the second-generation Uniti family from Naim Audio of Salisbury, England, combining a network player, DAC, preamplifier and stereo power amplifier in a box under 25 cm wide. Naim announced the new Uniti models together, with shipping of the range scheduled from the third quarter of 2017 in a staggered rollout, and later used the Atom as the base for a headphone-oriented edition.

Key specs that matter

Its Class AB power stage delivers 40 W RMS per channel into 8 ohm at 0.1 percent THD+N. Digital inputs are two TOSLink optical sockets up to 24 bit and 96 kHz and one coaxial RCA up to 24 bit and 192 kHz with DSD64 over DoP, next to one analogue RCA pair and a USB port for sticks up to 128 GB or portable SSDs up to 1 TB holding as many as 20,000 tracks. The streaming engine plays WAV up to 32 bit and 384 kHz, ALAC, FLAC and AIFF at up to 24 bit and 384 kHz, and DSD64 and DSD128, gapless in every format. Outputs cover the speaker terminals, an RCA sub or pre output and a 3.5 mm headphone jack. Normal consumption is 90 W, falling to under 2 W in network standby. The enclosure measures 24.5 cm wide, 9.5 cm high and 26.5 cm deep and weighs 7 kg.

Engineering and use context

Naim says the power stage uses technology derived from its NAIT integrated amplifiers. Decoding runs on a fourth-generation 40-bit SHARC DSP with Burr-Brown converters, 16 times oversampling and digital filtering, and level is set by a digitally controlled analogue volume stage. The CNC-machined aluminium case has heavy side heatsinks coupled directly to the floor pan of the unit, and the Wi-Fi aerial is hidden behind a slot cut into one heatsink. Naim listed an HDMI ARC input for TV sound as an option on the Atom, galvanically isolated to keep noise from the television out of the circuit. The top carries a rotary volume ring with a proximity sensor that wakes the 12.7 cm colour LCD, plus four buttons. Services include AirPlay 2, Chromecast built-in, Spotify Connect, TIDAL, Qobuz, Roon Ready, UPnP, internet radio and aptX HD Bluetooth, and control is via the Focal and Naim app, a Zigbee RF remote or Control4, Crestron, Elan, RTI and Savant systems. Wi-Fi is 802.11ac, Ethernet runs at 10/100 Mbps, and Party Mode links up to six Naim streamers.

Pairing

Given its moderate output, the Atom is best matched with passive speakers of reasonable sensitivity. The sub or pre output feeds a powered subwoofer, active speakers or a larger external power amplifier, and a turntable can use the analogue RCA pair once it passes through a separate phono stage.

Alternatives

The Naim Uniti Nova is the larger all-in-one of the same Uniti generation, with 80 W per channel.