DACs — Lotoo Gungnir

The Gungnir is a desktop DAC, line preamplifier and headphone amplifier from Lotoo, the Beijing-based maker better known for its PAW portable players. It combines digital conversion, balanced and unbalanced line outputs and a high-current headphone stage in one compact aluminium case, with left and right channels built as fully independent circuits that each have their own analogue power supply and discrete modules. Lotoo lists it at USD 3,400.

Key specs that matter

The converter section uses two AK4499EX converter chips fed by two AK4191EQ digital filter chips, so the delta-sigma modulator is separated from the analogue current output stage. An AK4137EQ sample rate converter and an ADI Blackfin BF706 DSP sit ahead of them, and playback reaches PCM 768 kHz and DSD512. Twelve Texas Instruments BUF634A buffers drive the outputs. At the balanced 4.4 mm socket the unit delivers 8,100 mW into 32 ohm, 3,100 mW into 100 ohm, 1,000 mW into 300 ohm and 520 mW into 600 ohm, with 132 dB A-weighted signal-to-noise ratio, 131 dB channel separation, a 1.2 uV noise floor and THD+N of 0.00025% at 1 kHz without load. Response deviates only +0.03 to -0.07 dB between 20 Hz and 20 kHz. The 3.5 mm single-ended jack gives 2,200 mW into 32 ohm and 130 mW into 600 ohm with 130 dB SNR. The case measures 183 x 175 x 63 mm and weighs 1.8 kg.

Engineering and use context

Digital inputs cover USB-C, AES/EBU on XLR, coaxial and optical, and the same three S/PDIF formats are repeated as digital outputs, so the Gungnir can also pass a signal on to another converter. Analogue line outputs come on XLR and RCA, and headphones also get a 6.35 mm unbalanced jack and a 4-pin XLR balanced socket. Gain has four steps, reaching +27 dBu on the balanced output in high gain and +4 dBu in low gain. A 5 cm TFT screen shows settings, and the DSP runs Lotoo's LCC load capacitance compensation, the PMEQ II parametric equaliser and ATE processing. Lotoo's LTTP wireless link carries 48 kHz/24-bit fully lossless or up to 96 kHz/24-bit high-resolution streams. Power arrives over USB-C PD 3.0 at 20 V and 3 A, and the optional LPX-01 base is a 160 W PD supply with four-stage filtering and 200 uV output noise up to 40 kHz.

Pairing

With ample power into high loads, high-impedance dynamic headphones are covered as well as current-hungry planar models on the balanced output, while in-ear monitors with high sensitivity are better served by the low-gain position. Its XLR and RCA line sockets connect directly to power amplification or self-powered loudspeakers.

Alternatives

The Lotoo PAW S2 is the brand's compact USB DAC and headphone amplifier, built on an AKM AK4377 chip with PCM up to 384 kHz, DSD128 and up to 150 mW into 32 ohm from its balanced output.