DACs — Fosi Audio ZH3

The ZH3 from Fosi Audio combines three jobs in one aluminium alloy desktop chassis - USB and S/PDIF conversion, headphone amplification and line-level preamplification. It belongs to the Z-Series family alongside the ZD3 and ZA3, with a list price of USD 199.99. Headphones, in-ear monitors, active speakers and power amplifiers can all be driven from the same box.

Key specs that matter

The ZH3 decodes with an AKM AK4493SEQ chip fed by an XMOS XU316 USB interface, with four OPA1612 dual op-amps in the analogue stages. PCM is accepted up to 32 bit and 768 kHz and DSD up to DSD512. Fosi quotes SINAD of at least 115 dB, SNR of at least 121 dB, THD+N no higher than 0.00018 percent, a noise floor of 1.9 microvolts and 117 dB of crosstalk. The 4.4 mm balanced headphone jack delivers 2,570 mW per channel into 32 ohm, while the 6.35 mm single-ended jack gives 640 mW per channel into the same load. A three-step gain switch covers headphones from 16 to 300 ohm. Inputs are USB, coaxial, optical and analogue RCA, and line-level outputs are XLR and RCA.

Engineering and use context

Two of the op-amps sit in sockets as DIP8 dual-channel parts, so owners can swap them for types such as the LME49720, NE5532, MUSES02 or SS3602. Six digital filter types can be chosen, and a tone section gives plus or minus 12 dB of bass and plus or minus 10 dB of treble, with a bypass mode that takes it out of the path. The USB port runs in UAC 2.0 for computers and can drop to UAC 1.0, which lets consoles such as the PS5 and Switch connect without drivers. Status appears on a 38 mm LCD, and one orange multi-function knob handles volume and output switching. An infrared remote changes inputs and outputs and sets a 30 minute auto power-off timer, and the unit remembers its last volume. A 12 V trigger input and output let it wake and sleep in step with connected equipment. The box ships with the remote, USB cables, an adapter, a trigger cable and an external power supply.

Pairing

The balanced XLR outputs and trigger link make the ZH3 a natural front end for a Fosi ZA3 power amplifier, while the RCA outputs suit powered monitors. Low-impedance in-ear monitors fit the lowest gain step, and hard-to-drive planar or high-impedance headphones benefit from the balanced jack.

Alternatives

The Fosi Audio ZD3 is a balanced desktop DAC and preamplifier built around an ESS ES9039Q2M chip, with Bluetooth and HDMI ARC inputs but no headphone amplifier.