SMSL SU-1 MQA-CD TECHNICAL The SMSL SU-1 features the AKM AK4493S DAC chip supporting PCM up to 32-bit/768kHz and DSD512, in addition to supporting MQA decoding, whilst the iFi Audio ZEN DAC V1 features a Burr-Brown True Native chipset that supports PCM and DXD up to 32-bit/384kHz, and DSD256.
As a DAC/AMP combo, the iFi ZEN DAC is inherently more feature-rich than the SU-1. Since it comes built-in with an amplifier as well, the ZEN DAC also comes with a 6.35mm SE out, as well as a balanced 4.4 Pentaconn output.
For the sake of this comparison however, we will be neglecting the amplifier performance of the ZEN DAC and comparing it strictly as a DAC via its RCA outputs with its output mode set to fixed.
The ZEN Dac only has a sole USB-B input connector, compared to the three inputs present in the SMSL SU-1. Both units are powered via USB, however, the ZEN can also be powered with an optional 5V barrel jack.