Measurements
Our measured figures suggested the lowest internal impedance of any DAC or music player we’ve yet measured, with the output voltage falling by less than 0.15dB for loads of 32.6 ohms compared to 552 ohms.
The output in milliwatts into the 552-ohm load was 6.5 (8.2dB above 1mW) and into 32.6 ohms it was around 110mW (20.5dB above 1mW).
For CD-style PCM audio, the noise level was -97.4dBA (I measured all these when it was running on battery) while the THD +noise level was less than 0.001%. As shown in the top graph here, the output was down by just 0.2dB at 20,000Hz, with a sharp filter kicking in immediately aerwards.
With 24-bit sound the noise was at -107.1dBA and the THD a bit lower. With 96kHz sampling (second graph) the response rolled smoothly and relatively slowly o, -0.3dB at 20kHz, -0.8dB at 30kHz and -1.6dB at 40kHz. The -3dB point was slightly above 45kHz.
For tracks with 192kHz sampling or DSD128 (third graph), the response was much the same as at 96kHz up to 40kHz, with -3dB at 51kHz. For DSD64, the output was -3dB at 42kHz.