We support the bit-perfect output to optical SPDIF (up to 192 kHz, 24-bit). 

What's the bit perfect?

When WiiM Mini supports a bit-perfect function via digital optical output, it outputs the same bit depth and sample rate as your music source. I.e., if your source is 24 bit/192kHz, it will output 24/192. While if your source is 16-bit/48kHz, it outputs the same without up conversion. It uses the same sample rate/bit depth with your input source. 

How to setup the WiiM device?

Of course, your downstream optical receiver (DAC or amplifier) needs to have the ability to handle the specified bit depth and sampling rate. To keep compatibility with the legacy optical audio receivers, we set the maximal output to 48 kHz/16-bit by default. You can adjust the output up to 192 kHz/24 bit from the WiiM Home App. This can be done by selecting the device tab > tap the device setting gear icon > Select audio settings > SPDIF output resolution. Then select your target sample rate and bit depth, play the test audio to verify if your downstream receiver is able to receive it.