The coaxial output of CD player is digital, which needs to be decoded into analog signal output through the coaxial input of decoder.

The coaxial and optical fiber outputs of CD players are digital signal outputs, and there is no digital-to-analog conversion (no decoder decoding).

If used by a linear power amplifier, it must be used by an external decoder. The four groups of output of CD player are optical fiber and coaxial, RCA and balance, the first two groups are digital signal output and the last two groups are analog signal output.