From Antipodes Audio support:
"It is true that S/PDIF and AES3 outputs have limited bandwidth compared to the full-bandwidth available with USB, Ethernet and I2S. However, there are downsides to having Ethernet and/or USB receivers in the DAC. Both introduce noise into the DAC. USB has the effect of adding a trace of ‘sizzle’ at the edge all sounds, creating some listener fatigue. Ethernet has the effect of rounding the edge of all sounds, diminishing the tension and urgency of real music. The extent of these problems depends on how well these inputs are implemented in the DAC. If you compare these outputs to our S/PDIF and AES3 outputs you will hear the benefits in naturalness and musicality for yourself."
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The manufacturer of my DAC says the Ethernet input is the best sounding. What are my best options?
You cannot take such claims literally. Your DAC manufacturer is, at best, making a generalisation, because comparing Ethernet with other inputs includes comparing the player engine and app in the DAC with the player engine and app in the Music Server. If a DAC manufacturer has not compared their inputs using a K50 then they are making a generalisation that you should not accept blindly. In our experience most DAC manufacturers are assuming you will use a standard computer as your music server.
We cannot know that the player engines in Antipodes products are better sounding than those in all DACs ever made, or still to be made, so we won’t make any generalised claims. The same goes for doubting DAC manufacturers’ generalised claims.
But there is also the question of the player apps, and they have a significant impact on sound quality. As an example, with an Antipodes Server/Player you can choose from player apps that are superior to the player apps used in DACs. Most of our customers wish to use Roon Server to manage their music and streaming services, with good reason. But this will generally mean you have to use the Roon player within the “Roon Ready” DAC. With an Antipodes, you can use the superior sounding Squeezelite or HQPlayer Embedded as the player app."