This is of course helpful, but for me there are still a couple of unanswered questions. When my Yggy was in the chain and hooked up to the Eitr, it was clicking both during playback and in idle mode, when nothing was playing. There were even times when the clicking in idle mode seemed to be responding to the electrical impulses generated by other unrelated non-audio appliances in the same room as this system, but I lack the technical expertise to understand or explain how the Yggy/Eitr combo, or better yet, the muting relay in the Yggy, could be responding in this way to electrical stimuli or impulses around the room when playback was not active at all..
Now let me add the following for the sake of more transparency.
1. before the Eitr arrived, I was using the Audiophilleo 2 with Purepower as the USB to SPDIF converter hooked up to the Yggy, and I don't remember ever experiencing any clicking with that configuration.
2. The primary source has been successively a macmini, a microrendu, and an ultrarendu (with the latter 2 being powered by an Uptone LPS-1). Playback was smooth (and operated without any clicking) with the mac mini and microrendu in that configuration, but the ultrarendu did not fit well into that picture because of problems related to the distribution of voltage and power draw, that it introduced between the LPS-1 and the requirements of the Audiophilleo 2 with Purepower. Suffice it to say (without getting into more technical specifications) that replacing the audiophilleo 2 with Purepower with the Eitr (which has its own independent power supply, unlike the A2 w/PP) solved that problem, except that the Eitr also came with the problem of making the Yggy click, as described above...
With all that said, is the clicking of the Yggy, while connected to the Eitr, exclusively linked with the problem of muting relay as mentioned in the FAQ notes...? The part I do not get about that explanation is why the Yggy should click in that configuration even when nothing is playing... i.e. even when it is not supposed to be processing any audio signals...