Sony HAP-Z1ES static?


I've been interested in moving to a music server for the last couple years for convenience (mostly for the family: while I like playing CDs, others in my family are used to having instant access to their entire library). After doing a little research, I landed on the Sony HAP-Z1ES player, and purchased one used last year. I swapped out the stock drive with a 2TB SSD, and ported over my music library. I found that I really appreciate the convenience of the unit, more so than I thought I would. 

I do have one issue with it. I recently added a USB input to my MBL 1611F DAC, and sent the output from the Sony to the MBL via the USB connection. The sound is much improved over the Sony's analog outputs, but...

When I play music through the USB output, I get a little click or popping noise, which sounds like static, every 2:25. This happens with almost every song. If the first song is 6 minutes long, I will hear the static noise at 2:25 and again at 4:50. I will hear it again at 1:15 of the next song, as that is 2:25 from the previous pop. If the song is paused, or I skip to a different track, the counter resets.

I've tried switching USB cables, which had no effect. I've tried switching back to the analog output from the Sony, which doesn't exhibit this issue. I've hooked up my laptop using the same cables to the same DAC, and don't hear the same issue. My Sony has the latest firmware installed. 

I've contacted Sony support about this two weeks ago, but haven't heard back. Has anyone else encountered this issue? 
mistercrash
Interesting, I've noticed something similar. Does it sound like "interference"? I'll notice it once in a while with no pattern.  Just a guess but I think it's something with the wifi connection amplifying a noisy internal computer operation (disk read, etc.).  I don't notice this when it's wired directly, only when using the wifi connection.
Hmm...I hadn't thought of that. I'll try checking it out with the Wi-Fi switched off, and report back.
Unfortunately, turning off the Wi-Fi did not resolve the issue. I've also tried changing just about every system setting to no avail.