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
Well it was worth a try. USB connections can be a bit noisy, you could try an isolator like the Intona. Not an inexpensive experiment but being you only hear it on the USB connection it might help. I use one because of a ground loop I had with an old computer used as a digital server before the HAP-Z.  
A couple updates:

1. I pulled out the SSD drive I had installed and replaced it with the original HDD. Same result here: an audible static noise every 2:25 when using the USB output, which wasn't there with the analog out. 

2. I found a good deal on a Bel Canto Light Link, which converts USB to an ST optical signal, and plugged that into the ST input of my DAC. That did the trick: sound quality was as good as before, but the crackling was gone. I went back and forth a few times, switching between the USB straight to the DAC and the USB to the Light Link to the DAC, and confirmed that the issue was still there with the direct USB connection but gone with the Light Link.

So, it seems my issue was probably due to some electrical mismatch between the Sony's USB output and the MBL's USB input. Once the USB was converted to an optical signal, it went away. 
That's great, it seems the USB connection was the problem.  I think from a result point of view that's similar to using an isolator - basically removing the direct USB connection.  Glad to hear you figured it out.  When I had a ground loop problem it drove me nuts trying every combination possible until I broke down and got the Intona.