Help - Mystery Hum that starts at my Streamer

Hi,

My set up is:

Auralic Aries G1 Streamer w/Hoer Upgraded power supply

MHDT Pagoda Balanced DAC 

Zesto Leto Pre 

Krell 300XD Duo 

Alta Audio Alec’s 

REL Ti9 Sun 

Furman Elite 20 Ultra Linear Power Conditioner 

I have a low frequency hum that comes out of just my left speaker and just the woofer.  Through trial and error, conversations with several audio professionals have identified my streamer is the source.  Swapped all cables, power chords, outlets, plugged into the Furman, bypassing.  Have swapped pre’s and also run from the DAC to the amp directly, used different outputs from the streamer, used Wi-Fi and Ethernet connections on the streamer.  As soon as I unhook the streamer, hum goes away.  Hum’s volume doesn’t change when I lower or raise the volume.  It disappears when I insert my Krell Pre into the equation, but is present with all other Pre’s I’ve tried.  
 

I’m at a loss as to what would cause the hum. Any ideas? I have also contacted Auralic directly but haven’t heard back yet.  I’m guessing Aurilac will point to the power supply, aftermarket.  I’ve been lucky enough to have a couple audio professionals walk through the trouble shooting, possible causes.  Neither thinks it’s the power supply but they are at a loss as to what the root cause is.  
 

Any insights or help would be awesome.