Help - Mystery Hum that starts at my Streamer


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.  



Cleeds - thanks for the quick response.  I noticed the hum once I swapped out the Krell Pre for the Leto.  That’s when I tried my Anthem HT receiver as a pre and going direct from my DAC.  Only combo that elevates the him is with the Krell Pre in the mix.  I should mention I swapped out all the tubes in the chain - DAC and Leto to ensure a faulty or noisy tube wasn’t the culprit. 

Weird... if you have a USB source, disconnect it.  I have seen those cause audible as well as jitter hum.  My own term for worse jitter due to a ground loop.

Usually you don't need to use an Ethernet isolator, except if there is a shield connected at both ends.  The hum present from a USB or Ethernet ground loop is usually present even without music, so unplugging the Ethernet cable should help you diagnose it as a potential source.

I use one of these to isolate my Ethernet and to improve the surge protection:



PS - Before you ask, recent studies on internal Ethernet surges suggest against grounding the cables but that isolating the cables minimizes surge damage. Grounding a surge in an Ethernet cable gives current a place to go, which is bad when it runs through tiny wires in the wall.  Better to isolate the Ethernet and let a surge find a path to ground via a power supply.

Thanks for your comments Erik!  I have the Ever Star in the chain and I have unplugged the Ethernet cable, hum is still present.  Had forgotten I had tried that during my process of elimination.

Maybe it is the upgraded power supply, unit has an internal supply and the upgrade is internal.  Only variable I can think of that I haven’t ruled out.  

Happy NewYear.