DAC's and the Two Ground Loop Types

Quick topic.  So everyone knows, there are 2 possible types of ground loops a DAC can be subject to.  Still. 

The first is the normal, audible hum caused by a ground loop.  This can happen when the source is on a different AC branch circuit for instance. It's exactly like every other ground loop problem most of us are familiar with.  Just like them, this requires metal to metal signal transmission.  In my mind it's very disappointing that this even happens anymore since USB isolator chips, and coax S/PDIF transformers are plentiful and cheap.  My Mytek Brooklyn absolutely shows this problem when I run a long USB cable to my PC, something I only do for audio testing.  Fixed it by switching to a laptop.

The other type of ground loop issue is in the digital domain and evidences itself as excess jitter sidebands.  I have seen measurements for this, I think in Stereophile.  Again, same exact cause but we don't hear it the same way.  There's no audible humm.

Even a cheap, hospital grade USB isolator would fix either issue, but in the case of the Mytek, these won't work.  I haevn't tried an iFi with it's own additional power supply though. 

If you have Ethernet you should not have any ground loop at all.  Because Ethernet is meant for long runs, with equipment at various ground potentials to begin with, it is galvanically isolated at each end.  However! A 4kV hospital grade isolator is inexpensive and often used for lightning protection.  If you try one and it helps youyr audio quality do let me know.


Here we go again a bunch of rambling unsupported claims with poor punctuations.

@erik_squires Hi Eric, I bought these from Amazon a while back; they are not manufactured for audio, more an installation product to protect against surges/lightning strikes. Made a very subtle difference in clarity for me. There is a review out there somewhere, from Germany I think it was, from someone who stumbled across these and tried them in their hifi system. There is some kind of isolation built in to them which may be what’s giving beneficial results.

Worth a punt at 20 odd quid (£)

DeLOCK 62619 - cable interface/gender adapters (RJ-45, RJ-45, Female/Female, Grey, Polybag) https://amzn.eu/4WEPwOi


That’s kind of how I stumbled across them, I was reading some technical articles about surge protection for Ethernet. The article discussed the difference between protection that isolates vs. those that shunt to ground and it made the point that generally speaking the isolators performed better in real world surge events.

In theory, Ethernet is isolated already, but I can see how extra isolation could reduce the noise transmission.  The devices can be really cheap, as you point out.