1 Topic by cskippy (edited by cskippy 2018-04-16 20:40:16)

  • Registered: 2018-04-16
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Topic: ADI-2 DAC grounding noise with Andromeda

Okay, this is crazy!

I just tested this in another room and the results are very surprising. 

With no inputs or outputs connected to ADI-2 except Andro, I can hear a very low buzzing sound like when you touch an active RCA cable that goes to your amp. 

What's REALLY weird, is that it changes depending on what I am touching, including the floor!  If I lift my feet off the ground (tile), the hum is basically inaudible.  If I place my feet squarely on the ground the hum increases.  If I touch my hand to various other components connected on the same circuit the hum can be either slightly louder of very loud. 

I know that you can use cheater plugs to lift the ground on some devices and this can fix the above problem but ADI-2 doesn't have a ground connection. 

UPDATE:  I was trying to use this as an AIO for convenience, but I decided to connect another amp (with a 3 prong power cable) using RCA and Voila! no more hum.  I am still using the built in IEM output.

It seems like ADI-2 needs a better connection to ground to alleviate hum with sensitive speakers/IEMs. 

I contemplated not posting this, as reading the beginning, it sounds ridiculous, but I hope others can learn from my findings.

2 Reply by MC

  • MC
  • MC
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Re: ADI-2 DAC grounding noise with Andromeda

Well, the 3 prong plug is the opposite of what you needed - ground. Your setup doesn't have ground and got insufficient ground over your body only. But thanks for posting, it shows how bad power cabling in some homes can be.

Regards
Matthias Carstens
RME

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  • Doco
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Re: ADI-2 DAC grounding noise with Andromeda

Another user also had this issue here: https://www.audiosciencereview.com/foru … 82/page-13

The power cabling was noted to be of poor quality: "I just checked which one of the contacts here is hot and ground. Turns out both are hot. The "ground" contact is just less hot than the other one. This is a really old building with old electrical installations. All the outlets are 2 pole instead of 3 pole."

But in this case the hum could also be removed by establishing an electrical connection to another grounded device. So while it seems the ADI-2 DAC does not like bad cabling at all, it can be easily remedied.

4 Reply by MC

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Re: ADI-2 DAC grounding noise with Andromeda

I just wonder where the other device got its ground. This brings up memories from long ago, where one had to connect HiFi's ground to a radiator, water line or such to get a real ground. In the above example the grounding prevents the current to flow over the user's body, so the IEMs no longer 'hum'.

Regards
Matthias Carstens
RME

MC's Website

5 Reply by hhrvoje (edited by hhrvoje 2019-05-30 14:21:03)

  • Registered: 2019-05-30
  • Posts: 25

Re: ADI-2 DAC grounding noise with Andromeda

I had same problem with hum (noise from PC leaking into the speakers, when CPU is doing something or I move the mouse. Even when RME is unplugged from the wall! Wasn't happening with several DACs i owned before)
Purchased iFi iDefender USB 3.0 Ground Loop Eliminator and RME is dead quiet now! Finally can enjoy late night music:)
Hope will help to someone googling this issue...

~~ sound sommelier ~~