Topic: RME Adi-2 DAC - Low level noises

Hi everyone!

I recently grabbed a new ADi-2 dac to "replace" my Adi-2 Pro (non fs version), since I didn't have any use for the A/D section and wanted to take advantage of the IEM output of the adi-2 dac.
However, to my surprise, I am getting a lot of low level noises and a constant pulsating sound like "tak tak" coming out of it.
I thought it could be a ground loop so I unplugged all the devices connected to the same grounded power strip and narrowed it down to the wifi router. If I unplug it, the noises are gone. If I plug it again, the noises start only when the router starts transmitting.
The funny thing is that with the Adi-2 Pro, plugged to the same computer and using the same cables in the exact same location, I was not getting any interferences. If I touch the ADi-2 dac with my hand, the noise seems to decrease.
I also tried a cheap (but very nice) dac/amp that I use with my PS4, again using the same cables, etc., and the headphone output is completely noise free...
So I am wondering if there might be some shielding issues with my unit.

Any input on this would be highly appreciated!

Thanks in advance

2 (edited by Viennacalling 2018-12-03 18:40:08)

Re: RME Adi-2 DAC - Low level noises

Maybe you can record the noise and post it here with a short video - might help to solve the problem.

Here is an example of showing a bug from a different  company with a little video: https://youtu.be/Bf38cKJ6NBc

Re: RME Adi-2 DAC - Low level noises

Thanks for the suggestion!
However, the noise is mostly noticeable in the IEM output, so I don't really know how to record it.
I only use the dac for music listening. I don't have any recording equipment.

4

Re: RME Adi-2 DAC - Low level noises

That is indeed a ground problem. You need to connect the DAC to a good earth/ground potential, as it happens when you connect it other, properly earthed devices. The Pro can also show this issue, but as you might have realized from your own statement 'only on the IEM output' it won't be as obvious over there.

If your power strip (and the rest of the power net) does provide grounding then it might be enough to plug the router or the ADI's power plug or both reversed. Experiment a bit.

Regards
Matthias Carstens
RME

Re: RME Adi-2 DAC - Low level noises

Hi again,

I thought that I had fixed this issue, but I was wrong.
I am still getting lots of little distortions and pulsating noise in the IEM output when using my earphones...
I have plugged both the router and the DAC in different power outlets, rooms, grounded power strips, and as soon as I move the DAC closer to the router, I start getting these noises.
I also plugged a cheap DAC/headphone amp using the Adi-2 DAC power supply, and even if the DAC touches the router antennas, I get zero noise in my earphones. All this makes me believe that there might be an issue with my unit.
I've had a lot of DACs in my life and I have never experienced something like this.

This is driving me nuts, really. Would it possible to send it to check up somewhere?

Thanks

6

Re: RME Adi-2 DAC - Low level noises

> different power outlets, rooms, grounded power strips

...don't qualify as grounding the ADI. The ADI's power supply is ground-free, so wherever you plug it in there is no ground connection to the ADI's housing.

> If I touch the ADi-2 dac with my hand, the noise seems to decrease.

The ADI is connected via USB to your computer which should have a three prong power connector and provide ground to the ADI. Obviously that doesn't work, or ground in your power outlet is either missing or contaminated.

For a valid test try to connect the ADI to something that is guaranteed to have ground, like radiators or water lines.

BTW, is the noise also there when you remove the USB connection?

Regards
Matthias Carstens
RME

7 (edited by sindri1980 2019-01-22 03:31:32)

Re: RME Adi-2 DAC - Low level noises

Actually, when I touch it, the noise increases. Depends on where I touch: right side, increases. Left side, decreases.
I am actually connecting it through an Ifi iUSB3.0 with an independent power supply for the USB cable.
But it doesn't matter, connected to my PC with a standard USB cable produces the same noises.
Connected just to the wall power outlet in another room, no pc nor USB, it gets the same noises if I put the router close.
And the fact that doing the same thing with another dac/amp doesn't produce any noise at all makes me wonder if my unit is defective.

Re: RME Adi-2 DAC - Low level noises

You might give this a try (see link below).  Only requires very, very basic skill.  It completely solved a similar noise/grounding issue using an UltraRendu streamer powered by an Uptone LPS-2 power supply, with the UltraRendu connected by USB to my ADI-2 DAC FS.


https://audiophilestyle.com/forums/topi … grounding/

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Re: RME Adi-2 DAC - Low level noises

@sindri1980: I don't think so. The 'other' DAC/amp doesn't have a comparable IEM output. Super low noise and 0 Ohm output impedance might produce a different behaviour under critical EMI/RF conditions.

I don't know why you not simply try what I suggest. As breaking the ground connection to your computer might help I wonder if you checked the Isoground switch of the iUSB3.0. It should help, but I have no personal experience with that unit 

You are welcome to send your unit in for a check. But in this special case I fear they will test it, hear no noise, and return it...

@rpgroman: that's another way that might help, thanks. Please note that it requires the earth at the power output to be good. Here I am not sure this is the case. Also this case is a bit different as it seems to be related to the router's RF signal, and not any leakage current.

Regards
Matthias Carstens
RME

Re: RME Adi-2 DAC - Low level noises

Thanks @rpgroman for the suggestion. I'll take a look into it.
@MC, thanks a lot for your input too. Changing the Isoground setting of the iUSB3.0 didn't make a difference.
Could you please elaborate your suggestion a little bit? Connecting the DAC to a radiator or water line, you said.

11

Re: RME Adi-2 DAC - Low level noises

Take a simple wire and connect a blank part of a cold water pipe or unpainted radiator with for example the outer metall part of the ADI's RCA jack. If you touch that ground while having your In-Ears in use the interference might increase. But grounding the unit there should decrease it.

Regards
Matthias Carstens
RME

Re: RME Adi-2 DAC - Low level noises

Hi,

I just tried your wire suggestion. Unfortunately, it didn't make any difference at all. The same type and amount of interference noise were present.
I also tried my in-ears in the Phones output using an adapter and I don't notice any noise at all. Only the IEM output seems to be picking these interferences from the router.
I happen to have a wifi extender in the living room (not where the DAC is plugged currently), so i connected it in the same power strip and, again, I get the same type of noise.
I am not particularly savvy with all this electrical stuff, so any further input would be highly appreciated.
Is there any chance that the IEM output of my unit is not properly shielded? Or is it definitely an issue with my setup?

Thanks again for the help.

13

Re: RME Adi-2 DAC - Low level noises

What happens if you put your two hands around the IEM cable near the socket? It seems to me that the RF stuff gets into the IEM output stage via the IEM cable itself, working as antenna.

This is a strange issue.  I also can't imagine any way that the ADI is defective so that this issue is generated.

Regards
Matthias Carstens
RME

14 (edited by sindri1980 2019-01-27 22:29:09)

Re: RME Adi-2 DAC - Low level noises

You mean without the wire thing, right?
If I put my two hands around the IEM, the interferences are reduced actually...
And also, if I touch the in-ear plug when plugged to the IEM output, the noise goes away, so you might be onto something there.
If there is any chance that there might be an issue with the unit, I would prefer to send it for a check up to have some peace of mind.

Re: RME Adi-2 DAC - Low level noises

Hi Matthias,

I hope I'm not being super annoying with this (I may be). Today I tested the dac at a friend's house and when close to the router, it picks the exact same noises only in the iem output.
I wonder if there might be a shielding issue in that output or something.
Again, would it be possible to send it for a check up?

Thanks

Re: RME Adi-2 DAC - Low level noises

I thought I'd tack on to this thread as I had an almost identical issue when using IEM's and I thought I'd solved it by replacing the power supply - the interference seemed to vary depending on where the unit and power supply and wires were placed, so I moved the unit and swapped the SMPS for a more shielded unit (check the "Just a few questions from a beginner thread). However, I had it all wrong.

The problem wasn't the power supply, or the placement of it or the unit. The problem was the cable I was using on my IEM's. When I moved the unit and changed the PSU the problem went away but what I'd failed to take into account was that I'd also had to add a short headphone cable extension to reach my seat. Earlier today I plugged my IEM's straight in and the interference was back again. As I went to unplug them I noticed the noise went away when I touched the metal 3.5mm plug housing. Touching other parts of the unit or grounding it to a pipe make no difference, it's actually the cable itself.

The differences between the stock cable and the aftermarket cable are really quite minimal. The aftermarket is thicker and nicer to use but there's certainly no difference in overall sound quality. However, it has quite a large straight steel jack rather than a moulded 90° plastic 3.5mm. Perhaps there's a difference in the wiring too, I don't know. I have three of these aftermarket cables and they all behave the same.

So now the problem is solved, I can either use a short extension (mine is just a Sony extension with plastic connectors I got with another pair of headphones) or just swap my IEM's cables back to the originals. If you're still hearing interference try adding an extension or swapping out your IEM's cable.

It's not a problem I've ever run into before. In retrospect I think when I was moving the PSU, wires and the DAC around I was also moving my head around - the aftermarket headphone cable seems to work as an antenna unless you ground the plug with your finger. There you go anyhow, if you're getting interference out of the IEM output then it's worth trying different headphone cables if you can, or an extension if you can't.

Re: RME Adi-2 DAC - Low level noises

Hi @JustPoo!

Sorry for the late reply.
I think you got a point there. I tried a different cable with a plastic connector and the noise is gone or at least severely reduced.
Thanks for the input!

Re: RME Adi-2 DAC - Low level noises

I'm glad it helped you, Sindri, it drove me nuts trying to nail down exactly what the cause of the interference was. Actually I still don't really know exactly what the cause of the problem is, only how to address it!.

Why certain IEM cables pick up interference and need grounding is beyond me, but it's a bit frustrating having to swap out cables when you go from another device to the RME. I'd just leave an extension plugged in but then the unit doesn't automatically recognise and switch over to phones settings when you plug into the full sized jack. Barring automatic switching, I'd like a setting to manually switch not just between line out and phones, but line out, phones and IEM mode - then I could leave short extensions plugged in and not only cure the interference issue, but also reduce wear on the sockets.

Just another gentle nudge smile - I'd still love to able to prod the volume knob for mute, it just makes sense to me for a volume knob. Keep the long press for switching between phones and line-out (and IEM!), it's handy if you use it, but a quick press for mute would be useful. It obviously can't mute it in all menus, but when the unit is sat on one of the main screens it's the intuitive option. Or maybe either the treble button or bass button could be assigned to mute rather than them doing basically the same thing? It seems wasteful to use one of the four assignable keys to mute when there's three other buttons available, especially as when you do that the mute function is doubled up on the remote because the unit and remote's custom keys are linked. They could do with being seperate, with a few more options too (cycle custom EQ, crossfeed, balance left/right, bass/treble - maybe cycle/up/down/left/right with volume - just some things that are handier when you're sat back and need to tweak. It's pretty much the desktop king as it is, but RME don't strike me as the kind of company to say "that's good enough". I'm hoping the squeaky wheel will get the grease when it comes to the next firmware update big_smile

19

Re: RME Adi-2 DAC - Low level noises

sindri1980 wrote:

Hi @JustPoo!
I think you got a point there. I tried a different cable with a plastic connector and the noise is gone or at least severely reduced.

May the noise is some oscillation in the higher frequency range (MHz) and without proper measurements ... it's fishing into the dark

20

Re: RME Adi-2 DAC - Low level noises

Maybe you are oscillating here - the ADI isn't.

Regards
Matthias Carstens
RME