1 (edited by Chippy_boy 2019-01-17 18:31:32)

Topic: Noise when switched off??!!

I'm the proud owner of a new ADI-2 Dac and am really delighted with the SQ and feature set - I think it's fantastic!

However, I've noticed a small problem:  When the dac is powered on, there is barely any background noise coming from my speakers, but as soon as I power the dac off, I get a quiet buzzing coming from the speakers.  It's not loud, but it's audible at 8 feet and is a bit annoying since I tend to leave my power amps switched on.

If I unplug EVERYTHING from the dac - even the power - it makes no difference; the buzzing is still there.  It only goes away when I switch the dac on.

Incidentally, this did not occur with the old Benchmark Dac1-hdr the ADI replaces. So I am guessing there's nothing grossly wrong with the rest of my equipment or setup.  The power amps are connected by the same XLR's as previously.

Does anyone know what's happening here... and more importantly, how I can fix it?

Thanks folks

2 (edited by Curt962 2019-01-18 16:19:09)

Re: Noise when switched off??!!

Chippy,

I've pored over your Post several times, and indeed this dilemna is puzzling.

With EVERYTHING removed from the DAC, yet still the persistent noise....this seems to conclusively remove the DAC from Suspicion.

It would would not be unheard of for a Cable to have failed, and is now functioning as an Antenna, collecting noises from elsewhere in the room.   Perhaps it would be possible for you to obtain a different set for trial.   

Best Wishes for a Speedy Resolution.

Curt

Vintage 2018 ADI-2 DAC. "Classic AKM4490 Edition"
Cables:  Red, and White Ones.
Speakers:  Yes

3 (edited by cake2pai 2019-01-18 18:29:15)

Re: Noise when switched off??!!

I am the same as you.
dac - xlr - poweramp - speaker
Noise is heard when turned off.
I have dac and pro.
I tested these two devices and it was the same.

Re: Noise when switched off??!!

Guys...I firmly believe a Cabling issue is at fault.  A completely disconnected Unit cannot be blamed for noise can it?

Vintage 2018 ADI-2 DAC. "Classic AKM4490 Edition"
Cables:  Red, and White Ones.
Speakers:  Yes

Re: Noise when switched off??!!

Just tested this with my Pro (AE) and huge midfield active monitors and don't hear anything. Only super low noise when I put head directly next to the speaker, but that is there always even when Pro is disconnected and is not audible 2 feet far.

Note that my speakers are connected over AES3, but I believe I've never heard any buzzing even before they were connected to analog XLR.

6

Re: Noise when switched off??!!

It's quite clear that the ground that is delivered over the cables is bad or missing, as the ADI-2's housing is connected to said ground, and would prevent whatever noise that could be there, as it completely encloses the inner phase lines (XLR pins 2 and 3).

Regards
Matthias Carstens
RME

Re: Noise when switched off??!!

I have a quite similar (very minor) issue, but clearly induced by USB.

My system: PC -> USB -> ADI-2 DAC -> XLR -> Neumann KH 310

Only if the ADI-2 DAC is switched off and in standby-mode i can hear a crackling noise from the speakers sometimes. It depends on what i do with the PC: I can reproduce it if i start a video - every time i doubliclick a video and the player (KMPlayer) starts to play i hear a little bit of crackling for a few seconds. The noise fades after a few seconds but comes again from time to time. When i close the player and start the video again i hear the noise again. It may have something to do with the graphics card, but i´m not sure. I have a GTX 770 in my PC.

It´s on both channels, i can hear it when only one channel (XLR) is connected, and i even tried a different XLR-cable. I only have Cordial cables with Neutrik connectors. I didn´t experience it with two different DACs before, so i´m pretty sure it has something to do with the RME.

If the DAC is powered on or if i unplug the USB-cable, there is no noise at all.

It´s a very small issue because i almost always power off my speakers when i don´t use the DAC but from time to time i experience the noise.

8

Re: Noise when switched off??!!

You have a ground loop via USB between computer and active speakers. Cheap solution: remove pin 1 from one side of the XLR cables. Pro solution: Intona USB isolator.

Regards
Matthias Carstens
RME

9 (edited by Chippy_boy 2019-01-24 19:23:59)

Re: Noise when switched off??!!

Thanks guys for thinking about this and for your helpful comments.

Curt962 wrote:

Guys...I firmly believe a Cabling issue is at fault.  A completely disconnected Unit cannot be blamed for noise can it?

Well, if I remove the ADi-2 Dac from the XLR cables (attached to the amp) then the noise stops.  So I would say pretty definitely the noise IS caused by the Dac!


Curt962 wrote:

Chippy,

I've pored over your Post several times, and indeed this dilemna is puzzling.

With EVERYTHING removed from the DAC, yet still the persistent noise....this seems to conclusively remove the DAC from Suspicion.

It would would not be unheard of for a Cable to have failed, and is now functioning as an Antenna, collecting noises from elsewhere in the room.   Perhaps it would be possible for you to obtain a different set for trial.   

Best Wishes for a Speedy Resolution.

Curt

If it was just one channel, I'd agree it has to be the cable.  But it's both channels.  And as I say, it didn't occur with the Benchmark DAC. It is indeed a strange problem.  I have two mono power amps, and if I disconnect one of them completely, so all I have is DAC (with no inputs and no power cable attached) > XLR > Poweramp > Speaker, then I get noise at the speaker.  If I attach the power to the Dac and turn it on, the noise stops.

It's clearly picking up noise from somewhere, but I have no clue how.  And why does the noise stop when the Dac is switched on? 

cake2pai wrote:

I am the same as you.
dac - xlr - poweramp - speaker
Noise is heard when turned off.
I have dac and pro.
I tested these two devices and it was the same.

Which would seem like one hell of a coincidence.  I wonder what your setup and mine have in common, which others do not???

Re: Noise when switched off??!!

Well, a small update.  It's NOT the cables.

This weekend I made up myself a pair of XLR cables with Van Damme star quad, silver-plated, OFC cable and Neutrik connectors.

Didn't make a blind bit of difference :-(  Buzzing from speakers when ADi-2 Dac is switched off :-(

Re: Noise when switched off??!!

I have the same problem. The hum is quite loud and only occurs when the RME ADI-2 is turned off (red light) and connected. I've tried 2 different RCA cables connecting from RME ADi-2 to KEF LS50W active speakers. I also had the same problem connecting to a Pioneer A400X amplifier. As soon as I turn the RME ADI-2 on (ie; red light to white light) the hum disappears. The unit doesn't have to be connected to anything else for this to occur.

Re: Noise when switched off??!!

It's a bizarre problem (which I am still suffering with).  As it stands, I have to either leave my ADI-2 on all the time, or reach around the back of my power amps and switch them off every time i turn the ADI-2 off.  Neither "solution" is at all satisfactory and rather spoils an otherwise excellent product.

I would say it's nothing to do with the ADi-2, were it not for the fact that my Benchmark dac does not make the power amps hum like this, whether it's on or off.

Poweramps on, with no cables connected = no hum

Poweramps on, with ADi-2 connected via XLR (but powered off) = hum

Poweramps on, ADI-2 connected and switched on = no hum

The ADI-2 is picking up hum from somewhere, but only when switched off.  Another data point is that when you switch off the ADI-2, at first there is no hum and then slowly over a period of 4 or 5 seconds, a faint hum starts and then gets louder and louder.

It's like some capacitor is discharging, or a voltage somewhere is being allowed to float or something.  I don't know if that helps diagnose this?

Re: Noise when switched off??!!

Chippy,

Best to allow RME look at this with you.   In the interim however, WHERE is your ADI-2 DAC PSU located???    Let's pull the IEC cord out of the PSU, and see what happens.     

Curt

Vintage 2018 ADI-2 DAC. "Classic AKM4490 Edition"
Cables:  Red, and White Ones.
Speakers:  Yes

Re: Noise when switched off??!!

Curt962 wrote:

Chippy,

Best to allow RME look at this with you.   In the interim however, WHERE is your ADI-2 DAC PSU located???    Let's pull the IEC cord out of the PSU, and see what happens.     

Curt

Already tried that. (See above for all the tests done).

The ADI-2 causes the same hum even when it is disconnected from its own PSU and has no inputs connected either!

I haven't tried moving the ADI-2 to a different location however. I will try that. At the moment it is on an open shelf in its own. However, above it is a Sky box. Maybe there's some RF noise coming from that?

Personally I have a suspicion this is something to do with floating voltages which get held up, or held down when the ADI-2 is on, but not when it's off. But I really don't know.

Re: Noise when switched off??!!

Chippy.  (Is that in reference to a REAL UK Chippy?   Oh Wow!!!   Such an amazing Treat!)

Take this mysterious matter to RME directly.   I suspect an EMI source in your Room.  An "OFF" ADI-2 DAC is not capable of "producing" anything.   Lest we forget... Light Dimmers are wonderful sources of such BS noises when induced into cabling, etc.

Take it straight to RME Chippy.

Curt

Vintage 2018 ADI-2 DAC. "Classic AKM4490 Edition"
Cables:  Red, and White Ones.
Speakers:  Yes

16

Re: Noise when switched off??!!

Well, he is at RME. But I failed to reproduce this effect (as most others) and have no perfect explanation. It's the usual pity - if he would be near us I would just drive there, examine it, most probably find the reason and solution in minutes - case closed and a nice entry for the FAQ. Unfortunately the world is more complicated...

Regards
Matthias Carstens
RME

Re: Noise when switched off??!!

Chippy.  I dragged the Boss (MC) into a matter that we should be able to resolve ourselves with some old-school troubleshooting.

In your noise condition...let's move Wires.  Lets Rotate the DAC/PSU 90 deg, and listen for changes. 

There is most certainly an Electrical Noise generator in your room.    As I said before, Dimmer Switches are notorious for this. Other devices could be equally culpable.

Something is F'd in your set up.   Let's find it.

Curt

Vintage 2018 ADI-2 DAC. "Classic AKM4490 Edition"
Cables:  Red, and White Ones.
Speakers:  Yes

18 (edited by KSTR 2019-09-11 08:38:37)

Re: Noise when switched off??!!

Chippy_boy wrote:

If I unplug EVERYTHING from the dac - even the power - it makes no difference; the buzzing is still there.  It only goes away when I switch the dac on.

The ADI-2 is picking up hum from somewhere, but only when switched off.  Another data point is that when you switch off the ADI-2, at first there is no hum and then slowly over a period of 4 or 5 seconds, a faint hum starts and then gets louder and louder.

To me this indicates an phenomen related with the output mute transistors. Those short the output lines (+ and -) to GND during startup and shutdown, but on shutdown only as long as there is some power available sitting in the reservoir caps for the supply relevant for the mute circuit.

Once the mute transistors go open again, each line gets re-connected to the circuit again, but most probably these nets do *not* have neither the same source impedance nor the same noise pickup characteristics in the power-off state, and that's why a sensitive receiver circuit may see some hum/buzz noise difference signal now. I would suspect, though,  the noise level should be really low as the RME is cased in a conductive metal box which shields the lines properly.

Can you increase the send level on the Adi and reduce gain at the power amp /active speakers?
This would help the issue.
If you don't have gain knob/switch at the receiver, a passive attenuator could be build (4 resistors) that would be inserted right before the amp input. Both the attenuation and the resistive paths to GND would greatly reduce the hum/buzz.

19 (edited by Rodmanch 2019-09-12 09:39:09)

Re: Noise when switched off??!!

An interesting topic. I myself checked out of curiosity how it looks in my system. And it looks like this.

When the DAC is OFF, the noise is at the level of the monitor's own noise, when I turn it ON the noise is a bit higher (maybe 1dB or less). To hear the difference I had to increase the sensitivity of the monitors has a max and put the ear to the tweeter.

The system and connections look like this:
ADI DAC +19 dBu > 4.5m XLR (Mogami 2549) to subwoofer (Adam SUB 12) > 2.5m XLR (Mogami 2549) to monitors (Neumann KH 310A)
No difference is if the monitors have ground CONNECT or LIFT.

So in my case during normal use, when the monitors are set to 100dB SPL at 0dBu, everything works perfectly well and I can't hear any difference between ON or OFF.

Best

Re: Noise when switched off??!!

Just got an ADI-2 DAC a few weeks ago and decided to check this out as well. About 3 seconds after power off I can hear a nasty sounding buzz through my headphones, with my volume higher than I normally set it. So it's definitely volume dependant. Some may hear it at their normal volume, others will need to turn it up.

For me it doesn't matter since I always turn off my amp. Plus I don't hear it at normal volume.

Re: Noise when switched off??!!

I have this issue too, at first I thought it was a faulty with my expensive balanced amplifier but I was relieved when I saw this thread. The only solution I came up with is to power the ADI-2 DAC then the amplifier and get the audio signal to run through the ADI-2 DAC as soon as possible! It is like the blood circulation through the human body and such or my amplifier is very badly designed and no match for the ADI-2 DAC!

22

Re: Noise when switched off??!!

Markx, do you use the DAC's XLR outputs into balanced XLR inputs?

Regards
Matthias Carstens
RME

Re: Noise when switched off??!!

MC wrote:

Markx, do you use the DAC's XLR outputs into balanced XLR inputs?

Yes, The DACS XLR balanced outputs into the the XLR balanced inputs of the Auralic Taurus MKII balanced headphones amplifier, I have two ADI-2 DAC units and both of them exhibit the same behavior on standby mode but when switched on the distortion disappears and I get a black background. I tried to forgo the amplifier and use the single ended output of ADI-2 DAC alone and in reality there was nothing to complain about the sound is perfect and saving space is another benefit too but I can’t sense the feelings, emotions and passions that I get with the Auralic. Despite this issue I am truly happy with both units and the sound I get.

24

Re: Noise when switched off??!!

Is the email adress that you entered here vaild?

Regards
Matthias Carstens
RME

Re: Noise when switched off??!!

Hi,

Just received my AID-2 DAC, and same problem.
Ok when powered on (and sound fantastics!) but loud hum noise when it's in standby.

The only input source I have is optical toslink, and use fully balanced amp (ncore) and XLR cable.
I'll make further tests today. (remove toslink, ...)
Thanks

Re: Noise when switched off??!!

Hi, I just wanted to add that also my unit suffers of the same issue.
I tried it with both balanced and unbalanced connections, with 2 different amplifiers and with and without a preamp before the amp.
In all the above configuration, 3/4 seconds after the ADI-2 DAC is turned off there a moderately loud hum going through the speakers. My model is the FS version with the AKM4490 chip.

Re: Noise when switched off??!!

Hi there, I have absolutely the same unpleasant problem. When my RME ADI2 DAC FS Firmware Version 0.32 is switched OFF and amplifier is ON, there is a crackling and hum from the speakers. Tested this with Hegel H160, T+A PA3000HV, Audionet MAX II monoblocks, all the same problem. Also, tested XLR and RCA outputs of RME, same problem all the time. I really think the people from RME have to pay attention to this problem, it clearly comes from the unit itself, not from cables, etc. The logic is very simple, because when I replace RME ADI2 DAC FS with other dac from different brand and the rest of my system is the same, the problem dissapears completely. RME support team, how you can explain this?

28

Re: Noise when switched off??!!

The DAC does not have a ground connection. Using RCA you should be able to remove the noise by unplgging the unit's power supply, or by grounding the unit. Note that we expect the power amp to be shut down when the DAC is turned off. That can be easily done automatically with Master/Slave power strips.

Regards
Matthias Carstens
RME

Re: Noise when switched off??!!

Had that problem with a pair of Genelec 1029a driven by an ADI-2 DAC  via a KRK 10S Subwoofer. No noise at all without the subwoofer. Problem solved by using the groundlift switch on the KRK. Issue with KRK, not RME.

I have since replaced that setup with Neumann KH750, KH120. Dead silent, DAC on or off.