• Registered: 2020-12-26
  • Posts: 3

Topic: Adi dac 2 fs high frequency noise from unit

Hi there,

Received one of these for Christmas and absolutely love it. However, I've noticed there's a high frequency noise coming from the unit upon started up, after the clicking sequence has finished. Not sure if this is an issue and it's only really noticeable if I put my ear close to the unit. Connecting the unit via usb to my macbook pro seems to make the noise more high pitched but it's there regardless of whether connected to usb or not.

I've seen other threads discussing something similar but those did not directly apply to my situation. Is it a ground loop?

Any help is welcome.

Thanks,

Rob

  • Registered: 2019-12-15
  • Posts: 38

Re: Adi dac 2 fs high frequency noise from unit

never heard such a thing in mine. I can't stand those I would had detected them.. unless >16khz

  • Registered: 2020-12-26
  • Posts: 3

Re: Adi dac 2 fs high frequency noise from unit

Thanks for your response. Yeh, I find noises like this frustrating, although in reality it's undetectable when using headphones and will be when playing music via RCA out too. Just trying to understand if there's a fault with the unit.

4 Reply by ag (edited by ag 2021-01-04 21:49:13)

  • ag
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Re: Adi dac 2 fs high frequency noise from unit

Hi Rob,

I got my unit in November (absolutely love it) and similarly noticed a high-pitched whine after startup – faint but audible when the unit is plugged into AC and the relays have finished switching on. Thought it might be some onboard voltage regulation noise but after some troubleshooting I figured out it’s directly related to the screen.

I can change the pitch and volume of the whine with the LCD Brightness setting. At 100% brightness the noise is all but gone. The dimmer I set the screen, the more it whines. Figures, I prefer my screen brightness at 40%.

Importantly, it seems to be well isolated from the output signal. There’s no hint of any noise coming through the phones output, paired with my LCD-X.

My advice: set the screen brightness where you want it, put on your headphones and enjoy the music. Hope this helps!

Andy

  • Registered: 2017-02-18
  • Posts: 176

Re: Adi dac 2 fs high frequency noise from unit

Is it from the power adapter or from the unit
Can you make a video?

Adi-2 Pro, Adi-2 Dac Fs
  • From: Germany
  • Registered: 2007-04-10
  • Posts: 9,751

Re: Adi dac 2 fs high frequency noise from unit

Please return the unit as a warranty case... Not sure what this is, but of course it shouldn't happen.

Regards
Daniel Fuchs
RME

Regards
Daniel Fuchs
RME

RME Support's Website

7 Reply by ag

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Re: Adi dac 2 fs high frequency noise from unit

It’s coil whine – a more audible hissing sound the more the screen is dimmed. Happens on all sorts of boards with coils. Common on some monitors. Here’s what mine sounds like: https://imgur.com/a/3RMSau7 (you may need to turn up the volume to hear it)

8 Reply by MC

  • MC
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  • Registered: 2007-04-06
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Re: Adi dac 2 fs high frequency noise from unit

I cannot hear 'coil whine' in your recording. Background noise, movement, clicks...The spectrum shows a frequency varying a bit between 12.5 kHz and 14 kHz. If you are able to hear this within all that noise then the recording does not represent the real situation, or your ears are too sensitive for higher frequencies. Returning the unit might just get you another one where you hear the same.

Regards
Matthias Carstens
RME

MC's Website

9 Reply by bejoro (edited by bejoro 2021-01-09 11:15:20)

  • bejoro
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  • Registered: 2017-03-16
  • Posts: 299

Re: Adi dac 2 fs high frequency noise from unit

Maybe PWM noise from the display if dimmed?

bejoro's Website

10 Reply by KaiS (edited by KaiS 2021-01-06 19:28:58)

  • KaiS
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  • Registered: 2020-02-05
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Re: Adi dac 2 fs high frequency noise from unit

On my ADI-2 Pro I can measure a 12.2 kHz signal at ~ 6 dBSPL and a noise spectrum of equal level above 12 kHz, close to the right side opening grid.

This is 10 dB below the threshold of hearing.
The signal is independent of LCD Brightness setting.

From 1/2 m distance the signal is not measurable (measurement limit ~ -10 dBSPL).

Thus, by implication means, if you hear something in a distance from ADI-2 DAC there is a chance that your specimen has unusual high mechanical noise.


Measurement with a calibrated system on iOS AudioTools.

KaiS's Website

11 Reply by ag

  • ag
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Re: Adi dac 2 fs high frequency noise from unit

Apologies for the bad recording. “Coil whine” may be the wrong description. PWM noise from the display might be more accurate – on mine it can only be heard if your ear is within ~6 inches of the unit, and goes away when the screen is at full brightness. I was just trying to illustrate what I thought the OP, Rob, might have been hearing. Don’t think anything is wrong with my unit. Hope this helps!

Best, Andy

  • Registered: 2020-12-26
  • Posts: 3

Re: Adi dac 2 fs high frequency noise from unit

Sorry guys, forgot to check back on the thread.

Thanks for your input Andy, I can confirm adjusting the screen brightness on my unit does the same as on yours. Higher brightness is better, lower worse. Helpful to know it's not specific to my unit, so thanks again.

Judging by Matthias's response changing the unit won't necessarily change anything, so it is what it is.

Thanks again for everyone's input.