• Registered: 2021-02-12
  • Posts: 4

Topic: White noise issue only with line output 4

Hey all,

Brand new to the forum, been using RME products for almost 10 years. Wondering if anyone has any advice for me on this: today I tried using line output 4 on my Fireface 400, and when I first plug it into a speaker it is dead silent like all the other outputs, but when I play any type of audio, a loud white noise hiss plays through the speaker connected to line output 4 only. If I turn that same speaker off and back on, the noise goes away completely until I pass any audio through it again, and then the white noise comes back. Even after I stop playing audio and mute channel 4 in Totalmix, the white noise continues. It only goes away when I turn the speaker off. It does play audio, there's just alot of white noise mixed in only when using output channel 4.

I've tested all other line outputs with the same speaker and all of them work fine. No other known defects with the unit. Is channel 4 on my unit just defective?

RME Fireface 400
OSX 10.14.6
Mac Mini 2018

Any tips very much appreciated. Thanks!

  • waedi
  • DAW Mastermind
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  • From: Swiss Zürich
  • Registered: 2020-12-08
  • Posts: 4,181

Re: White noise issue only with line output 4

Can you do Loopback that Line-out 4 and see the noise in Digicheck ?
May you can record that noise a few seconds and put a link here ?
A friend of mine has a FF400, I will ask him to check the Out4.
Have you tried a total reset in Totalmix already ?

M1-Sequoia, Madiface Pro, Digiface USB, Babyface silver and blue
  • Registered: 2021-02-12
  • Posts: 4

Re: White noise issue only with line output 4

Here's a recording I did of the white noise coming from output 4. Yet again, there was no noise present at all until I passed audio through it, and then the noise began and did not go away until I unplugged it.

*check speaker volume before opening*
https://drive.google.com/file/d/1zUlKwi … xFIjc/view

I did a total reset in Totalmix and the problem persists. I do not think it has anything to do with routing since I've gone through and dropped every fader to 0 and the noise is still there. Even when there is no signal whatsoever on any channel in Totalmix, output 4 is still outputting this noise.

Thanks for the ideas waedi. Hopefully I can track this down and get it resolved somehow.

  • waedi
  • DAW Mastermind
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  • From: Swiss Zürich
  • Registered: 2020-12-08
  • Posts: 4,181

Re: White noise issue only with line output 4

What a hellfire !
The next test I would do is a standalone adat converter test.
Disconnect from computer and connect via adat to another interface and see if the noise is still there.
If yes, I would contact RME Support for repair.

M1-Sequoia, Madiface Pro, Digiface USB, Babyface silver and blue
  • Registered: 2021-02-12
  • Posts: 4

Re: White noise issue only with line output 4

Hey waedi,

Unfortunately I do not have another interface here with me right now to test through ADAT. I'll see if I can run over to a friend's place soon to test per your recommendation.

Any ideas on what it could be or if its fixable at home? I imagine its something to do with the AD conversion on that channel?

6 Reply by waedi (edited by waedi 2021-02-12 23:31:02)

  • waedi
  • DAW Mastermind
  • Online
  • From: Swiss Zürich
  • Registered: 2020-12-08
  • Posts: 4,181

Re: White noise issue only with line output 4

I have probably the same idea as you, the converter of output 4 is kaputt.
In this case homerepair seems to be nearly impossible.
Soldering SMD parts is too microscopic for me.
But there is something odd also, you say the noise comes when you play audio thru this channel.
Is it silent after powering up ? And the noise starts by play audio ?
And when the audio stops, then the noise is still there ?
You can repeat the issue by triggering it with play audio ?
There is another test you can do without any other devices.
You make a routing in Totalmix, from input 4 (or any other input) direct out to output 4. Or from input 3/4 to output 3/4.
Then disconnect the Fireface (maybe shutdown the computer first).
The routing should be stored inside the Fireface.
Power on the Fireface and play something to the input 3/4 and listen what comes out from output 3/4.
When you still can trigger the noise on output 4, then we know, the issue do not come from the computer, it is inside the Fireface.
I hope the fail comes from the computer...

M1-Sequoia, Madiface Pro, Digiface USB, Babyface silver and blue

7 Reply by ricky_ricardo (edited by ricky_ricardo 2021-02-12 23:55:58)

  • Registered: 2021-02-12
  • Posts: 4

Re: White noise issue only with line output 4

Actually, upon further consideration, I think that output 4 is always outputting white noise even when I'm not playing audio. I was using my speaker to test the outputs, and I believe the speaker actually has an audio threshold gate built in before it starts playing audio. That's why I wasn't hearing it until I passed audio, because the white noise was quiet enough to not trigger the speaker to turn on and play by itself. I needed to play louder audio to trigger the speaker to turn on; hence me thinking there was no noise before playing anything.

Now I've noticed that anytime I plug output 4 into any input, I see the noise on Totalmix. So it does not depend on putting audio through output 4, its making this noise constantly.

Because of this, I have to imagine that the problem is coming from inside the Fireface 400, since I do not need to trigger the noise with anything from the computer.