A weird noise is driving me mad [SOLVED]

Hey many thanks for your help!
@C0d3man --> I tried with a power bank but the noise is still there :anguished:
@Baggypants --> Yes, the recording was made using the RCA but using jacks the result is the same.
And of course nothing changes using another mixer…

Is it likely to think that the HB DAC+ is gone?

I’d try powering it from a big mobile phone battery pack to rule out the PSU first.

@Baggypants --> did it with two different power banks: the noise remains :weary: (I’ve also tried with another power supply with no joy)

Any procedure to test the HB DAC+ before buying another one? (And is there any warranty on the card?)


Have you tried with the “alsamixer” from command line? Perhaps there is some options there …


@jofemodo and @Baggypants could you post part number, version and manufacturing date of your DAC chip (better: a full READABLE picture of the chip)

Sorry, I meant to tag @sadkermit…

This is from Daniel, the creator of HifiBerry DAC+:

Hi José,
there were no hardware changes in the DAC.
Unfortunately I can’t say anything about this specific problem. It could be a problem of the circuit that the DAC+ is connected to.
If would check what’s on the output of the DAC.
Best regards,


My question about revisions are tied to the TI notes on the PCM512x.

There are two (three, actually) hardware revision of the chip.
The Jan. 2016 revision removed a feature called “Internal Pop-Free Control For Sample-Rate Changes Or Clock Halts”.

Interesting … let see what Daniel says :wink:

Hi @Axeman!
Could you post the link to the TI revision notes?


Re reading the doc, maybe these are revision of DOCUMENTATION and not of the chip itself…
I never liked TI documentation since the 74XX data books :slight_smile:

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Ups! yes … it looks to be Documentation Revision … :wink:

Your Honor, I retire my question and throw myself on the mercy of the court! :rofl:

Good try, Mr. @Axeman! :kissing_heart:

Hey the discussion is getting intriguing… :nerd_face:

@jofemodo --> “If would check what’s on the output of the DAC” sorry if this is a stupid question but does it mean “after the output of the Zynthian”?

Yes, after the output of Zynthian :wink:

Please, specify exactly your full audio chain. What devices are connected downstream from zynthian, what order, what type of connection, etc.

Regarding your mixer, check this:


I didn’t read the article completely, but it seems like some Mackie products having problems with audio levels when recording to digital. Perhaps it could be related …


@jofemodo --> thanks! my full audio chain is:

Zynthian -> RCA LR out or Jack LR out (I get the same noise from both) to -> Mackie 1202 VLZ4 tried all the inputs/channels (and nothing changes with a different mixer: I tried also with a Thomann the t.mix mix 802), I’m listening through my old Sony headphones or through a couple of KRK RP6 Rokit (headphones connected to the headphones out, monitors connected to the main output XLR), that’s all.

Reg the article: it’s about the old Onyx series - analog mixers with integrated digital interface, the 1202 VLZ4 is just a simple analog one and, after all, with another mixer the problem persists… :pensive:

Have you tried the alsamixer from Zynthian’s command line? There are a few options there (although the default should be OK).

These options include things like “automute” feature, etc. I’ve playing with this features, but i can’t reproduce your problem. Anyway, perhaps you can use it to solve it :wink:


@jofemodo THANK YOU!! :heart_eyes: I took a look at alsamixer and yes - the problem was there: the “AutoMute” function was on, turned it off and now the noise is gone!