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Noise Issues on Raspberry Pi A+

Former Member

Hello All - I just purchase the element14 Pi A+ at microcenter and am having a noise issue with the board. Immediately upon power up the 1/8 output is extremely noisy, to the point that it would be useless for my application (soundfont player) Also there's all sort of weird aliasing on the audio, particularly on the low end. Does anyone else have this issue, or is it possible that it's just my board and it's defective? Do you think the HDMI out would fare any better?  Any help is greatly appreciated. Thanks.

 

Best,

 

Bob

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  • 0 in reply to Former Member

    Hi Bob,

     

    Usually the entire system needs to be examined when it comes to analog audio - there could be screening issues, power supply issues, ground loops and so on. None of this is under control because no-one knows

    which power supply will get used with the RPI, which audio amplifier, which cables, etc. The RPI has no separation of analog or digital supplies either - (guessing - there is no schematic).

     

    As you probably know, with digital audio this matters far less, and while there may be jitter issues depending on the overall system, many people can't hear it - with digital the leap in quality is significant compared to the analog jack output.

    The HiFi berry should in theory be good - it uses a fairly good DAC from TI - I used a similar DAC in a BeagleBone Black quite a while ago and the quality I got was good. There is a recorded file at that link if you want to study the sound output.

     

    The Cirrus card can do audio input too - and should be extremely good quality, since the entire board is custom designed by Cirrus.

    I've not used the Hi-fi berry nor Cirrus, so these are just opinions.

     

    (Link appears broken, URL is BBB - Building a DAC - part 2 )

  • 0 in reply to shabaz

    Thanks Shabaz - I will definitely check out the Cirrus card too.  Interesting, as I am new to this stuff, I didn't really ponder the potential issues of open source hardware and consistency/quality.  A little learning curve for me I guess. If I learn anything I'll post it back here. Thanks again for your help!