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ADAU1701 issue, FILTD

Category: Hardware
Product Number: Adau1701
Software Version: NA
I have a problem with the ADAU1701, 
it is working on active Electrovoice
and FBT booths working in selfboot mode,
it starts working fine but suddenly it starts
to generate a noise and the audio fades,
the voltage on the FiltD pin increases
from 1.6 V to 2.7V, I have already changed the ADAU,
I have changed the capacitors of FiltD, FiltA, CM,
but the problem still continues,
I have 4 cards with the same problem and
I have not been able to solve them, can you help me.
I have found that in some cases instead of increasing
the voltage in FiltD it decreases and it is solved
by changing the capacitors but in this case it does
not decrease but instead increases and therefore the
dsp generates noise in the outputs and the audio
does not pass.
  • Hello Oscar2022,

    This is very unusual. So I have many questions and would need more information.

    What happens to the CM pin voltage when the FILTD increases?

    How many cards are working perfect?

    Have you looked at the FILTD pin with an oscilloscope? I am wondering if it is a high frequency signal on the pin? Take a screenshot if it is anything but a DC signal on the pin. 

    Now I need a lot of system info.

    What is the master clock frequency and what is it's source? 

    Are you using the serial port? If you are then what is the sampling rate? Serial Format? Which device is the clock master?

    Look at your power rails, both power and ground with an oscilloscope to see if there is RF or other high frequency noise? Take screenshots if it looks abnormal. 

    I would like to see your schematic and your PCB layout. You can send it to me in a PM is you need to. 

    Dave T

  • Hi there,
    Is your issue to do with existing products or your own design? Not quite sure what you're asking ...

    If these issues are from existing products I'd suggest finding a forum that deals with troubleshooting pro audio products,
    you'll find experienced techs that'd probably know exactly what goes bad on the boards and how to promptly get them back up.

    I have stacks of experience with RCF, QSC and NEXO pro audio stuff and rarely find anything that goes wrong with sigmaDSP chips in those products, maybe once a corrupted EEPROM external to the DSP...