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Original question:

TPA3110D2 Hiss Noise

TPA3116D2: Amp self noise/hiss using TPA3116D2

Kevin Zuccaro
Prodigy 20 points
Part Number: TPA3116D2

Hi there,

We are getting an unacceptable level of amp self noise using the 3116D2.  This is my factory in China's execution, and they can't seem to get to the bottom of it. We are also using another company's DSP (1701) and don't know if that is contributing to it.

I did read another thread where they "used a couple of signal transformers to convert the single ended inputs to differential. Pin drop silence now :).". This sounds promising so we will try that, but I just wanted to show your our schematic to see if you can find anything obvious.  Thanks!

  • 0
    TI__Mastermind 19157 points

    Hello Kevin, 

    There are three main differences that I noticed from your board and the TPA3116D2 EVM: 

    1. The EVM implements RCA connectors, what type of connector are you implementing in your single ended application? 

    2. C23, C27, C38, and C39 all have 2.2uF caps instead of 1 uF. 

    3. How is your mute and fault controlled externally, as you can see from the EVM mute and fault are related to each other. 

    Some additional questions are: 

    1. What is the load you are using? The TPA3116D2 supports a load impedance from 3.2 to 8 ohms. 

    2. Schematic says TPA3118 but the question is referencing TPA3116D2, please confirm TPA3116D2. 

    All the best, 

    Carolina 

  • 0 in reply to Caro Walter
    Prodigy 20 points

    Hi Caro,

    Thanks so much for the quick reply.  To answer your questions:

    1. Connectors we're using are RCA, as well as TRS and XLR.

    2 and 3.. I will ask my factory about those when they come back from CNY.

    4. Both drivers are around 4ohm loads.

    5. It is TPA3116D2.  They never updated the schematic from an earlier revisioin.

    Best,

    Kevin

  • 0 in reply to Kevin Zuccaro
    TI__Mastermind 19157 points

    Hello Kevin, 

    I also noticed that the negative input (Pin 5 and Pin 11) are routed back to the part's ground. 

    Could you please connect those two pins to the source ground of the board and see if the hissing noise disappears? 

    All the best, 

    Carolina 

  • 0 in reply to Caro Walter
    TI__Mastermind 19157 points

    Hello Kevin, 

    Due to inactivity, we will close this thread. Please feel free to open a thread for your questions! 

    All the best, 

    Carolina