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Thread: 24 Bit DAC for Teensy

  1. #1
    Senior Member Rolfdegen's Avatar
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    24 Bit DAC for Teensy

    I tested different 24bit DACs on my Teensy 4.1.


    1. PT8211 16-bit DAC
    2. PCM5102A 32-bit DAC Burr Brown
    3. ES9032P 24Bit DAC HIFIberry Board

    Here are spectrum analysis from DACs. The sample rate for PT8211 to 44.1KHz and and the others are 88.2KHz.

    I measured the frequency spectrum of the DAC converter with a measuring Sine tone of 440 Hz from Teensy.

    PT8211 shows large distortions in the overtones. PCM5102A and ES9032 are very good and have very little noise.



    PT8211
    Samplerate: 44.1KHz (PT8211 Teensy driver)


    PCM5102A
    Samplerate: 88.2KHz (I2S1 Teensy driver)


    ES9023P
    Samplerate: 88.2KHz (I2S1 Teensy driver)



    PT8211


    PCM5102A


    ES9023P




    Gruß Rolf
    Last edited by Rolfdegen; 04-18-2021 at 07:24 PM.

  2. #2
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    Interesting to see, but a bit of apples to oranges. We expect different results when measured at double sampling frequency. Doesn't really show that they are better at the same sampling frequency.

  3. #3
    Senior Member Rolfdegen's Avatar
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    I also measured at 44.1KHz and found no harmonic distortion with PCM5102A and ES9023P. Only harmonic distortion with PT8211.

    Increasing the sample rate to 88.2KHz with the PT8211 was no improvement.

  4. #4
    Senior Member Rolfdegen's Avatar
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    A friend made this measurement with PT8211


  5. #5
    Senior Member Rolfdegen's Avatar
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    I made another measurement with PCM5201A and 44.1KHz in my Teensy 4.1 . It's a good result.


  6. #6
    Senior Member Rolfdegen's Avatar
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    I am not satisfied with the PT8211. It sounds bad in my DIY synthesizer. Because of this, I want to use a different DAC.

    The PCM5102A sounds very good and works very well with Teensy 4.1.

    Link: https://forum.pjrc.com/threads/63255...Teensy+Shruthi

  7. #7
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    It's interesting how something like this is so vastly superior. Plus no ground loops when using toslink.

    https://www.audiosciencereview.com/f...-review.12119/

  8. #8
    Senior Member PaulS's Avatar
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    Hallo Rolf,
    Just curious: what measurement program did you use and what ADC?

    Danke,
    Paul

  9. #9
    Senior Member Rolfdegen's Avatar
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    I use 32Bit DAC PCM5102A and Audacity.

    The 440Hz sines wave is generated by AudioSynthWaveform from Teensy 4.1 and LCK 44.1KHz, BCK 2.857MHz.

  10. #10
    Senior Member PaulS's Avatar
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    Hallo Rolf,
    Thanks for your reply. I was wondering what A/D-converter you were using for your measurements. Some USB audio device?

    Paul

  11. #11
    Senior Member Rolfdegen's Avatar
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    Mixer Behringer QX1222USB

    Link: https://www.behringer.com/behringer/...odelCode=P0AKX

    The measurement signal goes in Mixer analog in and USB out (16Bit 48KHz Samplerate)

  12. #12
    Senior Member PaulS's Avatar
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    Thanks Rolf,
    You might be interested in the measurements I did as well on several DAC's.

    Paul

  13. #13
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    The PT8211 datasheet shows the distortion performance is about 9 or 10 bits equivalent with 0.1 to 0.3%
    being quoted (around -60..-50dB) depending on how close to the full-scale you venture. Its key feature
    is monotonicity to 16 bits, thus the claim for good dynamic range. Monotonicity and linearity are fairly
    independent metrics for ADC/DAC performance.

  14. #14
    Senior Member Rolfdegen's Avatar
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    Thanks all for the information.

    The PCM5102A (right) has very good values for harmonic distortion. I think I using this DAC in my Synth.


  15. #15
    Senior Member fdaniels's Avatar
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    You all might want to kill me, but personally i find the PT8211s sounds quite nice if you are into gritty sounds. Remember, many famous Synthesizers and Samplers had awful D/A (pre 1000 Akais, PPG Wave and especdially Prophet VS come to my mind) yet these added Harmonics are part of their iconic sound. Besides the perpetual disussion about digital filters D/As that are too "slick" are part of the problem Emulations never sound as the original.

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