i need help for making a DAC for better sound quality

Discussion in 'Digital Circuit Design' started by ducher, Sep 23, 2017.

  1. ducher

    Thread Starter Member

    May 17, 2017
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    Hallo everyone,
    I'm working on a DAC (digital to analog converter) I want to have a USB input and a headphone-jack output and that's it.
    it need to be powerd by the USB. this is my overal plan:
    [PC] --USB--> [MCU/DSP] --I2S--> [DAC] --Analog/Raw-->[Gain/Filter] --Analog/Line-Level--> [Power Amp]--Analog/Phone-Level--> [Headphone]

    I have found schematics online (see file) I want to make my own design with the schematics i found. but i don't understand it completely.
    Can someone explain me how it works. I'm a student that's why i'm not so good at it yet :p
    Thank you so much for helping me out!!
     
  2. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    What part don't you understand?
     
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  3. ducher

    Thread Starter Member

    May 17, 2017
    47
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    is the signal amplefied in this circuit or do i need an external amplefier?
    the OPA1622 (sheet number 9) has 11 connection points in this schematic, but when i check the datasheet I see only 10 connection points.
    in sheet number one you can find the whole circuit, I don't understand the part with the audio-xo, how it's connected.
    in sheet number 2 you can find the audioprocessor, the U81 is connected to it and requiers SPI flash. do i need to program this or is this already done when i buy those chips.

    Hope you can help me out, i will really appreciat that.
    (sorry for the bad english)

    btw thanks for responding on my post
     
  4. ducher

    Thread Starter Member

    May 17, 2017
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    i have one more question: is every chip sold in different packages?
     
  5. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    On the OPA1622 there is a thermal pad below the chip.
    In the schematic this pad is called pin 11:

    OPA1622_pinout.png

    Bertus
     
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  6. ducher

    Thread Starter Member

    May 17, 2017
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    do i need to solder this thermal pad, is that doable by hand?
     
  7. bertus

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    ducher likes this.
  8. ducher

    Thread Starter Member

    May 17, 2017
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    thank you for the information :), do you know the answers on my previous questions?
     
  9. Sensacell

    Moderator

    Jun 19, 2012
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    Do you have the source code for this thing?

    Although it may seem like a garden-variety USB device, it's actually a very difficult project, unless you have have high-level design, development and troubleshooting experience. There are a million reasons why it won't work right the first time, are you up to the task?

    Very few "projects from the internet" actually work, most are incomplete, or poorly designed.

    Not trying to be a wet blanket here, just providing some perspective.
     
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  10. ducher

    Thread Starter Member

    May 17, 2017
    47
    1
    Maybe your right, but i have the gerber files, and the company where i'm a intern will make the PCB for me. so I only need to solder the components on the right place. But I do not only want to make it, i'm trying to understand the circuit so i can learn from it and maybe design my own pcb with the exact same circuit :)

    Do you know the questions i asked above? it would realy help me
     
  11. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    It sounds like you have the hardware worked out but there is software code that must be loaded into the microcontroller. Do you have the code?
     
  12. ducher

    Thread Starter Member

    May 17, 2017
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  13. ducher

    Thread Starter Member

    May 17, 2017
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    can someone tell me de difference between the SIT2001 / SIT9201 and the DSC601JL1A
    thanks
     
  14. ducher

    Thread Starter Member

    May 17, 2017
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    which microcontroller? is that this code:
    https://summivox.wordpress.com/2016/12/22/spi-flash-through-bus-pirate/ How can i upload the code to the microcontroller?
    do i need to make a bus pirate for that?
     
  15. GopherT

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  16. ducher

    Thread Starter Member

    May 17, 2017
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    maybe not if you help me out
     
  17. philba

    Active Member

    Aug 17, 2017
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    You are clearly starting at 0. You'll need to learn so much to get to where you want to be. Maybe if some kind soul did it all for you...

    If you want to do it, start by learning microcontroller programming. Arduinos are pretty easy to get started with and there are lots of tutorials on them. You may be wanting a DAC but that's only a tiny piece of what you have described. Once you understand programming micros, take a look at the Teensy 3.2 and the Audio board that goes with it. That can do all of what you want.
     
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  18. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Ok, read the datasheet for all the components. Use a breadboard and make some “proof of concept” circuits to make sure you understand how each component works. Then ask questions.
     
  19. bertus

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  20. ducher

    Thread Starter Member

    May 17, 2017
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    Do you know a cheap SPI flash programmer for usb.
    do you know the code for this project by chance ? :)

    I guesse 706-1334-ND is the part i need to program with SPI flahs code, is that correct
    do you maybe know a chip which is already programmed with this code,
    (this part is connected to the audio processor with QSPI_NSS, QSPI_SCK, QSPI_D0 QSPI_D1, QSPI_D2, QSPI_D3)

    thanks already
     
    Last edited: Oct 3, 2017
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