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DAC+ Pro - external power supply

The analog part of the DAC+ Pro can be powered independent from the power supply of the Raspberry Pi and the digital part of the circuit. However, a small modification on the board is needed:

You need to de-solder the resistor R14 and connect your external 5V power supply to the pin header P3 (left GND, right +5V)

Note that this modification voids the warranty. We recommend it only for experienced makers.

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Comments

  • Avatar
    exo

    Hey, what effect the sound is this modification?

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    k.mattitsch

    I would love to see this for AVDD's 3V3 after the LDO (no great component soundwise) and the two oscillator's 3V3 on pin 4 so that the clocks can get its own power supply / regulator.
    Soundwise there's a lot to get out of this if you separate the critical sections (most noticeable on dac's analog section) from the rest. I think the clock would benefit too. I want to try it out but I'm not sure yet if I will manage to separate their pin4 from the main 3V3.

  • Avatar
    chris4

    What are the specs for the power needed for this? What's the minimum it needs?

  • Avatar
    chris4

    Whilst I'm about it, shouldn't there be a bridge across the hole where R14 was?

  • Avatar
    christian1

    Hi Chris4, If you look a R14 "resistor", it's marker 0. So this is a bridge to link the analog section of the DAC to RPi power rail. By removing this bridge, it alloes you to use an external power supply that isalate the analog section from noise generated by the Pi supply. Even if that may look overkill, I recommend the use of a 5V 3 Amp analog power supply. The result is STUNNING. It wort to try it!

  • Avatar
    Mark Bridges

    Hello, is there a power up sequence that should be observed when the RPi and DAC+ are powered up; i.e. should the DAC+ be powered up before the RPi? I have had a few issues powering them separately, such as the hardware volume stopped working and the output went full volume (ouch!). But everything works after the settings are reentered. I am using Volumio.

    Concerning the sound improvements, there is as big an improvement going to a separate linear regulated supply for the DAC+ as there was going from a common switching supply to a common linear regulated supply. I am using an iPad charger for the RPi, and a bench linear 5V 3A supply for the DAC+, with R14 removed. The sound is FAR better than I had hoped for. This is one terrific sounding rig!

  • Avatar
    Nat W. Garrison, Jr.

    From watching Hans Beekhuyzen's video reviews, he says that it makes a very big difference also. So from Mark's comments above, you need a linear 5V 3A power supply. I'm wondering if anyone knows of a good power supply that would work in the United States.

  • Avatar
    Cyril Calmes

    I'm really surprised to read that to power the DAC + PRO, I need a 5V 3A power supply.
    On another thread, I read :

    For the external power supply, you need to remove R14 (near the 5V header). Current consumption is quite low, we haven't specifically measured it, but it should not bore more than 20-30mA. If you are already using an extra power supply, I would recommend at least 100mA.

    Edited by Cyril Calmes
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    HiFiBerry team

    You only need a 3A power supply when you power teh DAC+ AND the Raspberry Pi.