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DAC Recommendation for DIY media player with Raspberry Pi and miniDSP balanced

PeetSahat

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Hello everyone,
I'm currently looking for a DAC for a media player that incorporates a Raspberry Pi 3b+ and a miniDSP balanced DSP.
Ideally, I'd like to bypass the ADC of the miniDSP and instead utilize its I2S input.
However, I'm uncertain if the RPi can be directly connected to the miniDSP via I2S.
Additionally, I plan to implement an analog input as a secondary audio source.
Since the I2S <> analog input can only be switched within the miniDSP plugin, an ADC is required for the AUX in.
So, the signal chain would resemble something like this for both I2S or analog input on the miniDSP:


1703729888235.png


Any recommendations would be much appreciated. Maybe there are even better solutions?

Cheers!

EDIT: There's a mistake in the schematics. For I2S output to the minidsp a USB to I2S converter is needed instead of a DAC.
 
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JustJones

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Which minidsp are you using? I'm not sure you can bypass the DSP functionality.
 
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PeetSahat

PeetSahat

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You can grab I2S directly from raspberry if you want.
Do you know about the exact procedure? Master, slave, clock settings?

Which minidsp are you using? I'm not sure you can bypass the DSP functionality.
I'm using the miniDSP 2x4 balanced. It has a GPIO port with I2S functionality.
The analog>digital input conversion can be bypassed and a digital signal can be directly fed to the DSP.
 

renaudrenaud

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Do you know about the exact procedure? Master, slave, clock settings?


I'm using the miniDSP 2x4 balanced. It has a GPIO port with I2S functionality.
The analog>digital input conversion can be bypassed and a digital signal can be directly fed to the DSP.
Cannot find what I have done many many years ago with inexpensive board grabbing the I2S from the GPIO to an inexpensive PCM5102 card, but there some explanations here (or elsewhere) :


Another link


It is working but you have to keep your cables short.

Frankly speaking, since with have excellent DAC with USB I never done it again.

Probably you have to activate the I2S output from raspi-config.

Not at home, in holidays, cannot help you more.
 
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TaxTime

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Pi does not have an MCLK output so if using i2s, you would need some kind of reclocker such as IanCanada's board unless you are able to find an i2s output board that includes a clock or if the DAC does not need the MCLK signal from the source.
 

JustJones

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Do you know about the exact procedure? Master, slave, clock settings?


I'm using the miniDSP 2x4 balanced. It has a GPIO port with I2S functionality.
The analog>digital input conversion can be bypassed and a digital signal can be directly fed to the DSP.
Sorry, I see you're right. I never fooled with the 2x4 balanced kit. I assume you meant the kit not the boxed 2x4 balanced as Minidsp says to only bypass if using the kit.
 

TaxTime

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Is it the 2x4 HD (which has no balanced i/o), or is it the Flex (which can be purchased with balanced i/o) - I don't see a product called "2x4 balanced?"
 

JustJones

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Is it the 2x4 HD (which has no balanced i/o), or is it the Flex (which can be purchased with balanced i/o) - I don't see a product called "2x4 balanced?"
Here's a photo of the 2x4 balanced kit. I see them for sale in the EU but not in the US but they might be. But this is this product at any rate.


1703860066464.png
 

TaxTime

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Based on the pinouts of the two boards, it SEEMS like they would work together (though the USB board's capability far exceeds the MiniDSP). That said, with differing brands, nothing is guaranteed. Have you checked with either manufacturer?

I see that on Audiohobby's website that there is a MiniDSP branded USB board - although the description says it's intended for the 2x8 or 8x8, perhaps it can be used with the 2x4? It may be just being described as being specific to 2x8/8x8 because it is designed as an expansion board, so there is likely a SPECIFIC place on the 2x8/8x8 board, but perhaps it can still be used with the 2x4 (consult with MiniDSP).
 

TaxTime

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Found the answer regarding Digi-FP with 2x4 - "no"
 
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PeetSahat

PeetSahat

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I will give it a try with the USB to I2S interface. With around 40 bucks it won't be too much of a loss. I also found an I2S switch (2xIn>1xOut) to implement an ADC for the analog source.
 
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PeetSahat

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I bought the Amanero USB to I2S interface (https://www.amanero.com/drivers/combo384-D.pdf).
Now I need a hint on how to connect it with the miniDSP board.
The miniDSP runs in slave mode.
Kodi's audio output can be fixed at 48 kHz so that shouldn't be a problem.

According to the schematics below my guess for the correct connection is as follows:

Amanero <> miniDSP
  • Pin 3 > Pin 10
  • Pin 4 > Pin 15
  • Pin 5 > Pin 14
  • Pin 6 > Pin 9
  • Pin 8 > Pin 5 or any of the grounds respectively

Am I missing something? Would that be correct? Any help is much appreciated!




Amanero I2S output

1704721939507.png


miniDSP 2x4 I2S input
1704721819744.png
 

TaxTime

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I would consult with MiniDSP, as they would be most familiar with the signal requirements of their products. For example, if the circuit uses an LVDS receiver. Although unlikely, I don't have a MiniDSP anything.
 

mdsimon2

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I bought the Amanero USB to I2S interface (https://www.amanero.com/drivers/combo384-D.pdf).
Now I need a hint on how to connect it with the miniDSP board.
The miniDSP runs in slave mode.
Kodi's audio output can be fixed at 48 kHz so that shouldn't be a problem.

According to the schematics below my guess for the correct connection is as follows:

Amanero <> miniDSP
  • Pin 3 > Pin 10
  • Pin 4 > Pin 15
  • Pin 5 > Pin 14
  • Pin 6 > Pin 9
  • Pin 8 > Pin 5 or any of the grounds respectively

Am I missing something? Would that be correct? Any help is much appreciated!




Amanero I2S output

View attachment 340522

miniDSP 2x4 I2S input
View attachment 340521

I don't think the Amanero will work with the 2x4, the 2x4 needs a 12.288 MHz master clock and the Amanero only has a 24.576 MHz master clock. See link below for more info with I2S interfacing with the 2x4.


Michael
 
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PeetSahat

PeetSahat

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mdsimon2

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I believe the prescaler is for when you are using an external high frequency clock, for example if you are using 98.304 MHz / 90.3168 MHz clocks you would use MCLK / 4 to divide down to get to 24.576 MHz / 22.5792 MHz -> https://www.amanero.com/drivers/AN-06.pdf.

However, it looks like there are other firmware versions that will output a 12.288 MHz master clock -> https://amanero.com/combo384_firmware.htm, specifically the MasterDF1706 firmware looks like it will do what you want.

Michael
 
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