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PecanPi - Next Generation Raspberry Pi DAC and Streamer

bequietjk

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@orchardaudio Yes! Wondering if the Pecan could accept I2S input. Specifically from my USB transport (Matrix XSPDIF2). I believe you answered my question via email the other day, though.
 

orchardaudio

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es! Wondering if the Pecan could accept I2S input. Specifically from my USB transport (Matrix XSPDIF2). I believe you answered my question via email the other day, though.
The PecanPi can accept an I2S input, that is what it gets from the RaspberryPi. You would have to figure out how to wire it from the XSPDIF2 device. Here is the pinout of the PecanPi:
1574962705986.png



The connection you would need to make are:
1. I2S_DATA
2. I2S_LRCLK
3. I2S_BCLK
4. GND
5. RPI_3V3 -- This has not thing to do with the I2S but the PecanPi needs 3.3V on this pin to enable operation, the current draw is very low <0.5mA.

The 5V on pins 2 and 4 is an output that typically powers the RaspberryPi but is not needed in your case.
 

bequietjk

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Looking at that pinout and understanding it is beyond my scope of knowledge, at the moment. Im willing and able to make this happen for my setup.

If im understanding this correctly, ill need to wire a I2S input jack in the form of HDMI, to the PecanPi so that it can accept the HDMI from the Matrix? That shouldnt be too hard. I'm all for the challenge if it means Burr Brown & balanced DAC happiness!
 
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orchardaudio

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If im understanding this correctly, ill need to wire a I2S input jack to the PecanPi so that it can accept the I2S from the Matrix? That shouldnt be too hard. I'm all for the challenge if it means Burr Brown & balanced DAC happiness!
That is correct. I can prewire the 3.3V for you. So you would only need to wire the I2S.
 

bequietjk

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It seems an HDMI/I2S module is going to be needed for this project. Going over a couple of modules, it seems 5V would be needed to power them anyway, so the 5V output on the PecanPi would come in very handy. In this scenarios I will only be using the PecanPi DAC alone, not streamer.

Would any of these work?
https://www.audiophonics.fr/en/diy-interfaces/i2s-to-hdmi-i2s-module-board-p-10754.html
https://www.audiophonics.fr/en/diy-...dule-hdmi-i2s-lvds-to-i2s-output-p-12422.html
https://www.audiophonics.fr/en/diy-...i-to-i2s-spdif-digital-interface-p-13415.html

Technically, a HDMI to I2S module would be needed and not I2S to HDMI, right? *scratches head*
 

orchardaudio

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bequietjk

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I would make sure that the I2S signals coming out are 3.3V.
How can I use my multimeter to test this? Should I put the multimeter leads on the 'blue' GND + BCLK and SDATA pins?

If the I2S module happens to be outputting 5V, this will need to be lowered to 3.3V. This means having an LDO? Pardon me, I'm still piecing together the basics of electronics and trying to understand fully. This is REALLY exciting and would love to make a DIY project out of the Pecan.

If you'd like, anything further (to prevent clogging this thread up with my concerns), I could continue with my questions via PM.
 

orchardaudio

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If you'd like, anything further (to prevent clogging this thread up with my concerns), I could continue with my questions via PM.
Please send me email. That is easiest for me.

The I2S lines cannot be measured with DMM. You will need scope.

If they are 5V you will need a voltage translator, just find a module that outputs 3.3V for I2S, this will make things much easier. Contact that company that is selling them and ask, they may know.
 

orchardaudio

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I just thought people here might be interested in this project I did for a customer which will also become a future product.

Basically it uses the miniDSP USBStreamer to give the PecanPi DAC a way to connect over USB.

PecanPi_USB.jpg
 

orchardaudio

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orchardaudio

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Is the claimed SNR of XLR output(PecanPiUSB) of 130db the same as SINAD?
No. SINAD is same as THD+N or 110dB.

All my specs are derived using an APx525.
 
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jgirado

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Hi,

Planning to buy your PecanPi DAC and I have 2 questions (for now):

1) Should I wait for the incoming Feb 2020 update? Not interested in balanced headphones (don't have one nor planning to buy one), just in the best possible audio quality DAC (that can be used with my Raspberry Pi 2B). I don't mind waiting a month or two.

2) I'll use the DAC mainly for streaming my [huge] CD library from my NAS, so I'm only interested in DLNA support. Maybe, but not important, Spotify & Pandora. In your opinion from the ones you offer, which software is best for this [DLNA] purpose (I mean, easy to use, free, stable, etc.):
Thanks in advance,
Javier
 
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Hi,

Planning to buy your PecanPi DAC and I have 2 questions (for now):

1) Should I wait for the incoming Feb 2020 update? Not interested in balanced headphones (don't have one nor planning to buy one), just in the best possible audio quality DAC (that can be used with my Raspberry Pi 2B). I don't mind waiting a month or two.

2) I'll use the DAC mainly for streaming my [huge] CD library from my NAS, so I'm only interested in DLNA support. Maybe, but not important, Spotify & Pandora. In your opinion from the ones you offer, which software is best for this [DLNA] purpose (I mean, easy to use, free, stable, etc.):
Thanks in advance,
Javier
Hi Javier,

1. The only PecanPi's I will have available are the one's with the February update. They will be just as good as the existing ones, with the additional support for balanced headphones.

2. Volumio fully supports DLNA and uPnP. This is your best option unless you already have Roon, then Roon endpoint us my recommendation.
 

jgirado

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Hi Javier,

1. The only PecanPi's I will have available are the one's with the February update. They will be just as good as the existing ones, with the additional support for balanced headphones.

2. Volumio fully supports DLNA and uPnP. This is your best option unless you already have Roon, then Roon endpoint us my recommendation.
Thanks for your prompt response, I'll install Volumio and play a little bit (I don't have Roon right now). I'll use one of my USB crappy DACs in the meantime until I decide if I want the case or build mine (need to build on top a XLR switcher, etc.), pot, power supply, etc.

Javier
 

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