Raspberry Pi I2S to SPDIF Hat

Not sure why in the world you'd do this...? ABX testing 2 Dac's is all I can think of...

 

Hi Scott, Feeding 2 digital amp (FDA) with the same music stream will allow us doing bi Amp.

 

Hi Michael,

Did you check out the Hifiberry Digi+ PRO driver?

https://github.com/raspberrypi/linux/pull/1583

This is already available in the 4.4.19 kernel.

Maybe the SPD2 will work with it?

 

Hi, Scott, thank you for your reply.
I've just ordered the board.
I will test when I receive it.

 

I am testing that this week. I had to move the crystals around so that the GPIO usage matched, but it should be compatible. I will know more later this week.

Cheers,
Michael

 

Update on SPD2:

After testing and gathering feedback from you guys, we have decided to fold the functionality of the SPD2 and our DAC1 into a single, larger (same size as the Pi) board. This board will function using the off the shelf Hifiberry DAC+ Pro driver for both analog and digital. We will offer it in 3 flavors, full, digital only and analog only. Note that in the digital only mode, the DAC+ Pro driver will not work because the PCM5122 DAC is used for clock select. In that mode we use the Pi GPIO, mapped to be compatible with their newer Digi+ Pro driver for clock selection.

We made some small improvements based on suggestions from you guys. We added LED's to indicate which clock base was selected, 44.1Khz or 48Khz. We modified the BNC output to allow full AES/EBU levels (1V P-P) or by removing a jumper, RCA Coax levels (0.6V P-P). We added a header for monitoring the I2S bus as well as a header that is compatible with the IQAudio Rotary Encoder/IrDA option. We kept the external power option since we feel it may be of value with the DAC, even if it has limited value with the digital side. Power is still provided via the very low noise LT3042 and the dual low jitter NDK clocks are there, for both the DAC and the digital transmitter.

BTW, I will be sending one of these to each of the folks on the test dummies list including the guys who did not get a SPD2 earlier. Just let me know you're still interested. And I would be greatly appreciative if you would be willing to test the DAC side as well. Time frame is in about 3 weeks. Our move is completed and the dust has mostly settled! Thanks again for all your support and help!

Here are a few 3D captures of what the board looks like:

 

I've been watching this progress from the sidelines for a while with great interest. I'm currently using a RPi3 as a Roon Bridge and I'm very much looking forward to the AES feature of your board as both my DACs support it. Great to see it's progressing so well. Big thanks to you and the crash test dummies .

 

Sure @Michael Kelly . Would you like us to send you email to confirm, or will this suffice? I have more things to compare it against at this time, so it will be an even better comparison.

 

Finally!

Who is on the list as testdummies?
II think I asked, but not sure I was approved

 

I have the following who got a SPD2:
vastx
tbooey
fraggler

And the following who did not get one:
pmorgan
wfojas
mban

Please get back to me in the next few weeks with your interest and updated address info. Beyond these guys we will be offering a steep discount (30%) to anyone from this forum. I am having 20 built up so we'll have some reasonable stock.

 

@Michael Kelly Looks like I fell off the list! Oh no! Only 3 test boards?

 

That's why I listed them. You are now back on the list! Anyone else I forgot?

Cheers,
Michael

 

[

I also asked to be inline in the beginning.
Vastx convinced me...
.

 

@Michael Kelly Count me in on this one, I missed out on the last round. I PMed you with my info. Thanks!

 

Hi,

I am guessing you mean the XLR, and the BNC? There is no digital RCA?

Thanks
Bob

 

Voltage levels for AES BNC coax are 1V P-P. But, SPDIF Coax via RCA (if the user puts in a BNC to RCA adapter) need to be lower, 0.6V P- P. This insures consumer SPDIF via RCA will work correctly.

Make sense?

Cheers,
Michael

 

And they can just get a BNC->RCA adapter (75 ohm) if needed. Brilliant!