How to Connect My Nucleus' Output to My DAC's I2S Input?

Core Machine (Operating system/System info/Roon build number)

Nucleus Rev. B

Network Details (Including networking gear model/manufacturer and if on WiFi/Ethernet)

NETGEAR Nighthawk AC1750

Audio Devices (Specify what device you’re using and its connection type - USB/HDMI/etc.)

PS Audio DirectStream DAC from Roon Nucleus via USB cable and controlled by a 5th generation 32GB iPad Air

Description Of Issue

I’ve read that for best results, the I2S input on my DAC is the way to go. Is there a cable that will connect a Nucleus to a DAC in this way?

Unfortunately, it requires more than a cable as the NUC is outputting a format other than I2S. The HDMI physical connector is the only commonality.

I believe USB is your only output option but the Matrix is very well respected and will do the job.

They pop up used from time to time on PS Audio forum as people ebb and flow with system changes.

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So, the USB output from the Nucleus would be plugged into the Matrix and another cable (of some kind) would run from the Matrix to the I2S jack on the DAC?

At some point I had a Holo Spring DAC with a Singxer SU-1 USB>I2S converter, it worked well (not from a Nucleus but from various USB Roon endpoints). I used a good, short HDMI cable to connect the converter to the DAC (which I believe uses the PS Audio I2S HDMI encoding). Singxer has since built fancier converters that I have not tried. If you are into a bit of DIY, a Pi2AES-based Roon endpoint running Ropieee would allow you to separate the DAC from the Roon server with Ethernet, which offers more flexibility and maybe a quality improvement. I own two of these, although not at the moment for I2S output, just for AES output. From what I’ve read, HDMI output from Pi2AES to PS Audio should work.


Wow, to be honest, most of your post is over my head. When it comes to digital, I need things as simple as possible. I’m going to try to break down what you’ve said into bite size pieces to see if I can digest it.

Sorry, I’ll try again. Here’s your current setup (I think)

Here’s what it would be with the Matrix or SU-1 (digital-to-digital converters aka DDCs)

Finally, here’s how it would be with a separate Roon endpoint that outputs I2S over HDMI, such as the Pi2AES:

The DDC setup is the simplest change from your current system. The separate Roon endpoint gives you more flexibility but more complexity in setup and management.


Yes, a regular HDMI cable

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I assume your DirectStream doesn’t have the optional Bridge II Network Card. This would allow it to be a Roon Ready through Ethernet.

Cheers, Greg

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My goodness, that makes it so much easier to understand! I do believe that using your road map, I would be able to set that up. Thank you so much for your illustration! :+1:

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You’re correct, I don’t have the Bridge II card for my DAC. Would having that card give me the same SQ as the setup that @Fernando_Pereira diagrammed for me?

The Bridge II would give you the potential benefits of separating the DAC from the Roon Core with Ethernet (which Roon in general recommends) without the complexity of the 3rd setup I outlined. But I’ve never heard the DirectAudio with or without Bridge II so I can’t speak to quality benefits.

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PS Audio is pretty good about letting you try their components in your own system before you buy, so maybe I’ll try that route.

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The Matrix is head and shoulders above the bridge II in my empirical experience.


That helps a lot, thanks!

Can you tell me how I would set these switches on the bottom of the Matrix?

Sorry, it was @Larry_Post who recommended the Matrix, I never used it.

Sorry, Fernando. :smiley:

Just in case you haven’t purchased something that would take a USB input and output to the I2S input of your PS Audio DAC check this out.

Streaming Audio via the I2S Connection

Have you considered sending the DirectStream back to PS Audio and getting something less finicky? Like a Brooklyn Bridge II or RME ADI 2?