Digital Cables

maprik

The Bluesound Node (N130/N132/Icon/Nano) supports USB audio output to an external DAC (Digital-to-Analog Converter) by enabling the USB Type-A port for digital audio streaming, which often provides higher quality than optical/coax. To use it, connect a DAC, then go to the BluOS App > Player Drawer > Context Menu (3 dots) > Audio Settings > Select Output, and choose your external DAC; this bypasses internal processing for better fidelity. 

maprik

Let me know what you think of the Supra. Funny enough, I currently run the same Node 130/Iris/Pontus II. Yes to my ears (and a whole bunch of others) the I2S is the best connection

The Node 130 and Pontus II will be upgraded next year, as the rest of my system has finally outgrown the pairing.

@vthokie83 Are you using USB from the Node to the Iris?

@emilian67 I was told (by Chat GPT) that the N130 USB is just for connecting to a storage device and not for audio out. Im not savvy enough to know if there is a difference! Are you using it? Thank you! 

Per Chat GPT: 

Why the Node N130 USB does not work with the IRIS

1. USB role mismatch

Node N130 = USB host that outputs audio only to USB DACs

Denafrips IRIS = USB device that expects a computer/streamer acting as a USB audio source

The Node’s USB stack is restricted:

It does not output generic USB audio streams

It only supports DAC-class devices, not DDCs, reclockers, or format converters

2. Real-world confirmation

This isn’t theoretical:

Multiple users have tested Node → IRIS (and Node → Gaia)

The IRIS does not appear in BluOS as an output option

Denafrips themselves do not list Bluesound Node as a compatible USB source for IRIS

So your current plan — Node → coax → IRIS → I²S → Pontus II — is exactly the correct workaround.

Practical reassurance (important)

You’re not missing out the way it might seem:

The IRIS reclocking + I²S stage does the heavy lifting

Coax from the Node is not the bottleneck once the IRIS takes over

Many Pontus II owners run this exact chain very happily

If you want, next we can:

Compare Node → IRIS vs a true USB streamer → IRIS

Or talk about which streamers do output USB audio to DDCs around your budget

@maprik There seems to be a philosophical difference between manufacturers of digital gear between USB and I²S as the connection of choice.  Either is (usually) better than Coax, TOSLink or AES/EBU - though Aurender recommend their Coax for some streamers.

Your IRIS box tidies up the S/PDIF, reclocks it and outputs the I²S streams (data, bit clock and word clock), the DAC then uses the clock signal from the IRIS, which has been transported over the HDMI cable,  Hence the critical nature of the cable.

Esoteric use a proprietary current based flavor of I²S, ES-Link, for their Grandioso separates.  At $100k or so.  I guess that they decided that the best bang for the buck in the $15k to $30k range was asynchronous USB with a precision clock and a FIFO buffer.

There are (heated) discussions of the merits and problems with USB and I²S on this Roon forum https://community.roonlabs.com/t/usb-and-i2s-which-is-better-for-connecting-dacs/274372/8

Denafrips have chosen I²S as their "flagship" interconnection, and, yes, the cable quality is critical. The routing of that cable may matter also as it should be away from EMI noise. 

This is the sort of discussion that helps to make the equipment side of this hobby fun!