So I've been contemplating either a new streamer, specifically a Lumin T2 or similar, to replace the Node 2i. Alternatively, a Marantz K1 Ruby to replace the Oppo, allowing me to use the Node 2i into the Ruby DAC. Both options cost around $4K.Node 2i into Ruby DAC? You must be kidding.
I have the SA-10, the brother of Ruby. I tried using it as a DAC with streamers. Even Innuos Zenith Mk2 with Curious USB cable into SA-10 USB DAC input cannot beat the SQ when playing CDs/SACDs directly with SA-10, or playing music files from USB drive attached to SA-10.
If you are keen on Ruby, go for it, but save your money for a much higher quality streamer for use with Ruby as USB DAC.