One question that comes up a lot about the new AirLens is it's lack of a USB output.
To explain, the AirLens has two galvanically isolated outputs to feed your DAC: our preferred I2S and a RCA/coax that can feed any DAC.
Clearly, if you have a DAC that supports the I2S format (where the clocks and data are separated on their own data lines), that's the best sounding option. Why? Simply because the data isn't multiplexed into a single stream (the S/PDIF format) that has to then be demultiplexed back into the I2S format.
Two less steps.
But, let us not fool ourselves into believing that the best alternative to I2S is to be found in the USB input. That is simply not true. In multiple listening tests and over years of playing with these formats I can tell you that, without a doubt, the coax input on your DAC—when fed the appropriately constructed and isolated digital audio stream—will sound far better than a computer plugged into your DAC through USB (and this applies to using a USB reclocker like the Matrix).
This is the exact reason we did not put a USB output on the AirLens. We wanted to make sure that for those of you that don't have a DirectStream or DAC that supports the I2S transport over HDMI standard we created some years ago, that the next best option is available to you in the coax/RCA output (and no, we've not found any sonic advantage in the XLR AES/EBU version of the coax S/PDIF output).
Using coax is hardly a compromise. Compared to any other means of streaming data into your DAC—other than I2S—you'll find the coax output of the AirLens to be as good as you've heard.