Dual-Coax (DX) Isolation

Chord DACs sound best with Dual-Coax (DX) input (vs USB). The DX signal is based on the S/PDIF self-clocking protocol and the receiver is directly integrated on the FPGA. The USB signal requires noisy extra clocking/logic and the receiver is on a separate chip. Per the above drawing, here is what I recommend:

STANDARD DX ISOLATION

1. USB•FILTER (with USB-A Adapters). Even a well designed source component with low RF noise USB will also benefit from additional USB filtering. USB-FILTER is an all-passive design with excellent RF/EMI line noise suppression on +5V/GND power and common/differential mode noise suppression on D+/D- data lines. 
2. USB•CABLE. Use your existing well shielded/filtered USB cable or consider my own offering. Keep this cable as short as possible to avoid antenna effects. Alternatively use a commodity USB-A to USB-B straight-thru adapter.
3. SRC•DX. Converts USB to DX. Provides plug-and-play operation with Windows, macOS and Linux. BNC connections ensure reliable transmission of high-speed digital audio. 
4. DC•BLOCK, LP•FILTER. DC•BLOCK and LP•FILTER are in-line devices that will block DC and filter RF noise outside the DX signal passband.
5. DBNC Adapter. This hard shell dual RCA to 3.5mm mini-plug combined with supplied BNC to RCA adapters allows connection of a DX signal to Hugo2 or Mojo2. 

EXTREME DX ISOLATION

1. USB•FILTER (with USB-A Adapters). Even a well designed source component with low RF noise USB will also benefit from additional USB filtering. USB-FILTER is an all-passive design with excellent RF/EMI line noise suppression on +5V/GND power and common/differential mode noise suppression on D+/D- data lines. Note that for EXTREME ISOLATION, I recommend two USB•FILTER: one at the source and one at the output of OPTO•USB.
2. OPTO•USB. The best isolation technology is optical and OPTO•USB is compatible with Chord DACs. Note that OPTO•USB receiver requires ultra-low-noise 5V for optical demodulation to USB.
3. USB•CABLE. Use your existing well shielded/filtered USB cable or consider my own offering. Keep this cable as short as possible to avoid antenna effects. Alternatively use a commodity USB-A to USB-B straight-thru adapter.
4. SRC•DX. Converts USB to DX. Provides plug-and-play operation with Windows, macOS and Linux. BNC connections ensure reliable transmission of high-speed digital audio. 
5. DC•BLOCK, LP•FILTER. DC•BLOCK and LP•FILTER are in-line devices that block DC leakage current and filter RF noise outside the DX signal passband.
6. RF•STOP SE Signal Filter. Uses passive skin effect filtering technology for excellent low pass filtering of DX digital audio with performance superior to traditional filter topologies. Use to (optionally) complement DC•BLOCK and LP•FILTER.