There are a growing number of DACs in the marketplace: affordable and competent and mainly Chinese: Topping, S.M.S.L, Gustard, Denafrips, Holo Audio etc. My REFERENCE•M2 system uses Chord Electronics Mojo2 for its unbeatable performance, 5VDC power - and affordability. For REFERENCE•M2/DX I utilize DBNC (dual BNC) from SRC-DX to the Mojo2 but the digital signal from SOURCE to SRC-DX relies on USB transport. Fundamental to this are my products: OPTO•USB, USB•FILTER and my shielded USB cable with ferrites. Note that USB•FILTER is has native USB-C connections but has full compatibility with USB-A using an adapters option.
The combination of OPTO•USB's 100% optical galvanic isolation combined with USB•FILTER x2 (applied at SOURCE output and DAC input) allows REFERENCE•M2/USB to nearly match REFERENCE•M2/DX for transparency and overall sound quality. For a lower cost option, the combination of my shielded USB cable with ferrites combined with USB•FILTER x1 (applied at SOURCE) provides excellent isolation.
I will be promoting this solution and looking to evaluate several USB DAC models in the coming year. The first non-Chord DAC on my docket is the Holo Audio Cyan2. Due to the Cyan2's proprietary USB chip and firmware, my recommendation is the non OPTO•USB signal solution. For Chord (or other DAC's which use industry standard USB receiver chips) use the OPTO•USB signal solution for best performance.
