One thing to note when it comes to rDAC is what is used to serve digital music. If it is an HTPC, a game console or any other media server with an optical or coaxial digital output, it is hard to beat the expense of just one digital cable running into A400's digital inputs (in case of boxes that also produce video and have HDMI, you can get away with using the same HDMI cable for both video and digital audio). According to Arcam, a lot of care went into reducing jitter over HDMI so hopefully music will not suffer that way. If, on the other hand, you want to connect a laptop, your best bet for digital music nirvana is an USB->SPDIF converter such as the new Musical Fidelity V-LINK. It can handle anything up to 24/96 and uses asynchronous USB connection (virtually no jitter, much better sounding). At that point, you can compare whether you would like to also do your D/A conversion in this box (and therefore go with rDAC) or use V-LINK and rely on Arcam to do the D/A via optical or coaxial digital input. I think V-LINK route is cheaper (rDAC also uses asynchronous USB). Regardless of your choice, you should bear in mind that only HDMI can handle hi-res multi-channel audio (SPDIF can handle up to 24/96 two channel LPCM). Do not be confused with Dolby Digital or DTS - this is compressed (lossy) multi channel that runs at 16 bits /48kHz. Dirt cheap adaptive USB->Toslink converters can be had if you want to limit yourself to 16/48 (but we are looking at Arcam because we don't, right? .