Walshspur

Hi Ive just purchased a Weiss 2, ive read that some have found that if you use an adapter at the computer it stops the power going to the dac which isnt needed as the Weiss powers itself. This has resulted in an improved SQ? My question, im very new to all this!! what cable and adapter would i need?? Im using a Mac with both 400-800. Cheers in advance