606man wrote:You CAN, in fact, record your patterns to your computer through USB. It's actually really simple.
1 - make sure your USB audio mode is set to MIX [in the menu].
2 - make sure your audio editor is set to record.
3 - make sure the cable is plugged in.
4 - press play on the 606.
done. digital recording through USB!
Oh I LIKE this! Got digital recording through USB working - I can record my patterns, mess around with them in Audacity, load them back into the SP-606, do more things, record them back into Audacity, oh yes!!

Thank you 606man, you're a lifesaver.
Going back to the noise issue, I have a new USB cable, it has improved the noise very slightly but not much. So, I assume my soundcard is the problem. Such is life, I can live with this.
Next trick is to work out how to upload patterns from Kinetic to the SP-606...