Apple Mac USB connection problems

Problem: Apple-Mac <> USB <> DAC-AMP connection lost after 4 hours.
Solution found:
With the release of the OS X Mountain Lion v10.8.2 supplemental updates, a new feature was introduced to enter SAFE sleep after 4 hours of the computer being connected to AC power. This is an effort to comply with the European Energy Standards. This will occur if there is no wireless, ethernet or device activity. Settings can be changed using Terminal app (Finder/Go/Utilities/Terminal)

  1. When in Terminal application type to show current configuration sleep/hibernate/etc:
    pmset -g
  2. Change your standbydelay to 86400. Is number of seconds in 24 hours. Here’s the command:
    sudo pmset -a standbydelay 86400
  3. Change autopoweroffdelay to 86400. Here’s the command:
    sudo pmset -a autopoweroffdelay 86400
  4. At last but not least change autopoweroff to 0. Here’s the command:
    sudo pmset -a autopoweroff 0

Reboot system and check your new settings by command: pmset -g
Since I changed these settings no more going into Safe sleep!
No more losing USB connection between Mac and external DAC / AMP.

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