Home › Forums › Products › Rackmount › h8000FW High Pitched Whine › Reply To: h8000FW High Pitched Whine September 1, 2018 at 11:59 am #150027 nickroseModeratorEventide Staff This is usually caused by ground loops or bad cables, but since it seems to be level sensitive in your case, it could be an A/D or D/A fault. support@eventide.com