Have the part in 2009 bought and rarely had in service. The same problem as "Daniel". I close my laptop via 3.5mm jack - on to cinch my Pioneer AVR. It hums when the laptop is connected to AC power adapter. This hum I wanted to remove 2000 H through expensive Oehlbach NB. The hum disappears, but the volume of the signal (in my case: Laptop Sound) is dramatically affected, as the audio quality suffers. Had I not thought of Oehlbach - was my first and only device of this brand. My solutions: - Laptop with battery operated (not always possible) - A laptop with HDMI, optical audio output, etc. use - The laptop with an external (USB) sound card provide that similar to an optical sound output offers. Can eg "Creative Sound Blaster X-FI Surround 5.1 Pro external soundcard" recommend. Had deployed all times solutions. Only the Oehlbach device I no longer need. Just think there are better alternatives, I would the "Ground Loop Isolator Eq-205" try it. Costs only 15 instead of the totally exaggerated 60th
