When you touch your device, did the hum/buzz noise decrease? At iFi audio we have found the solution, the Groundhog+. In most cases these noises are likely to be caused by a missing Ground/Earth connection that normally shields your system from such interference and drains away the noise. Having a missing ground can lead to the irritating issue of hum, buzz, hiss and general interference in certain systems where: A system where there is at least one AC mains powered device or has an AC mains charger attached and it has no ground/earth at all. This is when the Groundhog+ becomes your hero, as there are many adapters to utilise any unused port you may have to add a ground to. If the audio system has two or more AC mains powered devices, this is likely to lead to more than one ground/earth connection (select iDefender3.0 instead of the Groundhog+) in which case one of the grounds needs to be disconnected.