l2t hum

[jpelzel]

Hey all. New l2t user. The l6 link is crystal clear but so far the other inputs give a prominent hum. I have only been able to use a mono instrument cable so far but I am getting the him from multiple sources. Any tips?

[SiWatts69]

With an unbalanced cable, you've always got a significant risk of hum... interference from external power sources. The longer the cable, the more scope for interference. Keep your signal cables short and away from power cables and sources.

In a balanced cable, the interference appears in both the hot and cold signal lines equally, the two subsequently cancelling each other out almost perfectly, but in a mono cable, no such cancelling can occur. In simple terms, the signal processed from a balanced cable is hot - cold. If we have interference picked up equally in both hot and cold, the effect is no interference.

Hot = signal + interference

Cold = interference

Hot - Cold = signal!

 

Additionaly, if you are connecting a mains powered source to your L2T, then, again, there's a strong possibility of "ground loop hum" which is created when the two 'ground' signals become slightly out of phase with each other, typically when the mains sources are separate to each other. When connecting signal from a mains powered item, such as a keyboard, it is often practise to utilise a DI box OR inline signal isolator box unless the powered item already has an isolated output, or the speaker/mixer an isolated input. Bass rigs and Keyboard backline amps commonly have "DI out" sections which take care of it, but if you connect a keyboard direct, you'll very likely get ground loop hum.