Why have an earth lift switch on a DI box?
Why have an earth lift switch on a DI box?
I know what an earth switch does and when to use it, but why is there a switch? Why not have an earth lift as part of the circuit and leave it permanently on. Does it do anything detrimental to the sound?
Re: Why have an earth lift switch on a DI box?
The reason a ground-lift option is provided at all is to break a ground-loop that can exist between the mains-powered (class-1) recording equipment connected to the DI's balanced output, and a grounded amp (etc) connected to the link/thru output.
However, in a situation where a guitar is feeding an interface/mixer/recorder directly -- and there is no through (link) connection to an amp -- the guitar will need to receive a hard ground connection to minimise interference and spurious pickup of unwanted noises.
If the ground-lift was permanent, the earthy side of the guitar would 'float' and the whole instrument would act as an aerial to pickup all manner of nasties.
Although some DI boxes _do_ have a permanent arrangement intended to minimise ground-loop currents while still providing a reasonably solid ground as a convenient compromise... interference is potentially more likely.
H
However, in a situation where a guitar is feeding an interface/mixer/recorder directly -- and there is no through (link) connection to an amp -- the guitar will need to receive a hard ground connection to minimise interference and spurious pickup of unwanted noises.
If the ground-lift was permanent, the earthy side of the guitar would 'float' and the whole instrument would act as an aerial to pickup all manner of nasties.
Although some DI boxes _do_ have a permanent arrangement intended to minimise ground-loop currents while still providing a reasonably solid ground as a convenient compromise... interference is potentially more likely.
H
Last edited by Hugh Robjohns on Tue Oct 22, 2019 10:07 am, edited 4 times in total.
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- Hugh Robjohns
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(But generally posting my own personal views and not necessarily those of SOS, the company or the magazine!)
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Re: Why have an earth lift switch on a DI box?
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- Hugh Robjohns
Moderator -
Posts: 43691 Joined: Fri Jul 25, 2003 12:00 am
Location: Worcestershire, UK
Contact:
Technical Editor, Sound On Sound...
(But generally posting my own personal views and not necessarily those of SOS, the company or the magazine!)
In my world, things get less strange when I read the manual...
(But generally posting my own personal views and not necessarily those of SOS, the company or the magazine!)
In my world, things get less strange when I read the manual...