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Author Topic: Ground Lifting  (Read 1231 times)

Drew Curtis

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Ground Lifting
« on: March 02, 2006, 04:46:13 PM »

I'm interning at a small club in chicago.

apparently the ground effects signal to the board if run thru a DI on stage, the house engineer tells me to put a ground lift adapter on bass amps when a signal is taken straight from the bass guitar into a passive DI and  fed into the amp through the parallel in/out of said DI.

he claims that lifting the ground on the amp AND on the DI grounds the signal through the xlr cable plugged into the output of the DI. is this true? is this a safe procedure?
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Evan Kirkendall

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Re: Ground Lifting
« Reply #1 on: March 02, 2006, 05:01:11 PM »

I only lift the gound on the DI boxes or bass Direct outs if I get a buzz. If you are lifting the ground on the AC plug that is a big NO NO. YOU CAN KILL SOMEONE.Do a search on ground lifting and you'll see why. Its been brought up many times before.


Evan
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David Henry

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Re: Ground Lifting
« Reply #2 on: March 02, 2006, 05:08:15 PM »

Evan Kirkendall wrote on Thu, 02 March 2006 17:01

I only lift the gound on the DI boxes or bass Direct outs if I get a buzz.


Generally, I do lift it if there is a buzz, and if you have a venue with "clean" power for tech use only, then buzz is usually not a problem.

Just another $.02

David
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Jason Tubbs

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Re: Ground Lifting
« Reply #3 on: March 02, 2006, 05:15:51 PM »

A "ground lift adapter" is actually a ground adapter.  It is used to ground a device at an outlet where a ground pin is not supported.  That is why there is a little screw terminal attached to it - that gets connected to the chassis of the outlet.  Using a ground adapter to lift ground on a device is stupid at best, fatal at worst.  

jt
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Drew Curtis

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Re: Ground Lifting
« Reply #4 on: March 02, 2006, 05:24:50 PM »

didnt make sense to me when he told me. thanks for clarifying.
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Austin Parker

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Re: Ground Lifting
« Reply #5 on: March 02, 2006, 07:02:15 PM »

Usually noise in the signal path, which can be traced back to 'ground', is a key to Pandora's box. Bad ground on stage could lead one to find bad ground in the VENUE. It is always best to error on the side of safety than on the side of "just because he said so" ; Don't lift ground.
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Austin Parker

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