How to remove audio hum due to ground loops.
Demokid
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#1
22nd August 2013
Old 22nd August 2013
  #1
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Thread Starter
How to remove audio hum due to ground loops.

Hi,

A lot of people have questions about hum in their audio chain so this topic is how to solve the problem ones and for all.

Here are some information what is causing the hum and how to remove it. For those of you who are lazy and don’t what to read about ground loops just watch the YouTube video.

Ground Loops Explained

Diagnosing and Fixing Ground Loops to Prevent AC Hum/Buzz


And a video which shown how it works and how simple it is to fix.

Hum Eliminators

I use Line Level Shifters on all my equipment which also remove ground loop hum.

The best way to get control over hum is so make (solder) your own audio (cables and jacks). That way you have control on which jacks on the audio cable should have the ground wire cut plus you get the perfect length. I use multi cables with 16 or 24 cables inside so that you don't have hundreds och cables all over the room.

We are talking about jacks (1/4" or XLR) on audio cables. Do not remove ground on power cables or ground inside equipment!!

Jacks on the audio cable connected to an audio output of a device should have the ground wire connected (soldered).

Jacks on the audio cable connected to an audio input e.g. mixer should not have the ground wire soldered only the audio wires. Cut the ground wire and make sure you the complete ground wire. If you have some leads left and it touch theinside of the jack you can get hum. I usually pull and extend the plastic insulation cable, the outside cable a bit over the audio wires.

Regards
Demokid
Demokid
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#2
22nd August 2013
Old 22nd August 2013
  #2
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Hum can also occur in old equipment due to old capacitor in the power supply. Capacitor has a lifespan of about 30 years. If your 30 year old vintage synth, pre-amp start to hum, turn it off and replace the capacitors at ones.

You don’t want a capacitor blow up inside your expensive equipment… it is very messy and can ruin it.
#3
22nd August 2013
Old 22nd August 2013
  #3
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matt thomas's Avatar
 

Most hum issues should be able to be resolved without resorting to products like these, but they are a good last resort, or quick fix.

matt
#4
24th August 2013
Old 24th August 2013
  #4
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LeeYoo's Avatar
 

A transformer based solution like this one should be your last resort.
Leo..
#5
25th August 2013
Old 25th August 2013
  #5
Gear nut
 

How to avoid hum caused by ground loops: don't form ground loops. Use balanced signals wherever possible not just for noise immunity, but so you can "lift" the ground at any points that may cause trouble.
#6
25th August 2013
Old 25th August 2013
  #6
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LeeYoo's Avatar
 

+1
Groundloops are made by you.
Balanced interconnects don't use (dirty) ground to transport audio.
But there are always gremlins around the corner...
Leo..
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