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Electrical loop Headphone Amps
Old 11th September 2011
  #1
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Electrical loop

Hi GS, I have had a issue within the studio for a couple of months now, regarding electrical loop (least that is what I think it is?). Basically, my monitor amps (K + H O300D)are producing different timbres of electrical noise instead of maintaining a constant tone (which is generally so quiet you can not hear it). I have tried many trouble shooting methods, all of which have not resolved the problem. It is not any feedback from computer or interface as I have just had the monitors pluged straight into the wall without any other devices connected.

Has anybody had this issue and do you know any ways of solving it? it is driving me mad! BTW, I am a UK resident so 240v, thanks, Paul
Old 11th September 2011
  #2
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Have you tried a power conditioner?
Old 11th September 2011
  #3
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Quote:
Originally Posted by wado1942 View Post
Have you tried a power conditioner?
Thanks for reply mate, I have not tried one of these yet, will pop down to maplins tomorrow and get one :-)
Old 12th September 2011
  #4
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Verified Member
What do you mean with different timbres?
Low frequency hum? High frequency "whistle"? Tone sweep?
Could well be garbage in electrical the supply provided the earthing is ok. An isolation transformer is likely to help more than a conditioner albeit not exactly a cheap solution.
Old 12th September 2011
  #5
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Powerconditioneer, in most of cases will not reduce ground hum. I have Telefunken tape machine + other outboard connected to each other - when outboard runs without TF, = no hum, when only TF is connected to converters = no hum, but when OTB+TF is together = hum. Tried many power conditioneers, tried even connecting TF to other phase than OTB - no succes.

Guess what worked - wall outlet without ground pin. TF connected to that, everything to power conditioneer. Works great.
Old 12th September 2011
  #6
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Quote:
Originally Posted by Riccardo View Post
What do you mean with different timbres?
Low frequency hum? High frequency "whistle"? Tone sweep?
Could well be garbage in electrical the supply provided the earthing is ok. An isolation transformer is likely to help more than a conditioner albeit not exactly a cheap solution.
Hi Riccardo, thanks for reply, basically when I power up the K + H's there is a very low hum present (believe all powered monitors have this), this is very quiet, only can hear it with my ear next to the monitor. However, when this issue happens that hum changes in frequency it is still at a low frequency, the left monitor appears to be more prone to the issue and at a greater amplitude than the right monitor. When this hum/loop is present even disconnecting the monitors from all other devices and powering down such devices the issue remains, which leads me to believe it is power related. I do not have much knowledge of power conditioners or separating earthing etc, so any advice would be much appreciated, I have just looked at one of the SurgeX power conditioners today but I am a bit reluctant to pay that amount of money for something if its the wrong solution, thanks, Paul
Old 12th September 2011
  #7
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Verified Member
Unfortunately finding the culprit is usually a major pain. If i were you I would hook them up at a mate's place in another building/house to make sure it is not the speakers/amps themselves. Surge protection is always good but it won't cure the hum. If it is contaminated power supply or grounding or both the only cure I can see is an isolation transformer of some sort either standard or audio dedicated (more expensive). Ask around to see if any of your mates have one of those BT iso transformers from a few years back lying around in the flat.
First and foremost check that the issue isn't coming from the speakers themselves!


Quote:
Originally Posted by Temptation Music View Post
Hi Riccardo, thanks for reply, basically when I power up the K + H's there is a very low hum present (believe all powered monitors have this), this is very quiet, only can hear it with my ear next to the monitor. However, when this issue happens that hum changes in frequency it is still at a low frequency, the left monitor appears to be more prone to the issue and at a greater amplitude than the right monitor. When this hum/loop is present even disconnecting the monitors from all other devices and powering down such devices the issue remains, which leads me to believe it is power related. I do not have much knowledge of power conditioners or separating earthing etc, so any advice would be much appreciated, I have just looked at one of the SurgeX power conditioners today but I am a bit reluctant to pay that amount of money for something if its the wrong solution, thanks, Paul
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