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Cheap fix on Ground Loop


derrickdj1

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His statement in the 3rd sentence of "To do this you will need to ‘unground’ the offending piece of equipment." is misleading. Neutral/Return & Ground are bonded to the same point creating multiple paths to ground, in case there is a failure in one of the paths. Having two wires does not "unground" the equipment. It's impossible for A/C voltage to even work if there is no path to ground. 

 

He kinda goes into showing he understands this in the last paragraph, by explaining how he has solved his own ground loop problems. The statements are misleading how he pairs them together.

Edited by Beechnut
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Timely comments from Paul McGowan, founder and CEO of PS Audio 

 

http://www.psaudio.com/pauls-posts/if-doing-the-right-thing-fails/

 

Seems to be an honest and forthright apprisal.

His statement in the 3rd sentence of [/size]"To do this you will need to ‘unground’ the offending piece of equipment." is misleading. Neutral/Return & Ground are bonded to the same point creating multiple paths to ground, in case there is a failure in one of the paths. Having two wires does not "unground" the equipment. It's impossible for A/C voltage to even work if there is no path to ground. [/size]

 

He kinda goes into showing he understands this in the last paragraph, by explaining how he has solved his own ground loop problems. The statements are misleading how he pairs them together.[/size]

What's misleading in terms of this conversation is that he sells equipment that uses XLR cables, which yeah, does ground to the other components in the rack, that's why he can say what he did in the last sentence of the last paragraph. It's all still grounded.

Edited by MetropolisLakeOutfitters
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I spent two years of frustration attempting to rid my system of a ground loop. The cable guy suggested a cheater plug and it completely eliminated it. If the other things that I spent money on worked, I would not employ this method; however, every other method either did not work, or only worked to some extent. 

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Timely comments from Paul McGowan, founder and CEO of PS Audio

http://www.psaudio.com/pauls-posts/if-doing-the-right-thing-fails/

Seems to be an honest and forthright apprisal.

His statement in the 3rd sentence of [/size]"To do this you will need to ‘unground’ the offending piece of equipment." is misleading. Neutral/Return & Ground are bonded to the same point creating multiple paths to ground, in case there is a failure in one of the paths. Having two wires does not "unground" the equipment. It's impossible for A/C voltage to even work if there is no path to ground. [/size]

He kinda goes into showing he understands this in the last paragraph, by explaining how he has solved his own ground loop problems. The statements are misleading how he pairs them together.[/size]

What's misleading in terms of this conversation is that he sells equipment that uses XLR cables, which yeah, does ground to the other components in the rack, that's why he can say what he did in the last sentence of the last paragraph. It's all still grounded.

RCA cables pass ground from one device to the next also.....

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I'm sorry and this is only my HO but you cannot get a pair (or 1 for that matter) of high quality (good freq response down to 20Hz and at low distortion levels) audio transformers for 6 bucks.

 

I measured the distortion level at near subwoofer and MLP today.  Here are the numbers:

 

10Hz              less than 1 meter to speaker  25%                  MLP    12.67%

 

20Hz                                                             4.59%                            8.84%

 

50Hz                                                            1.23%                             0.47%

 

100Hz                                                          0.67%                             1.23% 

 

The subs are tuned to around 21 Hz and the 10 Hz distortion level of 25/12.67% is not unexpected since I am not trying to reproduce those frequencies. The 10 Hz measure was taken with one of the vented subs. The 100 Hz distortion number of 0.67 and 1.23% are opposite of all the other reading since the close mic measured lower.  This is also not unusual since the system is XO at 50 Hz.  The 100 Hz measure represents the mains and sub at the MLP.  The distortion readings are very good for the system in the working range for the subwoofers using the ground loop isolator.  For 20 Hz and above the system wood get a very good rating from database.com CEA standards for subwoofers.  Distortion figures derived from Dayton Omnimic.

 

To be clear. In my original post I was not referring to or concerned about the levels or distortion coming out of the speakers, I'm talking about the transformer itself. If you put a 20Hz signal in at +20dBV(or even 0dBV)@0.1%THD the output will not be the same with a $2 transformer. Now can you hear 8.84% distortion at 20 Hz is an entirely different question.

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Hard to believe how many folks around here are alarmists....I still like to see one documented situation where a consumer using stereo equipment with all but one device grounded via the wall was killed or even injured in anyway...seems like you could find some real proof of this extreme danger...

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I'm a lot more concerned about the safety of all the piece of junk "made in China" plastic boxes that get plugged in all over the house.  Have you ever gone around your house and counted all the wall warts and different devices you have plugged in??  One of them decides to self destruct and you could lose your house.  Twice in the last 12 years or so I've unplugged things that were either melting or starting to stink like burning electronics.  Another time it was a power strip that was getting hot without anything even plugged in.   Luckily, I was here to catch it all!  I keep as much unplugged as possible these days.

 

Seems to me with tube amps new or old you just have to use a little sense.  I try not to leave them unattended, keep the kids away,  and don't give myself a path to ground if doing something with them like adjusting the bias.  With kids, I worry most about them knocking or breaking a tube and coming into contact with a live circuit.  I think I have instilled an appropriate amount of fear in them.

 

I have to take a short electrical safety course every year for work.  I'm surprised at some of the myths that still seem popular... such as electricity following the path of least resistance.  Electricity follows ALL paths!  Another thing pounded into our heads is that GFCI should always be used on circuits with power tools and extension cords.  They also make the point of showing situations where GFCI will not protect you.  Next time the course comes up I will share some of it here for anyone interested.  

 

All that said... yes, I use a few cheater plugs.  

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All that said... yes, I use a few cheater plugs.

Man you sure you will live long enough to share the information from the electrical safety course ;)

 

 

Maybe... maybe not.  I installed them on a power strip in my shower so I can turn on some tunes while taking a shower  :o

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All that said... yes, I use a few cheater plugs.

Man you sure you will live long enough to share the information from the electrical safety course ;)

 

Maybe... maybe not.  I installed them on a power strip in my shower so I can turn on some tunes while taking a shower  :o

SHOCKING!

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