Another cheater plug thread

Something not mentioned is the sonic issues related to lifting a ground.

The problem is a ground loop, you lift the ground and no more hum. This is caused by the fact that some part of the signal chain (amp, preamp) is improperly wired.

For example if the chassis and circuit ground are the same thing, that unit will be prone to ground loop issues. Now to pass UL and CE (in fact any electrical code worldwide) the chassis has to be grounded. The issue is how to deal with the circuit ground if the chassis is grounded, and not have a ground loop.

The solution is simple but you would be utterly amazed at how many companies have not sorted this out! All that is needed is the circuit ground 'float' within the chassis, with all ground points like RCA connectors and the like isolated from the chassis. Then a moderate resistance is used between the chassis and circuit ground. This floats the circuit ground at chassis potential (electrical ground).

The added benefit is that now the chassis shields the circuit without injecting noise, something that results in better sound due to 'blacker backgrounds'.

So, IMO/IME its worth it to get equipment with bugs like this fixed! If done, you never worry about grounds again, and you don't have to mess with exotic (kooky) grounding schemes like a rod in the garden or some messed up stuff that is a recipe for trouble.

I know that may draw some criticism but honestly, get the equipment fixed and you will find out what I am talking about.

I would think that some return to ground is necessary otherwise system noise would travel from box to box. For instance noise induced in the shield has to find return to ground and it is far better to find direct path instead of currents traveling on ground wire of IC (causing voltage drops that appear as signal) to another box that is "closer" to ground even if everything is floating. Floating might also be a disaster in case of static discharge to connector ground since current will go thru all available paths (including signal path electronics) to find return, instead of quick return to local ground. I would use high voltage capacitor about 0.01uF/1kV possibly with 100k-1M resistor in parallel between signal and chassis ground possibly close to input connectors. Hard wired connection (like in IBM PC) is good when we have only one box but otherwise makes ground loops or cause large current between boxes plugged into different outlets when connected together.

I strongly agree with Atmasphere and some others. Fix the problem, don't cover it up and cross your fingers hoping for the best. Find the cause of the ground loop (it is fairly simple but tedious to do this), and either fix or replace the faulty piece of equipment. Do not use a cheater plug. This is lazy and seriously stupid. All the more reason to audition equipment in your home/system before you purchase it. If a ground loop occurs during auditioning, then find the culprit and remove it or fix it.

Also, anyone that recommends to lift the ground, use a cheater plug, not use seat belts and other dangerous things, are not your friends and are not looking out for your best interest.

enjoy

ATTENTION- Anyone with Dynaco, ARC, McIntosh, Marantz or Conrad Johnson(tubed components), that lack a grounded power cord: Keeping/using that equipment is dangerous and not in your best interest. Send it to ME, IMMEDIATELY(I'm your friend and will take all the risks)!

Hi Minorl, Great advise. You sound like a very knowlegable person so perhaps you could answer a question I have.

I have an amp which is grounded properly driven by a pre-amp which is grounded properly. When I plug in a CDP it creates a ground loop and I get a hum thru the speakers. When I put a cheater plug on the end of the CDP power cord the hum goes away.

What risk to I incur in operating the system with this cheater plug in place? Why is that so? So I better understand, please create a situation where the risk you describe will be encountered. Please take it beyond electrical theory. If you can back it up by referring to an actual occurance that would be better yet.

In anticipation of the thoughtful reply I will receive, thanks. Perhaps I'm not lazy or seriously stupid, just a little bit ignorant. :-)