Cheater Plugs to reduce ground loop hum

[NOSValves]

Lightning hit me in 1985, since then I only like horn speakers....

Awesome!

[NOSValves]

" I wonder if anyone has ever had this happen?"

That is why safety grounds are now on a lot of equipment compared to fifty years ago.

As far as having components fail and ground out the hot... yup.. it has happened to me on a big SS amp that had failures in its PS. But it was safety grounded and the damage ended with the amp.

I'm sure you of all people wouldn't claim that amps/components last forever and failures never happen. If they did there were be no need for restorations....

"All of my equipment whether 3 wire grounded or not I can measure from the outer chassis case or a screw on the outer case when the case is plastic to the hot side of the AC plug and get 117 VAC which means they are all earth grounded together."

Which means nothing. Go put 15 amps through them and see how well it diverts that much current to ground. Also see if that current flow through the equipment does any additional damage to the interconnect systems..

"To accomplish what you suggest almost everyone on this forum would have to get out a soldering iron and modify at least some of there gear (mostly sources and video equipment)."

BS. I am *certain* I have a dramatically more complex interconnected system then you do. I don't have ground loops.

Just because you can't figure out how to get rid of ground loops (or avoid them in the first place) without resorting to hacks doesn't mean that holds for everyone.

" I say it's VERY VERY unlikely to EVER happen. Kind of like getting struck by lightening."

Lightening struck about 25 feet away from me when I lived in OK and started a small fire in the yard it hit. I was riding by in a car and saw it happen.

In a different house/state lightning struck the cable feed or somewhere nearby (which was underground) into the house and blew up the cable box and the VCR (which was plugged into the cable box) when I was literally walking over to change the channel. The other equipment connected to the VCR was fine.

Years later in the same place we had another lightning strike somewhere nearby again and burnt up one of the hot feeds from the electric company (again underground in conduit) to the house. Half the circuits in the house worked until that got replaced.

So don't talk to me about lightening.

And speaking of which a safety ground can also help to limit collateral damage for things like lightening strikes to. And without a safety ground the vast majority of surge suppressors out there can't do anything. The way most of those units is literally by shorting a surge to ground. Without a ground they can't short the surge out... so it passes right through the surge suppressor and onto your equipment.

There are a few suppressors that don't work the same way. They act more like a low pass filter on the AC line. Surges by their very nature are transients (high high frequency spikes)... if you in effect put a low pass crossover in the AC it rolls off the transient. This also works well for removing noise on the AC. They also try to store the energy in big capacitors and then slowly drain it out into the neutral line.

Everyday I work around a couple of power systems with enough capacity to run a house with 100amp service off battery power for around 12-14 hours or longer if the load is lower. You screw around near those systems and you die. The AC outlet you plug your equipment into can kill you just as quick.

Shawn

Shawn,

You really need to relax dude. Maybe your working to close to the electricity all day it's got you all charged up.

Regardless of what I say you keep skimming over the fact that almost everyone on this forum has a system that wouldn't pass your electrical guide lines. The point of being able to measure 117V from the chassis to hot lead AC of a none 3 wire component is that IT WILL NOT PASS YOUR SAFETY TEST even though it is a UL listed component. If this component had a failure as you suggest and the magical hot AC lead fell off and connected to the chassis ground it would fry the inter connect as you suggest (more probable it will fry a trace on its circuit board before the inter connect). The only way for someone to pass your test is to modify all there equipment to a 3 wire system. All to protect for a one in a million chance that the hot AC wire is going to magically fall off and solidly connect to the chassis.

Enough said I'm done..... this circle will never end. No one is wrong here.

Craig

[dragonfyr]

So let me see if I have this right...

...It's OK for me to use my hairdryer in the shower since it has a 3 pronged plug......?

[sfogg]

"The point of being able to measure 117V from the chassis to hot lead AC of a none 3 wire component "

Unplug the equipment from everything else and retest.

"The only way for someone to pass your test is to modify all there equipment to a 3 wire system."

No it isn't. I am not saying to modify two wire equipment. The

manufacturer of the 2 wire equipment built it knowing it was two wire

equipment. It is built differently then if it was three wire. I already

stated that earlier in this thread. Read better.

The manufacturer of three wire equipment built their equipment

expecting for the safety ground to be there. Defeating that is dumb.

Plain and simple.

Esp. when you consider defeating safety grounds.. they can *sometimes*

help protect against failures in 2 wire equipment. But the longer you

string together equipment with safety grounds the more likely that

can't happen. And you could end up with numerous chassis with hot.

"All to protect for a one in a million chance that the hot AC wire is

going to magically fall off and solidly connect to the chassis. "

You don't read very well do you. Any sort of failure that connects hot

to chassis can cause the problem. Component failures, a five year old

spilling a juice box on the equipment.. anything.

" Maybe your working to close to the electricity all day it's got you all charged up. "

Or maybe I simply understand the dangers better then you do.

Like I have stated... every safety organization out there has said not

to remove safety grounds from equipment. There is a reason for that.

That is why electricians and electrical engineers make these sorts of

decisions.

Shawn

[NOSValves]

Shawn,

Why would you not test a piece of gear AS IT IS USED IN A SYSTEM what would be the point?

The issue that I'm trying to portray here is not whether or not to remove safety grounds. The issue I'm calling you on is that every 2 wire component has done it for you. My point is that your theory says there not safe. But then there still UL listed, so UL must be wrong and Shawn is right.

The fact that the 2 wire components are built different means nothing the catastrophic mystery failure you speak of would end in the same results. BECAUSE THE GEAR IS ATTACHED WHEN IN USE.

So from the "Shawn handbook on Audio/Video system hook up" to pass your test those 2 wire pieces of gear would indeed have to be modified.

What you can't seem to grasp here is I understand 100% what your saying and have never said you were wrong in anyway. I am saying worrying about such ridicules things is plain Anal. DO you get my point.......... God I hope so.

Craig

PS

If you would read better you could go back to my innitial post where I stated "While there is some small margin of safety in having gear grounded its very small" I never said there wasn't a better margin of safety in having 3 wire gear grounded. Why the hell else would I install 3 wire IEC's on all the amps I sell Daaaaaaaaaaa

[sfogg]

"Why would you not test a piece of gear AS IT IS USED IN A SYSTEM what would be the point?"

Because then you might learn that the two wire equipment is built

different. Power ground is typically kept separate from chassis ground

as already mentioned numerous times. The only reason you are seeing

chassis/power ground connected in the two wire equipment is because it

is connecting elsewhere though connections that aren't built for

current.

If a component fails (cap, transistor...etc..etc..) in a piece of

equipment built, properly, without a safety ground the AC won't go to

chassis.

In a three wire piece of equipment if a component fails the AC can go to chassis.

"My point is that your theory says there not safe. But then there still UL listed, so UL must be wrong and Shawn is right."

Get this through your head... THE UL SAYS REMOVING SAFETY GROUNDS IS NOT SAFE.

It isn't what I am saying against the UL, it is you. Also against OHSA

recommendations... and every other electrical safety standard there is.

Shawn

[sfogg]

"..It's OK for me to use my hairdryer in the shower since it has a 3 pronged plug......?"

Right, 'cause anyone has made any comments ever remotely along those lines.

Tell you what though... your chances of living through the attempt are

better if everything was built to current safety standards

(grounded hairdryer, GFI outlets in a bathroom) compared against having a disabled ground and no GFI circuit.

Shawn

[Erik Mandaville]

Power ground on my amps is by way of a short piece of wire, froum ground lug on IEC to bare metal chassis under a lock washer. It's kept separate from circuit ground for reasons mentioned above. For my part, I'm re-thinking the human error element. I had mentioned double grounding the input/driver star ground on one amp at two different points on the chassis. If I can make that mistake, I'm capable of doing something else that could yank me off the stage for keeps.

This is an important!

Erik

[NOSValves]

"National Alarmist day" as turned into "National Alarmist weekend"

[fini]

Eric,

Count me as another member thrilled to see 1.) You're back posting on the forum and 2.) You did not get washed away into the sea! BTW, how did you fare lovely Rita's water rage?

[Erik Mandaville]

Craig:

It's being safe. As I said, I have been lifting the grounds on a couple of components, as well. If the chance for greater personal and/or customer safety presents itself, it might be worthwhile to consider some of the safer options. Even the best component can have parts that may fail due to manufacturing defects, poor or careless workmanship, and so forth. I think that's the point here. If being an alarmist can save a life (literally!), I really don't mind falling within the ranks of the alarmist infantry. There's some old adage that has to do with this subject..........

Fini: Nice of you to say that. I just needed a break, I think. Thanks too for your thoughts about angry Rita! We made a last ditch effort to evacuate, with me thinking we would be ok on some back roads I know about that go West. It turned out that half a million other families knew the same roads. That number is really not so far fetched, either. With four dogs in the back, two chinchillas in a little cage, some emergency food and water, we decided it would be safer to go back home and hunker down than get stranded on a freeway, out of gas, out of water, out of food, with 6 precious animals overheating. There were some very serious problems. We turned around in order to not get stuck in that. Some people were not so lucky, though.....

Erik

[gbrlex]

Thanks to everyone for all the information and thoughts on cheater plugs. I was able to correct the hum without using a cheater plug.

I attached a wire to the ground screw on my adcom ac enhancer and touched each piece of my equipment with the opposite end of the wire. The problem turned out to be my dvd player. I scraped off a little paint around a screw for the cover in order to get a good ground and the hum was gone. If you try this, make sure you touch the bare wire to bare metal. On my first attempt, I touched the bare wire to the painted surfaces of the equipment and nothing happen to the hum.

Again, thanks to all.

[michael hurd]

Good to see that you have gotten this resolved without the need to lift a safety ground. I have run into this problem in the past, by grounding all the equipment together, the problem disappeared.