Jump to content

Cheater Plugs to reduce ground loop hum


gbrlex

Recommended Posts

  • Replies 72
  • Created
  • Last Reply

Top Posters In This Topic

Sorry if my lame post was confusing,I really never recovered from my past ground loop hum with the Cayin amp and TAD preamp. Basically the Klipsch tech was a great help for me. I was told to use a cheater plug on the preamp and 2-baluns connected back to back between the tv and TV coax. At that the time magic boxes were still on back order and the 2-baluns did the same as the magic box.

Cheers,

Robert

Link to comment
Share on other sites

Craig,

"see its time for your meds again. I bet you read all this in a book !!

By the time the inter-connect melts down the entire piece of gear would

be junk. EVER HEAR OF A FUSE ?????? "

And tell me how much a fuse is going to do when the hot lead in the

equipment comes loose and hits the chassis completely bypass the fuse?

In a power amp the fuses will pass far more current then it would take

to burn up most interconnects ground connection. Once the ground

connection burns out the chassis is going to be floating live. Maybe

you don't care that this is a real possiblilty and that your advice

might kill someone or their child but I do.

It is plain and simple... there is a right way to do things and there is a wrong way. You are advocating the wrong way.

Don't get pissed at me for you being a hack.

Shawn

Link to comment
Share on other sites

Craig,

"see its time for your meds again. I bet you read all this in a book !! By the time the inter-connect melts down the entire piece of gear would be junk. EVER HEAR OF A FUSE ?????? "

And tell me how much a fuse is going to do when the hot lead in the equipment comes loose and hits the chassis completely bypass the fuse?

In a power amp the fuses will pass far more current then it would take to burn up most interconnects ground connection. Once the ground connection burns out the chassis is going to be floating live. Maybe you don't care that this is a real possiblilty and that your advice might kill someone or their child but I do.

It is plain and simple... there is a right way to do things and there is a wrong way. You are advocating the wrong way.

Don't get pissed at me for you being a hack.

Shawn

Shawn,

So if the hot lead hits the chassis on a ungrounded modern component that IS UL listed that is attached to a 3 Wire UL listed device what is going to happen? Same darn thing.

One more question....... how the heck is this hot lead going to fall off and hit the chassis? I sure hope the gear you and others around here use is built better then that. Pretty redicules what if there...

Alarmist crap......

Craig

Link to comment
Share on other sites

"..... how the heck is this hot lead going to fall off and hit the

chassis? I sure hope the gear you and others around here use is built

better then that. Pretty redicules what if there..."

It doesn't have to be that type of fault. It could be a capacitor

shorting out, or a transistor shorting, or a transformer

failing....etc...etc.... whatever... kaka occurs.

A piece of equipment with a safety ground may use the chassis as a

ground point for that sort of thing. And it is perfectly fine to do

that because if a fault occurs you end up shorting the AC directly to

the safety ground and end up popping the circuit breaker/blowing the

fuse.

Unless of course someone removes the safety ground with a cheater plug. (The name alone should give a clue to its use)

When the safety ground is left open then the AC will try to ground out

through the interconnects. Those interconnects aren't built to take any

sort of current. If you are lucky the fuse in the equipment will go

before the interconnect. If you aren't lucky the interconnect will act

like a fuse and the ground on it will burn out or it will burn

something in the other piece of equipment it is connected to. That will

leave the chassis of the equipment *HOT* and potentially lethal. All

because someone was too lazy to fix a ground loop the proper way and

not be a hack.

"So if the hot lead hits the chassis on a ungrounded modern component

that IS UL listed that is attached to a 3 Wire UL listed device what is

going to happen? Same darn thing."

In that situation yes it could be the same. Except that two wire

equipment usually uses much smaller gauge power cords so that they can

act as fuses for worse case situations. (Which ain't a great thing...

my friends apartment burned down in a case like this)

2 plug equipment also typically has floating grounds. IOW it doesn't

typically connect power ground to chassis/signal ground so a component

failure (cap., transistor..etc..) can't make the chassis hot. And

sometimes the power connection to the chassis is done through some form

of a fuse so that for signal levels it is grounded but if any real

amount of current passes through it the chassis won't go hot. And of

course a lot of 2 wire equipments chassis are plastic.

Shawn

Link to comment
Share on other sites

I got my Ground loop solved with a 17.00 ground loop lsolator from Radio shack..........

I had Time Warner Cable a couple of years ago with the digital cable

box. I had the ground loop issue, and tried the back-to-back

balun solution, and the isolator solution. Unfortunately, these

iterfered with the cable signal just enough so that I lost the digital cable channels

above 700, which happened to be all of the "digital music" channels.

Link to comment
Share on other sites

I could possibly trip and hurt myself going down to the shop today........I think I'll have a elevator installed........... no wait the power could go out while I'm in the elevator and I could die in there...... Well I guess it's just to dangerous to work.

Give me a break.

Craig

Link to comment
Share on other sites

"My house was built in the 50's and there is not a grounded receptacle in sight. Guess Rotel would not want me to use one of their amps. "

Actually you can... provided you use a cheater plug *properly*. Take a look at a cheater plug... you will see they *all* have a metal tab sticking up on them. That tag is connected to the safety ground on the 3 plug side of the cheater plug.

Connect a 16ga. wire (or thicker) from that tag and connect it to a good strong ground. (Water pipe, heater pipe, or drive your own ground rod...etc.) That will keep the safety ground intact for the amp.

This is what 'cheater plugs' really were built for. For using 3 lug equipment in homes built before safety grounds were required.

If a person has *really* bad ground problems you can actually do the same thing with all 3 prong equipment and tie the wires from each of the cheater plugs together on a bus bar and then ground that. That will star ground all the equipment and tie it to one point while keeping the safety grounds intact. If all the equipment is fed of the same circuit that is rarely need though. Esp. if all the equipment is fed from the same outlet using a power bar... the equipment basically star grounds itself there.

Often ground loops are caused from cable/satelite TV feeds. In those cases there are easier ways to deal with them then the above.

Shawn

Link to comment
Share on other sites

Be stupid in your own home then, don't give bad advice to others because you either don't know how or are to lazy to track down a ground loop and fix it properly.

Depending upon whoes numbers you go by typically 67,000 to 90,000 homes burn every year because of electrical problems. Killing anywhere from 400 to 2000 people and injuring several thousand more. 1 in 3 fires is electrical in nature. IOW... don't screw around with electrical safety....

100 milliamps can kill. That is 1/10 of 1 amp or 1/150 of the available current from the AC socket in your wall. Some accounts say 15ma can kill.

IOW, every amp you have touched has the potential to kill someone. It is good to see you care so much about electrical safety considering you send out high voltage equipment to peoples homes.... with far more then 100ma, let alone 15ma, flowing through it.

Pick up *any* book on electrical safety and they will *all* talk about not defeating safety grounds from equipment. For example anyone can go down to Home Depot and take a look at 'Wiring Simplified.' Chapter 7 is entitled 'Grounding for Safety.'

Gee... I wonder what that is talking about???

Every grounded tool you have ever bought in your 'past life' would have had warnings on it to not disable the safety ground. All your safety grounded audio equipment likely had a page right up near the front of the manual labeled "Important Safety Instructions" specifically saying not to disable the safety ground.

OHSA, UL and everybody else says not to disable safety grounds on equipment. There are reasons all building codes specify ground plugs in homes today....etc...etc.... EEs and electricians understand this... you... not so much...

Do it right, or be a hack... your choice.

You don't get to hear from the fools that learned the hard way.

Shawn

(and this is saying nothing about the elimination of any surge suppresion, static or lighting suppresion protection that removing the ground plug also takes away from you. Hint if you plug a surge suppresor into an ungrounded outlet/cheater plug for the vast majority of them if a surge occurs on the line they can't do *squat* about it. Ditto in the winter walking up to your equipment and zapping it accidentally. Without a safety ground that zap is going to travel through your inter-connected equipment trying to get to actual ground and possibly damaging something along the way.)

Link to comment
Share on other sites

"What would it take to set a ground rod type ground?"

You may already have one if you had cable installed, it is code in some places. Ditto for an outdoor antenna they must be grounded to avoid static build up from the wind.

If you don't have one they sell ground rods at Home Depot. You want a brass rod. They typically are driven 6' or more down.... it isn't fun doing that by hand with a sledge. The electrical department will also have the needed clamps to connect the ground wire to it and will have the dielectric grease to protect that connection. Ground wire may be unshielded and it is usually very thick....2 or 4 ga for example. You would then run that to where you wanted to go. The entry point into the house is where the ground rod should be. One way to distribute the ground easier indoors is to attach the cable to copper plumbing in the house then ground indoors to the plumbing. Use a water line only for this.... don't use a gas line as a ground.

If you are going to do this check with your local building code though. They might have some slight difference from this but this is basically how it is done. It may not allow using internal plumbing for example or whatever. Your town hall should be able to give you the electrical code for your area.

Shawn

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...