Hum & Buzz

dholmes

Ive had a problem with hum-buzz in my system for awhile now & finally found what it is, my projector while plugged in to the outlet causes the noise. I first thought it was ground fault circuit that the projector was plugged into so I took out the ground fault.But it still had noise in my system,the projector works fine no pq problems. I think if I could ground the projector to the rest of the equipment that would solve the noise. How would I ground a plastic projector to the ground on my equipment? thanks ps the projector & the audio are on different circuits

Dennis Gardner

Try "lifting" the ground first. What your are experiencing is a ground loop where 2 grounds are being found for your equipment since more than a single outlet is used. This happens more with projectors than TVs since the PJs are in different parts of the room. You video may improve as a result too.

To "lift" ground, put one of those old 3 prong to 2 prong adaptors on the projector. I suggest lifting instead of finding "common ground" because it is usually prohibitive to plug all your equipment into the same outlet due to the distances unless you rewire.

dholmes

Thanks I have a surge supp. on the projector that plugs into the outlet like some people use for a sub its a Monster surge. Are you talking about a cheater plug?

Dennis Gardner

dholmes wrote:

Thanks I have a surge supp. on the projector that plugs into the outlet like some people use for a sub its a Monster surge. Are you talking about a cheater plug?

Yep...........the surge protector is still being grounded in a different place than your other equipment and that itself is finding the buzz. The buzz is probably working its way back through the video cabling, to your audio gear.

dholmes

Thanks again! I would like to keep the surge supp. would I plug the cheater plug into the surge supp then plug the projector into the cheater plug. The supp has a ground screw the I could use on the cheater plug.

Dennis Gardner

Where you use the cheater isn't important and is your choice. Don't use the ground wire at all. What you are trying to get rid of is having 2 grounds. I suggested the cheater as opposed to yanking the ground wire out of your power plug since you may want it grounded later or to resell.

If you aren't comfortable with ungrounded usage, then you will have to plug all your equipment in the same outlet or at least on the same circuit.

Dennis Gardner

Using your audio/video equipment without a ground is a common practice. Many of your pieces don't even come with the 3 prong plug since bad grounds cause more problems than they solve. No DVD/CD player of mine has a ground.

dholmes

So your saying to just plug the cheater plug into the surge supp. & dont use the ground part of the cheater plug?

Dennis Gardner

dholmes wrote:

So your saying to just plug the cheater plug into the surge supp. & dont use the ground part of the cheater plug?

That should work.

dholmes

Thanks for all your help, if this doesnt work I think if I attach a wire to the mount on my projector & ground it to my eq.

Dennis Gardner

Getting rid of the "noisy" ground is the answer. If it only happens when the PJ is hooked in line, then the PJ ground is the problem.

dholmes

The buzz-hum stop by using the cheater plug on the projector. When I turned everything on it was silent, but when I went to shut things down it was back! The projector didnt cause it this time, I dont know where its coming from! One thing I did a while back was ground my pre-pro with a wire to my Panamax surge supp which has a grounding screw on it & that helped.when you touch the groud wire to the Panamax it gets quieter, when you unhook the wire it get louder. Its a ground loop problem I believe,theres no cable, just dvd watching in my ht.Is there anything else Im missing that might help?? thanks again

dholmes

Also Ive read several things on hum, still cant figure what it is!! My electrical ground is okay, its the double ground with 2 8ft grounding rods. thanks

Dennis Gardner

Try using the cheater on the Panamax. This would lift ground from your whole system eliminating the chance that "ground" is your problem as long as every component goes through it.

dholmes

D.Gardner, thanks for all your help! I thought it solved the problem when I hooked up the cheater to the projector, but it came back. I know its sounds strange that it was gone & it came back. Ill try the cheater plugs on the Panamax.

Dennis Gardner

I know this will sound strange, but water your ground spikes outside your house. Sometimes they are located under an eve, that may get sunshine but rarely get any direct water contact and this can cause them to loose continuity with the soil when the ground cracks around them. I wouldn't think that this is a issue in Kentucky, but where I live, I see it regularly.

dholmes

When I use the cheater plug on the Panamax should I connect the ground screw on the plug to the outlet, or would that defeat the purpose/ Also the grounding rods outside are 9ft in the earth separated 8 ft from each other, that was the newer code around here. thanks

MLZ

When I had a similar problem, the ground loop was caused by my TV cable (for some reason it just started about 6 months after I got my HT system), the "cheater" plug did not work, I was able to put a device on the coax which removed the hum, but picture quality degraded, so an electrician friend swapped out my electric receptacle (my house was built & wired in 1930) and everything worked.

dholmes

Ive check all my plugs that have there okay, is it dangerous to eliminate the 3rd prong on a piece of equiment? A cheater plug that D Gardner was talking about was going to lift the ground in other words Dont connect the ground lug on the cheater plug to the outlet.

janmike

I had the same problem and it was my CATV. I had the tech check the coax coming into the house and put on a new ground. Problem solved.

dholmes

My system has no catv in it, I just have dvd for my ht watching. So catv is not a issue. thanks

Dennis Gardner

Something to try when you have a "helper" and a half hour to waste...........

Turn on your system to get the buzz and go through your house either tripping breakers or unplugging appliances until you find the culprit causing the buzz. Refrigerators/freezers, ceiling fans, dimmer switches on lighting, microwave ovens, sprinkler controls, etc. anything with a motor or variable speed control are noise makers.

Good luck

dholmes

Thanks, Ill try that, also how do you "lift" ground without using a cheater plug? Most of the things Ive read on the internet says dont use cheater plugs! The buzz-hum was reduced when I used a piece of wire & connected it to a screw on my pre-pro & then connected to the ground screw on the Panamax. It sounds like most of the problem is with the pre-pro & amp.

Dennis Gardner

You are too worried about your ground wire. My PS Audio power cables that I use for my gear actually have a removeable ground pin just for this issue. Unless you are on a wet garage or patio slab, you should have no problem.

dholmes

Thanks, so if I use a cheater plug & want to lift the ground DONT connect the screw on the cheater plug & if I want to ground use the screw on the cheater plug to the outlet.Yes I know the 3 prong is for when your wet & plug in a piece of equiment,the internet advised not to. Ill try several things that you said to & I think Ill use some wire & daisey chain the equiment to the Panamax.What makes all this a problem is that the hum-buzz comes & goes. thanks again!!

Dennis Gardner

If it is coming and going, I bet it is an appliance causing it. Probably one that has the ground prong removed....

dholmes

Thanks for answering all my pain in the a$$ questions! When I get home Wed Ill try the unplug method. So the lifting of a ground is eliminating the 3rd prong?

Dennis Gardner

dholmes wrote:

So the lifting of a ground is eliminating the 3rd prong?

Simple as that, and pretty much all you can do unless you are willing to run dedicated circuits to your panel just for your HT.

dholmes

Well thats what I did, 3 dedicated 20 amp outlets.