Ground loop with new A51

[mikepinkerton]

So I hooked up my brand new A51 (thanks tduski!) and immediately got a ground loop hum. Sigh! After about 20 minutes of playing with cables and outlets and plugging and unplugging gear I read the manual (shock!) and found that setting the "ground" switch to "lift" fixed all my problems.

So, um, ok, what exactly does "lift" mean? Does it mean that I really need to fix something in my house wiring and this is a temporary fix? Should I try to get the switch back to normal?

Here's what I get on normal:
- With the speakers connected and no input connections, no hum.
- Connect any input, hum on that speaker.
- Unplug my entire HT from power (so no unit gets power except amp), still hum.
- Move amp power to a separate, dedicated circuit, still hum.

I have a sat -> sat rcvr -> rcvr -> amp connection, but i figured with the power totally off on both rcvrs that would cause that to go away. Perhaps not, I'm no electrician Should I try removing the sat connection from the wall and see if it all goes away?

Do I need to take action to fix this, or should I just leave it be with "lift" set? Thanks!
-Mike

[Chris D]

I think you're set with the ground lifted. Other option would be to use a "cheater plug" that would eliminate the grounding prong from the plug going into the wall outlet. I too got a ground loop hum with my A51, A21, and C1. Using the lift on the A21 and A51 fixed it. (I still have a very slight hum if you put your ears up to the speakers--probably just because they're sensitive Klipsches)

[mikepinkerton]

I've traced it down to my satellite. Removing that from the system makes the hum go away. It's still quite audible even with "lift" on so I'm going to try to make a ground isolator for the sat line using some 75/300ohm converters.

Hopefully that will fix it, I couldn't stop thinking about it all night long. Finally get the new amp and all I hear is hummmmmmmmmmmmmmm even when I close my eyes

-Mike

[brucek]

I'm going to try to make a ground isolator for the sat line using some 75/300ohm converters.

Mike - I'm afraid that's a bad idea. :roll:

Unlike cable, satellite uses the RG6 coaxial feed to pass DC voltage to your antenna horn amplifier. A ground loop isolator will block the DC and the feed horn amplifier won't work.

A ground lift switch is not the same as a cheater plug. A cheater plug opens the safety ground and is a dangerous fix unless strictly controlled.

Usually a proper ground lift switch on an amplifier simply places a small resistance between safety ground and DC ground of the DC power supply. This resistance is usually enough to stop the loop hum. The safety ground is still connected to the case of your equipment though, which leaves you with a safe situation.

You can ensure this is so by checking the resistance with a meter between your case and the ground screw on a wall receptacle with the ground lift enabled.

brucek

[mikepinkerton]

Well, drat. I still get some hum even with the Lift switch. What are my options?

Someone suggested using a 12ga wire to connect the ground on the amp to the chassis of the sat rcvr to unify the grounds. Thoughts?

-Mike

[brucek]

You have a potential difference between the house safety ground and the satellite ground.

This can occur for several reasons. Either the satellite installer didn't run the outside RG6 through grounding blocks or they didn't ground the blocks properly to earth with a rod and then bond the rod to the house system at its common point.

Check this out first.

[mikepinkerton]

The cheater plug works (whew!!). I read on other forums that linking the two chassis together (sat box and A51) with a 12ga wire will also fix it, and lo and behold it does!

Is this safe? I'm no elec engineer (obviously) but is this a valid solution to the problem or does it short out some protection? Looking for a safe solution (ie, not cheater plug) until I get get my sat installer out (may take a looooong time).

Thanks!
-Mike

[brucek]

Is this safe?

The cheater plug is not safe, but the bonding wire between the two chassis is a safe solution if it works. Glad you were successful.. :T

[mikepinkerton]

Yay! Yeah, i know about the cheater plug. I just wanted to make sure that it did work and for $0.69 at Lowes, why not try it? Convinced me 100% that the hum wasn't a defective amp. I'll pay that $ any day for that amount of relief

-Mike

[glgluxy]

Details Please.

I know this is an old thread, but I am having the same issue with my A51 (except it CATV instead of Sat).

How do you link the two chassis's ground? Do you just tape a wire to both chassis? Thank's in advance for your help.

[mikepinkerton]

Since you're on CATV, you can just get a decoupler (for about $10) and that will do the trick.

My solution was to take a 12ga speaker wire, strip the ends, and wrap an end under a screw on the SAT box and the other end around a screw on the top of the A51. No muss, no fuss, and free

Hope that helps
-Mike

[glgluxy]

Thanks Mike.

I actually tried a decoupler, but I lost all the sound on my digital and HDTV channels. I think the cable signal coming into my house may be weak. Before I called those jokers to mess with my stuff, I wanted to give this a try.

[Marshal]

Don't use cheap plastic cheater plugs! Buy PS Audio power cords with removable ground pin.

[mikepinkerton]

I think better advice would be to not attempt in any way to defeat the ground of this very powerful electronic device. I only suggested a cheater plug to verify the problem.

-Mike

[Marshal]

If you use power line conditioner that is grounded then there is no risk. And what if it is not possible to fix grounding problem at all? Should he return amplifier back to the dealer? And what is Parasound explanation on insisting on 3-prong power cord if they know that many people can encounter grounding problem in their systems? Is it so hard to internally rewire amp instead of insisting on external ground? This is Parasound's fault and they should have fixed it long time ago not to blame customers for real life problems.

[Peter Nielsen]

This is Parasound's fault and they should have fixed it long time ago not to blame customers for real life problems.

:wtf: What on earth are you talking about? Parasound amps DO have a "ground lift" switch that lets you "fix" the problem. However, as we all know, the amps should preferably be grounded because of all the exposed metal parts. The best solution for a ground loop is to locate the problem of the interference and fix it at its source instead of being lazy and just lift the ground.

Please explain why you mean a ground loop is Parasounds fault. They already provided the ground lift switch as a decent workaround. How can it be their problem when the problem is caused by other gear??? :scratchhead:

The only true remedy is to fix the source of the problem. The source of a ground loop problem is a piece of gear that is causing a difference in potential and thus causing a ground loop. AFAIK, Parasound does not manufacture any gear that can cause this to happen. The problem is in gear manufactured by a third party (usually the VCR or the Cable box that is hooked up to a cable connection that is not properly grounded and is causing a difference in potential and thus running current through the apparatus).

Peter

[Kingdaddy]

Easy possible fix for Sat ground loops is to remove the ground wire from the dish and see if it goes away, for cable you need something like a differential amp to shunt the noise away from the signal ground. I've delt with both of these issues and it has nothing to do with the amp.

[nicholtl]

Pete, what you said about Parasound not making any gear that has a difference in potential makes sense, but what happened to me causes me to wonder...

I connected ONLY my C2, A51, and A21 to my PS Audio P1000 Powerplant, and got a ground loop hum. All my other equipment was not even plugged into the wall. What I discovered was that my C2 was causing this hum, and I was able to solve the problem by removing the ground pin from the PS Audio powercable I was using with it. Do you know why this happened?

[Peter Nielsen]

Pete, what you said about Parasound not making any gear that has a difference in potential makes sense, but what happened to me causes me to wonder...

I connected ONLY my C2, A51, and A21 to my PS Audio P1000 Powerplant, and got a ground loop hum. All my other equipment was not even plugged into the wall. What I discovered was that my C2 was causing this hum, and I was able to solve the problem by removing the ground pin from the PS Audio powercable I was using with it. Do you know why this happened?

OUCH! That sounds like you may have a current leak somewhere. This should NOT happen. Does this also happen if you take out the powerplant and plug everything in a power strip and plug the strip directly into the wall?

Hmmm... A wild guess is that a bad ground could cause this problem too! Your outlet may possibly be wired inappropriately.

Peter

[nicholtl]

Ohh...hmm...well I DID install PS Audio Powerports in both my wall duplex receptacles...and the only way I could ground the ground wire was to physically make it touch the metal box in which the outlet is installed. Perhaps this could be the cause. But since I've defeated the ground loop now anyways, does it matter? It's not as if I'm getting less-than-potential sound quality?

[Peter Nielsen]

Ohh...hmm...well I DID install PS Audio Powerports in both my wall duplex receptacles...and the only way I could ground the ground wire was to physically make it touch the metal box in which the outlet is installed. Perhaps this could be the cause. But since I've defeated the ground loop now anyways, does it matter? It's not as if I'm getting less-than-potential sound quality?

Removing the grounding generally has no negative effects on the sound. However, in the unlikely event that something should go wrong with one of your units, causing a live wire to touch the chassis metal parts, then all your equipment may become electrified with 120V and be a death trap. That's really the major reason for using the ground wire in the first place. (This is also the reason why cheater plugs are illegal for some applications, especially with outdoor equipment where water could cause a short between the chassis and the live wire).

If the outlet is not properly grounded with a DEDICATED third ground wire that loops back all the way to the main fuse box, it will kind of defeat the purpose, so to improve your situation you would really have to get those outlets wired properly. Otherwise, I'd just forget it and leave it like it is :T

Peter

[nicholtl]

Cool, thanks for all the help Pete. You rock! I think I'll just leave it as is for now, and if I ever feel the urge to in the future, call an electrician.

[Marshal]

What on earth are you talking about? Parasound amps DO have a "ground lift" switch that lets you "fix" the problem.

Many people noted that lifting ground doesn't help at all.

The best solution for a ground loop is to locate the problem of the interference and fix it at its source instead of being lazy and just lift the ground.

Since this problem is only occurring with one particular brand or even one model then manufacturer should fix it this not customers.

How can it be their problem when the problem is caused by other gear???

Buzz coming from Cable TV is the most frequent problem and it is not caused by improper installation. Simply having Cable TV causes Parasound amps to malfunction.

The only true remedy is to fix the source of the problem.

Source of the problem is Parasound poor grounding design. They should have figured it out that millions of households in USA have cable TV or satellite TV.

The problem is in gear manufactured by a third party

All those products are certified for household use and they make millions of products every year while Parasound sells couple of thousands per year.

I think I'll just leave it as is for now, and if I ever feel the urge to in the future, call an electrician.

Sorry to disappoint you but electrician will not help you or even the cable guy. The only solution is to buy some transformer to filter cable TV and in case of satellite TV there is no solution. Remove the cable TV out the wall and see if noise is gone. I believe there is some internal interference between power lines and cable TV and has nothing to do with cables.

[mikepinkerton]

The only solution is to buy some transformer to filter cable TV and in case of satellite TV there is no solution.

Wrong. While the (simple) method that fixes cable won't fix satellite, it's still pretty easy to fix. I solved my sat problem with a 12ga wire between the sat box and that A51 which unified the grounds. Even cheaper than the cable solution.

Do a search on AVSForum and you'll find a lot of posts about ground loops with external amps and you'll see the posts have nothing to do with Parasound.

-Mike

[bhuskins]

Buzz coming from Cable TV is the most frequent problem and it is not caused by improper installation. Simply having Cable TV causes Parasound amps to malfunction. Source of the problem is Parasound poor grounding design. They should have figured it out that millions of households in USA have cable TV or satellite TV. All those products are certified for household use and they make millions of products every year while Parasound sells couple of thousands per year.

YOU DON'T KNOW WHAT YOU'RE TALKING ABOUT!

IT'S NOT EVEN WORTH DEBATING WHEN YOU SPEAK THIS KIND OF BS.

I've sit back and listened to your post...and enough is enough. Quite spreading such inaccuracies. This is some of the worst posting I've ever seen on any forum. Ever heard of the UL? Get the book and read it, then come back and spout your comments.

Brent Huskins
Media Design

[Peter Nielsen]

IT'S NOT EVEN WORTH DEBATING WHEN YOU SPEAK THIS KIND OF BS.

:agree: Marshal is a troll... :f>

We already got an inkling about that Marshal is a troll from reading one of his very early posts where he claims the FCC has something to do with regulation of how much power an appliance is allowed to consume. We all know that if anyone were to dictate something like this, it is of course the Underwriters Laboratories (UL), and/or the Conformité Européene (CE) for the rules that apply to European countries.

Peter

[Chris D]

I'm out of town right now and can't take time to read these threads tonight and see what exactly is going on.

So for tonight I'll just ask that whatever shenanigans are going on stops... I'll take care of more when I get home.

[Marshal]

I solved my sat problem with a 12ga wire between the sat box and that A51 which unified the grounds

Point is that only Parasound amps, and some other supposedly high-end amps cause these problems so it is obviously their fault. Why should you or anyone else have to use a wire to make some bogus loops in order to prevent buzzing or humming from faulty wired Parasound amps?

I've sit back and listened to your post

I wonder how did you do that, I mean listen what I wrote? You are a strange person.

And for the end just think about following:

1. Is your Parasound amp the biggest consumer of power in your household?

2. Why 1850W hair dryers, vacuum cleaners and deep fryers all have two prong cords and they don't emit any buzz?

3. Why all buzzing problems come only when Parasound amps are introduced into systems?

These things happen when hippies from '60 become legends in audio design. Instead of attending college to learn more about electricity they smoked their lives in marijuana. This is why reading books and studying is far more important than smoking grass.

And your bestial and mad dog reactions on my posts only further prove my point. It seems that some of you have finally realized how you or your parents wasted your lives in '60s.

Who else is using three prong IEC cords? Computer industry, of course! Who created it and who dominates it? Hippies fgrom '60s, of course. Why do we have security holes, non working computers, bugs, crashes, cracks and all the nightmare that comes when word computer is mentioned? Because of people who smoked their lives and left colleges like Bill Gates and the rest of the company. Did I mention that DVR I recently got, designed by company owned by Paul Allen experienced hum and was picking noise from inside of the unit.

People who went to college and have their degrees know how to properly ground electronic equipment with two prong cords. So much about brave new hippy marijuana world. Flush the '60s toilet please!

[bhuskins]

What an idiot...I thought you were banned from this forum.

If not, it won't be long.

Your insight into the causes and correction to ground loop (and other topics) are most ignorant.

I would point you in a direction to learn about the topic, but you won't even bother.

Brent Huskins
Media Design

[NMyTree]

So hippies from the 60s and marijuana are the cause of all the worlds three-pronged electrical grounding problems? :huh::huh:

And a majority of these hippies are designing Parasound amps? :drinker::drinker::drinker:

Oh my god!


:rofl: :roflmao::roflmao::roflmao:


Holy hat! This has got to be the most ridiculous and absurd rant, I have ever seen!:smackbutt::smackbutt:

[Chris CRt]

2. Why 1850W hair dryers, vacuum cleaners and deep fryers all have two prong cords and they don't emit any buzz?

Well, let's see. I think hair dryers have a distinct buzzing sound to them.

So do vaccumm cleaners.

Deep fryers make a bubbly noise though. So, I'll give you that one.


Uh, guys, WTF??!??! What a tool.

I have a ground loop hum, but right now I'm too lazy to do anything about it. I know what's causing it (Satellite box) and I think I'll give the 12ga wire bit a try. If that doesn't work, I'll go smoke some grass and think about my hippie parents.

:T

[bhuskins]

I wonder how did you do that, I mean listen what I wrote? You are a strange person.

I'm sorry that metaphor is beyond your comprehension.

Brent Huskins
Media Design

[Peter Nielsen]

Instead of attending college to learn more about electricity they smoked their lives in marijuana. This is why reading books and studying is far more important than smoking grass.

Well, get on with the reading then and stop smoking! :rofl:

Peter

[NMyTree]

BTW, Bill Gates was born on Oct. 28, 1955.

He was all of 15 years old in 1970.

Not exactly a "Hippie" from the 60s who wasted his time smoking pot.

One more thing, while I certainly don't smoke pot and am for the most part anti-recreational drugs, I have known some extremely brilliant and highly productive people, who are employed in important positions, who do smoke pot.

Pot is no worse than alcohol. If you abuse it, it could ruin your life. If you use it sparingly, it won't effect your life and productivity.

[nicholtl]

"Pot is no worse than alcohol. If you abuse it, it could ruin your life. If you use it sparingly, it won't effect your life and productivity."

Amen!!

[Chris D]

[moderator mode on]

Okay, keeping this somewhat lighthearted, this is rather funny that we've taken a MASSIVE turn from talking about ground loops to debating the effects of marijuana.

Moderator Point 1: We're back on topic now.

Moderator Point 2: I loathe censorship, so none of the above posts are being deleted. However, all parties involved need to make sure they're posting factual information and scientific engineering if they're going to talk about design details so as not to mislead uninformed club members. Some posters have been notified via private message to correct this problem.

Resume discussion... but play nicely, please, so I don't have to lock threads.

[/moderator hat off]

[jshood]

Testing and eliminating grounding problems

Wow! Who would have thought that earth ground would cause such a ruckus! Since I'm new and this is my first post, I'll post here where everone seems burned out - or should I say flamed out - on the topic.

I have a classic parasound setup and I too had ground loop problems -- but ground problems in house wiring have nothing to do with any particular brand of appliance. So I will state the problem and then how I solved it. Cheater cords, lift switches and other "symptom fixers" are not the way to go.

The Problem:
I have a PC with a m-audio 24/96 soundcard connected to my parasound pre-amp with RCA cables. The PC is on one outlet, the preamp on another. HUMMMM! If I disconnect the PC, no hum from the preamp. There is a difference in potential between the two electrical outlets. What brand electronics you have hooked up doesn't matter.

The Solution:
First use an inexpensive line tester (a 3-prong plug with LEDS to show if the outlet is wired correctly. You will be surprised how many of your outlets are wired wrong! If wired correctly and you still have hum, the easiest way to put your outlets to ground is to connect a wire from the outlet ground connection and run it outside and connect it to an 8-foot copper rod. You can buy the rod at any hardware store. Also buy a brass connector so you can fasten the wire to the rod. Works every time.

[Chris D]

Heya, jshood, and welcome to Club Parasound and the Guide! :banana:

Thanks for the tips, that's good stuff. Matter of fact, I think I need to buy me one of them line testers.

[mitch57]

Yeah! Where do you buy these at and what are they called?

[blownrx7]

Circuit Analyzer aka Polarity checker aka Outlet tester

They are only about $5 and are available at most hardware stores. It will check for polarity, reversed wiring and lack of grounds - very useful!!! :T

[mitch57]

They are only about $5 and are available at most hardware stores. It will check for polarity, reversed wiring and lack of grounds - very useful!!! :T

Thanks. I'm going to get one.