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Discussion Starter #1
I purchased a xpa 5(gen 1) earlier this year in March. Immediately after attaching the rca's the dreaded "hum" was there. Ground loop? Always is.... but who's fault is it? Your equipment? Interconnects? Cable box? Lack of a power conditioner? ........... All of them are a maybe?

Ok, so what happens when you've tested everything else, and all is ok... but the hum is Still there????

WARNING---THIS IS NOT FOR EVERYONE---- ONLY FOR A VERY FEW OF YOU WHO HAVE TESTED AND TRIED EVERYTHING ELSE.........TO NO AVAIL.

Check for continuity between rca's and chassis ground on all of your other components. If all of your other components rca's are grounded to the chassis and you've quadruple checked every other possible ground loop issue.... you very well may have just solved your problem!? Contact the guys at Emotiva and let them know what you've found out. If you have a gen 1 and are under warranty ask them very nicely to modify the amp to "mesh" with your system. Might cost you the shipping there... but the impossible hum just might disappear. Again, this is very rare! But the issue does exist. If you've tried everything else.... do this test and see what you find?


If you think this is a possibility for you.... another way to test this theory is to disconnect everything from preamp including power.... connect only one rca's to xpa5... check for hum..should be none. Now connect a second rca....is the hum there????

Again, this isn't for everyone... Emotiva helped me solve this issue. Their customer service is top notch!... I don't want to have every person with a humming xpa5 to think this is the issue.... it's very rare. Just hoping if there are a few of you who do have this issue.... you'll find your way here and enjoy the amp that it's best!
 

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Discussion Starter #2
My xpa-5 has had this grounding modification done by emotiva. I'm due to receive the amp back by the end of the week. I spoke with Lonnie about the modification and he feels confident this will eliminate the problem!!! I can NOT wait to get it back and plug it in!!!! Also, Lonnie told me the amp was ran on the burn in machine two days solid to be sure the modification is as "bullet proof" as possible. Finally being ran through a complete round of tests that will be included with the amp when it's returned. I will post pics of its performance tests as soon as I have them. Again, NOT at all trying to pretend the is and
"end all" solution... but I'm hoping there are a few of you out there out of all the xpa-5 owners who may benefit from this!!!!
 

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and yet another reason to buy emotiva.

dave
 

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Discussion Starter #5
Yes chashint, shipping both ways was covered. I will have it tomorrow afternoon, and will post here as soon as I know for sure it has eliminated the issue. I'm super excited!!!!.. really hoping for good results!!!!
 

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Im due to install an XPA 3 tomorrow...

Can any of you EMOTIVA owners verify that the hum was still there after using BALANCED inputs ?? Most likely your using a RCA that was made of inferior wire and picked up some type of noise....No one has mentioned trying XLR cables , this is why Im asking....
 

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Discussion Starter #7
Rts.. I appreciate your suggestion. However, I tried three different sets of Interconnects (all rca though).. monoprice, monster, and finally blue jeans cables. Along with three different receivers as pre amps. My biggest concern is that the ground is lifted on the xpa5... meaning the other end of the 3 prong plug you see is a blank. Everything is always going to want to find ground. So in theory, the second xlr's attachment would "create" the ground loop, just the same as the second rca does in my case. The way to fix the problem, is to ground the rca's input boards to the xpa5 chassis ground. Giving a dedicated path (hopefully with the least resistance to ground) which will allow the rca to focus on carrying signal, instead of them trying to ground the input boards to the chassis ground on the receiver/pre amp. Which is the "hum" that im afraid the more and more i sit here and think it... may be much more common than I'd first thought.?!?!?

We will know for sure tomorrow.... good k ice with your xpa 3 install!!!!
 

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Yes chashint, shipping both ways was covered. I will have it tomorrow afternoon, and will post here as soon as I know for sure it has eliminated the issue. I'm super excited!!!!.. really hoping for good results!!!!
Excellent, I hope it works for you too.
 

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Discussion Starter #9
I just got the xpa5 back from emotiva... The repair ticket states... "ran new grounds for each amp module and input board. Sure enough the blank on the xpa5 power plug now has a 3rd prong. As soon as I plug it in and test I will post results and pics!!!!!!! Audio precision signal to noise ratio is as follows. Ch 1 110.709db, ch2 112.522db, ch3 109.376db, ch4 110.840, and ch5 108.389. Not sure how good or bad that is?!?!? Maybe someone else can explain this rating in further detail?!?!?! Time to plug it in already!!!!...... dum dum dummy mm
 

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Discussion Starter #10
It's official... All my time spent on troubleshooting wasn't in vain.!!!!! While I can't honestly say it's dead silent... I have to stick my ear against the grill of the center channel and try to listen to a sound I know existed. Anyone who just installed the amp and didn't know of the issue... wouldn't have a clue in a million years it isn't silent...unless of course, they decided to press their face on the speaker grill!!!!...lol!!!

I'm trying to upload pics. .. but it won't let me. File size is too big...1.8mb and the limit is 293kb...????
 

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Interconnects with the shield connected at only one end may have avoided that hum issue. I haven't used Audioquest ICs in years, but I know the older series (Topaz thru Diamond) all had the shields connected at only one end. I never once had a hum problem using any of them.

No amp is going to be 100% silent due to the existence of residual thermal noise (a.k.a. Johnson-Nyquist Noise) in electrical circuits. If you have to press you ear up against the speaker to hear any noise, I would say that is excellent.
 

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Last night @ client #1, I got the EMOTIVA XPA 3 and the new MARANTZ 5008 setup along with a new MONSTER HDP 2500 AC Filter...

The Audyssey MultEQ XT and Marantz setup ran with no problems - I even hooked up one of the surround speakers out of phase initially just to keep the Audyssey MultEQ XT honest... it did detect the surr speaker as out of phase correctly...
Next I just had to listen to the fronts for the hum issue others have reported... At FULL gain on the marantz there is absolutely no hum and I had to put my ear right up to the speakers to hear a barely audible hiss .... and I do mean barley audible....I could not hear it at all 2 ft away from the speaker.... its DEAD quiet ... The interconnects were some that I made out of a quality quad sheild RG6 and ProConnect RCA compression connectors...
As it was quite late by the time I finished programming the remote for the new equipment I did not get a chance to really hear the system at anything other than very modest volume :sad:... so Ill have to report back on the full out test drive later....
 

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It's official... All my time spent on troubleshooting wasn't in vain.!!!!! While I can't honestly say it's dead silent... I have to stick my ear against the grill of the center channel and try to listen to a sound I know existed. Anyone who just installed the amp and didn't know of the issue... wouldn't have a clue in a million years it isn't silent...unless of course, they decided to press their face on the speaker grill!!!!...lol!!!

I'm trying to upload pics. .. but it won't let me. File size is too big...1.8mb and the limit is 293kb...????
Even though it's unfortunate that you had to hassle with it, the fact it got fixed is great news.
Time to finally enjoy your toy.
 

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Discussion Starter #14
I have an interesting update I'd like to add. Last night, I sat down to watch a movie... The first time I'd done this since receiving the amp back... guess what!?!?!? The scariest sound I've ever heard come through my speakers!!!!!! Come to find out the tv has a true 3 prong plug.... The modded emotiva does as well! !! This was the sound of an actual ground loop!!!!!!..... NOT at all what I "thought" was my issue all this time!!!! It was easily fixed by using a 2 prong adapter which I'll switch for an ungrounded d plug from an old sub I have.

I am now nearly certain the hum coming through most of these xpa5 amps isn't a "ground loop" at all. I believe it's really a poorly run ground scheme that allows the "pick up" of the amps on powersupply/transformer. Iffff you turn everything off and stick your face literally on the xpa5 you can here the same "hum" I was trying so hard to describe.!!!! Again, if you speak t nearly $1000 on an xpa5 and have a hum you just can't fix through normal "ground loop" procedures.....don't be shy, call them up and see what they have to say about it!!!

Really really hope this will save someone else from a whole lot of time spent in the ground loop troubleshooting "wormhole"!!!!
 

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Discussion Starter #15
Those of you who are using Android and are having trouble uploading pics.. I've figured out a way. Take a pic. Send it via email to yourself. This will give you the option to reduce the files size. Choose 10 percent. Go to your email inbox... download the modified files back into your galley. You will find them in your gallery under downloads. No log in to home theater shack. Choose advanced reply... upload manage files.... and waaaalaaaah!!! You're all set!!!

Here are my 3 latest attempts.
 

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I have an interesting update I'd like to add. Last night, I sat down to watch a movie... The first time I'd done this since receiving the amp back... guess what!?!?!? The scariest sound I've ever heard come through my speakers!!!!!! Come to find out the tv has a true 3 prong plug.... The modded emotiva does as well! !! This was the sound of an actual ground loop!!!!!!..... NOT at all what I "thought" was my issue all this time!!!! It was easily fixed by using a 2 prong adapter which I'll switch for an ungrounded d plug from an old sub I have.

I am now nearly certain the hum coming through most of these xpa5 amps isn't a "ground loop" at all. I believe it's really a poorly run ground scheme that allows the "pick up" of the amps on powersupply/transformer. Iffff you turn everything off and stick your face literally on the xpa5 you can here the same "hum" I was trying so hard to describe.!!!! Again, if you speak t nearly $1000 on an xpa5 and have a hum you just can't fix through normal "ground loop" procedures.....don't be shy, call them up and see what they have to say about it!!!

Really really hope this will save someone else from a whole lot of time spent in the ground loop troubleshooting "wormhole"!!!!
So in fact your TV being ON caused a ground loop... You lift the ground on the TV and the hum goes away ....
Correct me if Im wrong but this is not a design fault of the amp....
 

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Discussion Starter #18
Rts100x5,

I appreciate your response. However, I think you should read through the thread... not just the last post... before you draw incorrect conclusions!!!

I have been a mechanic for 15 years... If you believe I spent months of time troubleshooting and wasn't able to do cover the tv as a source of ground loop... I'm very sorry... but your sadly mistaken.

I was letting the others know that after recieving a properly working unit... and testing it all to only music sources... All was well. Remember, the xpa 5, if you've read the thread... has now had a true ground added to the power cord... an unmodified xpa5 does NOT have a third prong when it's chassis attaches to the power cord. Again, after adding this third prong.... it did actually cause a ground loop with the tv. This took me all of 2 mons worth of troubleshooting to figure out. Hope that makes more sense. If for some reason it doesnt?!?!? Please take the time to read through the thread so that it does before you make another attempt other at insulting my intelligence.

Thanks bro!!!! Take care!!!
 
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