I did call and speak to Scott earlier today, and I will be calling him tomorrow with an update, but I am looking for any other suggestions out there;

I have the 7700 amp that I had connected with an Onkyo PR-SC886 via XLT connectors. Today I swapped out the 886 with a Marantz AV7005. Everything was turned off and unplugged. I made all the connections, did the set up and everything was fine.

I ran Audesssey and at some point between it finishing/calculating-the command on screen to unplug the mic-and unplugging the mic, the dreaded ground loop noise appears in all speakers except the subwoofer.

I know the noise cuz back when I first got the amp I had the same issue and Outlaw exchanged the amp for me and I went with the XLR cables.

Scott told me to see if the noise was coming from all speakers and the sub (I cant hear it in the sub after turning the Outlaw EX sub on its face)but it is coming from the rest of the 7 speakers.

He also told me to plug the Audessey Mic back in, then remove it. I tried that and it had no effect on the noise.

I think my 5 year warranty is up, and I DREAD paying shipping for a 100 pound amp both ways for the repair......

I will be calling Scott again in the morning. Anyone else have any thoughts?

Check all your connections to make sure they do not have a stray wire to ground. Both the amp and the AVP should share the same common ground (as should the rest of the equipment). If the ground plane is different between the various pieces of equipment it allows current to flow across the ground and usually is the cause of the hum. I don't see a surge protector/voltage regulator in your profile. I don't subscribe to the need for voltage regulation but for lightning protection and to provide a common ground they are great. Inspect the ground connectors on the AVP and the amp assuming the AVP has a grounded plug. If it doesn't have a grounded plug, you may need one. Sometimes the ground in the receptacle isn't secure to both outlets. Try plugging an extension cord into one receptacle and powering both pieces of equipment from the extension cord. If the hum goes away the house circuit is suspect. Don't run this way but it is a good way to check the receptacle.

Disconnect all the inputs to the amp and turn it on. If the amp is the problem you should hear the hum. If no hum, then plug in one input at a time until you do hear the hum then check that cable by swapping it with another. If both have the hum then check the connector on the AVP and the Amp.

Profile updated, I do have a Monster Power 2600 for most of my gear. The TV, PS3, Toshiba HD DVD player, Wii and the Sub are all connected to a Monster Power bar 1100 I believe on a different outlet, same 20 amp circuit as the rest of the stuff.

Thanks for the troubleshooting suggestions. I will be trying to find the culprit soon. I believe the Marantz AVP does not have a grounding plug, its a 2 pronger only.

The weird part is everything was fine, it was sounding great and then while it was on the hum started.

Any piece of your equipment could cause the hum if it sees a different ground value. You could try plugging your 1100 into the 2600 to give all of the equipment the same ground source.

Cant, they are in different areas of the room.

Talked to Scott again today for 30 minutes. HUGE HELP! The good news is it is NOT the amp. I unplugged the centre channel XLR cable and turned on the Marantz and the 7700 only, and no noise from the centre speaker.

So, I unplugged everything except the XLR cables and speaker wires. No noise. Thats good, I think. I then plugged in the outgoing HDMI cable from the Marantz to the TV. I get the hum. I then tried it in the HDMI out #2, still get the hum. So, it looks like either the cable, or someting connected to the TV.

Thats all I got done today. I hope its just the cable, even though that will require snaking a new cable thru walls. Easier than a repair on the amp I guess. More troubleshooting tomorrow.....

I think your problem might be that you have two different isolated power supplies hooked up to different parts of your system. My guess is that as soon as you plug anything powered by the Powerbar to the Marantz it's going to start buzzing.

The 2600 has a grounding post according to the literature. If the 1100 has a grounding post (couldn't find anything that says it does)then you could run a wire between the 2600 and 1100 and see if that fixes the problem.

Otherwise you might be able to run a wire from the chassis ground of your TV to the post of the 2600. I'll have to say I'm not quite certain what will happen to your surge protection if you tie the isolated grounds together. In theory you'll be fine but it's probably a good question for Monster.

I had not thought of that EEman, however it was not an issue for the last several years with the 886. Any idea why it would do this 15 minutes after running the 7005?

I did spend another 56:00 on the phone with Scott today. What a great guy.

We think we finally figured it out; I unplugged all source components from the Powerbar 1200 and that didnt change anything. But when I unplugged all source components from the 2600 and unplugged the 2600 from the wall outlet, and plugged the amp and marantz directly into the wall, the noise/hum was "almost" non-existant. It was very, very, very, very faint.

So, either the two Monster Power units are conflicting each other, or the 2600 is no longer good. And of course, its past the 5 year warranty, so I guess I need to be another unit.

Any other thoghts on two Monster Power units causing issues with the other? I will run it by Scott tomorrow, or call Monster and ask them.

I think the 2600 just picked that moment to die. Most manufacturers have a pretty good idea how long their equipment lasts and adjust their warranty period accordingly.

Did you hookup of the 2600 and 1100 cause the 2600 to die prematurely? I doubt it. If the chassis were properly grounded then I'd think there's no problem running in this configuration. If not then I would have expected you to hear ground loop buzz well before now.

I also looked a little more into power conditioner operation ('cause I'm a nerd) and tying the chassis grounds together should not impact the surge protection.

Wouldn't hurt to get Monster's thoughts on the problem. They are the experts on their product.

I called Monster, and the guy did not really sound like a really knowledgeable tech, but who am I to judge. I explained it to him and he said it soundled like it took a hit, Although there were no storms in the area, or anything out of the ordinary. He said if I shipped the unit back, they would give me a discount on another.

I ended up ordering a Tripp Lite from New Egg, very reasonably priced and has a longer warranty than Monster. I wasnt looking for one of the really cool looking products like the top of the line Monster stuff (but it would look neat!), just something to protect my stuff.

He agreed that having the 2600 and 1200 hooked up at different outlets but same circuit, should not be an issue.

I agree that having both hooked up to the same circuit but different outlets SHOULD not be an issue but a loose screw on the ground terminal anywhere in that circuit could cause the problem. Tripp-lite makes good equipment and should easily handle your equipment. I would take another look at the circuit your TV is plugged into and make sure all the connections are tight since the hum is slightly present. Is the Tripplite big enough to handle all of your equipment?

I just got back from a trip out of town;

The new Tripp-Lite supressor (just arrived Friday) is a 15 amp model, same as what the old Monster 2600 was. The circuit itself is a 20 amp line, and it feeds everything (Plasma, Sub, Amp, and all the rest of the gear).

I would love to have bought a 20 amp Furman Conditioner/supressor, but it's just too much money.

In the past when I looked at how much power was being used with all of my gear on (using the amperage lights on both Monster Power units), and the volume set very high, they never went above 2 amps on either machine. To me, this means I was below 5 amps total draw when the The Plasma, Sub, and Amp where all on together at the same time (the rest of the gear uses a very small amount of power).

While I have inquired an electrician snaking 2 additional independant lines to my gear, I have not done so yet. It would be great to have another 20 amp line feed my sub (leaving the option for another Outlaw EX sub), one for the TV and other for my Amp by itself, The absolute NEED for it has not presented itself.

The Tripp Lite just arrived Friday, and I have not had time to hook it up yet, but I will either later today or tomorrow.

I hooked up the Marantz 7005 and Outlaw 7700 amp directly to the outlet. I turned on just the amp and there is NO noise coming from the speaker. I turned on the 7005 (no cables other than the XLR cables are connected to the 7005) and i get a VERY slight buzz coming from the speaker. From 5 feet away, it cannot be heard.

Now getting ready to connect all cables and plug everything into the new Tripp Lite....

Did you try disconnecting the XLR cables one at a time to see if one is causing the problem?

I will be going thru those tomorrow;

Hooked everything up and its still making the buzz.

I hooked up the Marantz 7005 directly to the outlet and it still buzzes. I checked the outlets and they are grounded properly. Unplugging everything and plugging it all in is tiresome.

I wanna cry.....



If the only connections are the Marantz connected to the amp via XLR, and the speakers to the amp, and both are connected directly to a dedictaed outlet, the buzz is there but subdued.

Later today, I will unhook everything again, and listen for the noise. Then, start making connections one by one to see what, if anything, makes the buzz louder. Im wondering if the new Marantz 7005 is defect.

To make a long story short;

Keeping the XLR cables connected, The more HDMI cables I connect regardless of input or output, the buzz gets louder after 2 cables are connected, and louder after 3. With just 1 connected the buzz is barely noticeable. With nothing connected its VERY quiet (perfect).

Jim at Outlaw gave me directions to do a soft (keeping all info) reset, and a hard reset. Soft didnt work, no to try the hard reset.

You keep the interfaces digital to eliminate noise and it causes a ground loop...Wow

Does this happen even when the sources are plugged into the same power source?

Can you connect a ground wire between the sources to see if the problem goes away?

What brand of HDMI cables are you using?

Sounds to me like you're pretty close to beating this one.

"Does this happen even when the sources are plugged into the same power source?"

Most of the source componenents are plugged into a brand new Tripp Lite supressor. The amp, preamp, DVR, 400 DVD jukebox, 400 CD Jukebox, Oppo, turntable, are plugged into the Tripp Lite. I tried connecting the preamp directly into the wall outlet (bypassing the supressor) and that did not help. The Plasma, sub, PS3, wii and HD DVD player are connected to the Monster Powerbar 1200 at a different outlet, but same 20 amp circuit.

"Can you connect a ground wire between the sources to see if the problem goes away?"

Not sure how I could do this.

"What brand of HDMI cables are you using?"

Most are Monoprice. I have a 35 footer going from the PS3 to the preamp, and another 35 footer going from the preamp to the TV. This has never been an issue. I have a supplied HDMI cable going from the Oppo to the preamp. Again, this has not been an issue in the past with the old 886.

Remember, all was fine when I originally hooked up the Marantz after I replaced the old Onkyo 886. After running for about 20 minutes and doing a run with Audessey on the Marantz, thats when this whole fiasco started. I also opened the electrical panel and made sure all negative, positive and grounds were tight, and they are.

BTW, the hard reset did not work either.

Disconnect the hdmi to the tv since it is common to all of the hdmis. Could be a problem with Marantz. Try the audio with the tv disconnected and unplugged from any points.

Xenon Man, I have disconnected the HDMI to the plasma. If one HDMI cable is connected from 1 source, the buzz is very faint. If the only HDMI cable is connected to the plasma, its very faint. If I add a second (in or out) the buzz increases. If I add a 3rd (in or out) regardless if its input 1-5, the buzz gets louder (annoyingly so).

Is your TV plugged into the same ground source as the Marantz? Also disconnect the cable or satellite too.

The TV is plugged into the same circuit, but I also tried plugging it into a different outlet/circuit with the same result.

I have also disconnected/unplugged the DirecTv DVR and cables/power, with no change....

New high speed up to date HDMI cables were ordered monday from monoprice. Well see if that helps the buzz....

So.
1. It worked for at least 20 minutes.
2. You ran Audessey and it broke.
3. A hard reset (which will take Audessey back to it's default config) didn't fix the problem.
4. As you add more loads (connects) to the HMDI circuit the noise gets worse.

Things are starting to point to a hardware failure in the Marantz. Maybe the power supply for the HDMI circuit is on the fritz and the more connects you hookup the worse it regulates.

Hope the new cables work. If not I think it's time to send the Marantz back.

You are correct EEman,

I also multiple analogue hookups (CD, multi channel from the Oppo, turntable and a VCR) and with these hooked up and no HDMI, there is no noise.

Start hooking up HDMI cables and it appears.

I should have the new HDMI cables tomorrow. I am going to move a smaller LCD HDTV into this room and hook it up with the current set up but if the new cables dont work, I will ask Outlaw for a replacement unit.

cp1966,

Be sure to let me know if the new cables don't resolve the issue. I greatly appreciate the efforts you have made to isolate the actual cause of the hum.

Best,
Scott

Scott, you and Jim have been VERY helpful. I REALLY DO appreciate all the time you guys have spent helping me over the phone.

I will keep you posted.

New HDMI cords finally arrived very late in the day today. I will hook them up tomorrow.

Long cords makes no improvement.

Calling Scott......


Rats, Scott is out, Jim on the phone with another customer.

I also tried running a ground from the 7005 to a water pipe, a ground from the DirecTv DVR to a water pipe, and the DVR to the 7005; No difference.

I may have solved it;

Hooking up all the sources via HDMI (DirecTv DVR, DVD jukebox, Oppo, PS3) in any combination of inputs seems fine ( a very very very small amount of noise audible in speakers), and even having a HDMI cable hooked up at the output of the 7005, it sounds clear.

But as soon as I connect the output HDMI to the TV, BINGO!

I am running a second test to confirm as I have tried so many different configs......


*** UPDATE***

Unplugged the plasma for about 90 minutes. Ran the above scenario and its the same;

4 source componenets connected to the Marantz 7005 via HDMI an 0 HDMI outputs connected = no noise. Connect a HDMI to output 1 and no noise. Connect the other end of the HDMI to the Plasma = noise.

I connected the output to a 32" LCD HDTV and there is a very small amount of noise, but nothing like when its connected to the plasma.

Jim is sending out a replacement 7005. I will also contact some plasma repair places and see if they have seen this before.

What else is connected to the plasma directly? Could it be the ground from the TV is compromised by equipment connected to it?

Only a set of component (red, green, blue video and L & R audio cables from a Wii) whicg I believe Jim had said would not affect any noise.

I will be sure to unplug those as well in the morning and try it again.

I also currently have the TV power cord (3 prong) connected to the outlet directly, bypassing the monster Power 1200.

Unplug everything from your TV. Even if it is only video it still has a ground somewhere. Disconnect the Wii and the power cord from the TV and see if the noise is gone. If it is then plug in the TV to the wall and check again, then do the same with the wii.

Will do, but I think I did this in my earlier troubleshooting escapades....

More info;

Outlaw 7700 amp, 3 prong plug
Marantz 7005 preamp, 2 prong plug
Panasonic Plasma HDTV, 3 prong plug

I wired a 14 guage wire from the preamp (ground scew) to the amp (screw on top front) to insure a ground. I tried running that wire right to a water pipe, and even though the DirecTv line is grounded right after it enters the house and prior to it feeding a 4x8 mulitiswitch, I grounded it again onto a water pipe above the stereo cabinet.

None of this helped.

I just double checked the connections at the plasma;

Nothing plugged into the plasma and plugged into the wall = no buzz
Only the 1 HDMI cable plugged into the plasma w/o it plugged into the wall = no buzz
Plug the plasma into the wall w/o turning the plasma on = buzz

This was done with everything else plugged into the Marantz 7005 (4 HDMI in, 1 out, plus 2 optical cables, and 8 RCA cables from my Oppo into the 7.1 input).

Suggestions?

..Sounds like it is coming from Plasma....can you switch in another TV/Monitor, then try?? or Maybe, isolate outlet for Plasma plug???Or even try running an extension cord from other section of house to Plasma plug....

cp1966, this is truly some great detectve work on your part. Ground loops are the worst.

For a test you can try one of THESE. For the test do not connect the ground lug.

If the noise goes away then the safety ground is the cause of the problem. It's strange that you are having this problem even though you are using a power conditioner. Maybe the Saftey Ground (third wire) in you outlet box is floating/not connected or else something is funky in wiring of the TV?

If this doesn't solve the problem then I'd question if the outlet is wired correctly or somehow sustained damage.

It is likely that even when the TV is off it is still trying to keep some components warm to aid in quicker startup. Maybe the TV is causing the interference directly. Try to run the TV as suggested above with the ground pin bypassed.

I have tested the outlets and they are ok, and grounded correctly. I haved checked all the wire connections in my electrical panel, all tight. All speaker and XLR cables are nice n tight

I have hooked up the hdmi cable to another TV (32" LCD) in another room, and there is still a little noise but not as much as with the 65" plasma.

Should I try the cheater plug on both the plasma and the outlaw 7700 Amp?

I would try it on the TV just as an experiment. If you try it on the 5500 don't use it at too high of power. Also the ground pins on the XLR connectors may not function fully for noise reduction but should be OK.

I would try it on the TV just as an experiment. If you try it on the 7700 don't use it at too high of power. Also the ground pins on the XLR connectors may not function fully for noise reduction but should be OK.

Okay, went out and got three of the "3 prong to 2 prong" adapters. I disconnected everything except the XLR cables from the preamp to the amp and all speakers;

* Just the amp on, dead quiet!

* Took the 3 prong Plasma electrical cord and used a 2 prong adapter and plugged it in and I got buzz

* Used a 3 prong adapter on the Outlaw 7700 amp with the TV using the 3 prong cord and I got buzz

* Used a 3 prong adapter on the amp AND on the plasma and the buzz is 90% GONE!


I tried connecting the TV to both the dedicated outlet and also to the Monster Power bar and that did not make a difference.

For experimental value, I connected a ethernet cable and downloaded and installed the updated frimware. While the process was running, there was no buzz, but when it restarted, the buzz was there.

Thoughts?

Have you tried connecting a ground wire between the Marantz the 7700 and the TV? It sounds like a ground loop between the amp and the TV. Connecting a ground between the chassis of all 3 eliminates that loop.

Remove the 3 prong to 2 prong adapters and do that? I probably could as a temporary fix to see if it kills the buzz. Doing so as a long term solution would be very difficult as they are not near each other. The amp, pre, DVR, Oppo, and the CD and DVD jukeboxes are in a wooden stereo cabinet about 15 feet away and on a perpindicular wall to the TV, PS3, Wii and HD DVD player.

Just temporary for testing. I would leave it as is with the adapters and fine a good chassis screw and connect a piece of speaker wire to all three.

So right now you only have power cords, HDMI and XLR (and speaker wires) in the system correct?

Have you tried unbalanced connects from the Marantz to the Amp? (Takes the XLR out of the equation)

Have you tried running component to the TV from the Marantz, taking the HDMI out of the equation?

If either of these works then the grounding scheme related to the cable removed is wrong/broken.

I have some other suggestions that may provide insight however they may cause damage to your speakers, so we'll leave that on the table for now. Basically I want to get the Marantz out of the loop and feed audio directly from the TV to the amp but the TV specs don't show analog outputs so I don't know how to do this gracefully. Any ideas?

Do you have a volt meter?

Not necessarily.
It is entirely possible that the "feed" to the TV has lost its ground. I have seen cases where landscapers busted the grounding wire to antenna / satellite / cable ...

I have used these for problems with cable -- http://www.jensen-transformers.com/iso_vid.html

You might also check to see if there is a grounding block and ground rod with nice un-corroded wire firmly attaching them -- http://www.amazon.com/Cables-Go-41037-Si...grounding+cable


If you have a grounding issue with DirectTV this might have enough bandwidth to work -- http://www.mcmelectronics.com/product/33...CFY1DMgodxi8AxQ


Good Luck!

The pre, amp and the TV?

Yes, I have a voltmeter.....

I get the new Marantz tomorrow; regarding plugging stuff in and making connections, do I need to have everything off and unplugged when making the connections (XLR, RCAs, HDMIs, etc...)?

It is always safest to have all equipment turned off especially the amp and subwoofers. Once it is all off you just have to disconnect the old and reconnect the new.

I received the new AV7005 last week. I hooked it up yesterday and slowly started to connect stuff. At first I tried using RCA cables to connect the 7005 to my Outlaw 7700 amp. That did not go well, awful noise. I took them out and connected my Outlaw XLR cables and with just those 2 components hooked up and my speakers connected, DEAD SILENCE!

Then I started connecting stuff, Here are the results of my testing scenarios;

#1; Preamp connected to Amp via XLR (7 channels), Amp feeding speakers, amp on = no buzz, turn on preamp = no buzz. All else unplugged and unconnected (no power or HDMI cables, no subwoofer)
#2; Connect a HDMI cable to HDMI out #1 at 7005, EXTREMELY low buzz, I will rate it at .5 or 1/2.
#3; Connect above HDMI to HDMI in #1 at unplugged Plasma HDT, buzz a little more noticeable, I will rate it at “1”.
#4; Plug in plasma, buzz is heard, same as when plasma is not plugged in. I will rate it the same, a “1”.
#5; Attach cheater plug to TV and plug in, stays about a “1” and a crackle is heard every 5-8 seconds. Remove cheater plug.
#5; Attach both DirecTv RG6 lines to DVR, buzz stays a “1”. Plug in DVR, buzz remains a “1”.
#6; Disconnect the HDMI out from the 7005 and buzz goes back to a “.5”.
#7; Connect a HDMI in at number 3 on the back on the 7005, buzz is a tad louder, a “1”. Connect the HDMI at the DVR and the buzz is a tad louder, now at “1.5”.
#8; Disconnect the HDMI cable at both ends for the DVR (at the DVR and the input at the 7005) and disconnect the HDMI out on the 7005 and buzz is back at “.5”.
At this point the TV is still off but plugged in.
#9; Connect a HDMI to an output on the 7005 and to HDMI 1 on the plasma and the buzz is back at 1.
#10; Connect the HDMI from the PS3 (plugged in but not on) with no HDMI connected to the 7005 out, buzz is at “.5”. Connect the HDMI out at the 7005 and connected at the plasma and the buzz is back to a “1”.
#11; Connect the HDMI from my Oppo BDP-93 (not plugged in) and buzz is at “1”. Plugged in, it remains a “1”.

Somewhere somehow there seems to be a ground loop occurring, and to me it seems like when I connect the HDMI to the TV to complete a connection between the 7005 and the TV, the ground loop is either started or exaggerated to the point where it is audible. The buzz rating of .5 is barely heard from 3 feet. Very tolerable if I was on my counch watching/listening to something. With the buzz rating of “1”, it can be heard at a distance of 12-13 feet, however it is very, very, low. When standing within 1 foot of the speaker it is quite noticeable.

I also tried conecting the Plasma to the same Tripp Lite Isobar using a tick 3 prong extension cord, and also plugged it in to a different outlet on a different circuit. Neither helped.

I connected the other sources(PS3, DVD Jukebox, and the DirecTv DVR via HDMI and the buzz got up to about a “2”. This is easily heard, but not "loud" at 12 feet.

I think I am going to try an AV Receiver and try that and see if it works, with and without the amp.

So in step 2 above the buzz starts when an hdmi cable is plugged in only one end with the other end unplugged? Did you try a differnt hdmi cable in that condition? If the tv hdmi cable is somehow the problem it could affect all your othe tests. You should not have any noise using the RCA cables. At this point I think it is a problem with the tv or a cable but that doesnt jive with the RCA cable noise.

It should not buzz with just the RCA cables hooked up (just speakers, RCAs and two power cords right?).

Go back to this setup and try just one RCA cable at a time. If it stays quiet with only one RCA at a time then start adding them one at a time (i.e. without removing the existing connects) and see where the buzz starts. Maybe your amp has a blown channel or power supply problem?

Regarding the 2 posts above;

XenonMan, you are correct, one end is plugged in at the 7005 and the other end is not plugged in at all. I have tried another brand new Monoprice redmere HDMI cable and the result is the same.

The noise heard with the RCAs was quie loud. Not "oh my god turn it off its too loud" loud, but it was WAY to apparent not to ignore.

EEman; correct, the amp and 7005 were both plugged in, speakers hooked up and the 7005 was connected to the amp via RCAs.

I will unhook the XLRs tomorrow or tonight and try the RCAs one at a time and see if that helps.

Thanks for the contiuing responses guys.

What position was the XLR/RCA selector switch in when the RCA connectors were installed?

Unbalanced.

Something is askew if you are getting noise out of the RCA connection and the XLR has some hum. Maybe your TV has lost its ground somehow or other.

Any thoughts on how to test that? I could try buying a new AC cord. However, keep in mind that running a HDMI cable to another smaller LCD HDTV, on another outlet/circuit, I still get the buzz.

I will do this again with the new unit in case I forgot as part of the troubleshooting procedure.

Before you do that let's go back to the RCA connect. You said with just speakers, amp and pre-pro you get buzzing. I'm assuming the Monster power converter is also hooked up?

What I'm thinking is there might be a ground offset between the pre-pro and the amp. If the offset gets big enough then even balanced connects are not going to help. It also makes sense to me that adding more cables to the pre-pro could make the ground offset worse. Can you ground strap the pre-pro to the amp somehow? Using the cheater plug with the RCA setup would also be interesting as that should float the amp earth ground.

However if you really want to understand what is going on, let's put the volt meter to work. We'll (i.e. you'll) be checking continuity so unplug the Monster from the wall.

1. Unplug everything from the Monster. Put the voltmeter on Ohms and check for continuity between the third prong of the input plug and the third prong of the output plugs. If the pictures I found of the internals of this unit are correct you should read zero ohms.

2. Now check the other two output prongs back to the ground prong of the output (or third prong of the input power if they are tied together). I can't tell from the photo if the neutral wire is tied to the chassis ground of the Monster. This will tell us.

2a. It looks like the outputs of the monster may be isolated from each other. Measure between two output power ports and seee if there is any continuity.

3. Moving to the pre-pro. Unplug everything but the power cord. Check for continuity between each of the two input power pins and the ground on the RCA jacks that goes to the amp (just to be clear that's the shell of the RCA jack NOT the center conductor). Check all RCA jacks to each of the power input pins. All these measurements should result in an open circuit. (Note: This is 14 measurements for a 7-channel system)

4. Now the amp. Do the same measurments as you did for the pre-pro but add the third prong of the power input for a total of 21 measurments. I would expect the RCA shells to be tied (0 Ohms) to the third prong of the power connector (earth ground). I don't know how Outlaw handles the neutral input on their equipment. This test will test us. If you see zero ohms between the third prong and one of the other prongs then the nuetral is tied to earth ground in the chassis.

5. With your newfound understanding of your system you should be able to draw a diagram of where the power and grounds are going for these three units. If not, let me know what you measure. I already have a sketch of what I think is going on but I don't know the internal connects for the units, so no smoking guns yet.

Whew, that was a lot. If you're still reading this, congrats. You might just be an electrical engineer

Thanks EEman, I will try steps 1-5 tomorrow when theres more light in the basement. I did try grounding the Marantz 7005 and the Outlaw 7700 and that did nothing.

I still have a Monster Power Bar at the TV, its a 1200, but the Monster Power 2600 has been replaced by a Tripp Lite Isolation bar and this feeds the amp, pre and some source compenents like the Oppo and the DirecTv DVR.


I got a Hum X and connected the Plasma to it. With the HDMI cable connected at the 7005 to the TV, and multiple HDMI cables connected to the 7005 inputs, except the DVR, no noise!

Connect the DVR via HDMI and the noise returns.

Connect the DVR via component video cables and the buzz is still there.

Tomorrow I am going to swap DVR. The one in th eroom now has a 3 prong plug, but I have a H22-100 (I think) in another room that is only a 2 pronger.

Did more work today;

Already tried to gorund the amp to the preamp before with no luck. Tried a diff DVR (2 prong), no help.

Hooked up a Marantz SR7005 to the amp via RCA and got buzz. The buzz even whirled a bit, changing pitch, loudness, it was wierd.

Hooked up the speakers to the SR7005 along with everything else; BLISS!

Looks like I may be selling the 7700 amp. I hate to, I love it, and it brought great sound to my speakers. But I cant go on with this loop or whatever else is the issue. I will be calling to return the Marantz AV7005 tomorrow



At least I have good sound working in my theatre....

Just a quick question, Is the TV connected to cable TV?
I have had all shorts of problems with the cable ground being at a different potential then the house ground.

I'm debating buying an AV7005 for myself, but don't want to if there are ground loop issues.

I have DirecTv, with multiple DVRs.

The AV7005 has received rave reviews. I believe it is a very nice product. Just my 2 cents, the internal circuitry may not be as good as other brands (hence my problems). Some others report the same issue.

Depending on your set up, you may love it. Most places offer free shipping with a return policy. Right now at just over a grand, its a great buy.

Scott and Jim at Outlaw have been wonderful to work with, and I wold highly suggest you buy here if you are thinking of getting one.

Have you disconnected the Directv cable for your testing? As far as I can tell mine does not have a ground other than the chassis ground through the plug and that is much different than the house ground circuit.

I did disconnect it when it enters the house. Within a few feet of the 4 cables entering the basement, it is conected to a grounding bloc. From there, the 4 cables go to a 4x8 multiswitch, and there is a nice thick wire that goes to a grounding block connected to a cold water pipe about 6 feet away.

So if you take the outputs of the AV7005 and put it into the 7.1 inputs of the SR would you get buzzing?

Does the SR have Pre-outs that you could hook into the Outlaw amp? That would also give you another data point.

Disconnect the DTV cable right at the receiver in case the circuit is the problem.

I could try that. I can do it tomorrow.

I think I tried that already, it did not help.

Dear cp1966,

I have been actively following this thread because I am experiencing a nearly identical issue (HDMI induced buzz), except that it is occurring with my Model 7900. I waited until now to respond because I didn't want to interfere with the troubleshooting of your issue. Bottom line: after conducting a nearly identical troubleshooting procedure as you, I will be returning the amp. Briefly, I have a Denon AVR3808-ci receiver (RCA preouts only), 3 sources all of which are connected by HDMI (65" Panasonic Plasma, Denon Blu-ray, and a Motorola DVR). Just like your situation, the buzz is caused by HDMI cables. With everything hooked up, the buzz is so loud that it is audible 15 feet away. When I remove the HDMI out to the plasma TV, the buzz decreases 50%, and when I remove the HDMI in from the DVR, the buzz stops entirely. Like you, I have swapped out cables, used cheater plugs, removed my Panamax conditioner, etc., but nothing stops the buzz (other than removing the aforementioned HDMI cables). However, again like you, when I take the Outlaw out of the picture and hook everything to my AVR, pindrop silence! Similarly, and even more telling, when I use my Emotiva XPA-5 as the amp, it too is pindrop silent using the same connections.

Given our nearly identical issues, I conclude that the giant transformers in these amps are effectively antennas that attract unwanted frequencies. Our situations are not consistent with a ground issue.

I am very disappointed that I have to return the amp, because it is simply amazing. Even at very low listening levels, 50 db below reference, the bass is significantly tighter than my Emotiva and the midrange is also much more clear. I can't even imagine the sonic improvement at levels approaching reference.

Good luck with your issues, and if you would like to chat further offline, let me know.

Amaheshw,

Very sorry to hear your situation. It sucks, doesnt it? Its a shame we can put a man on the moon but cant nmake a pre amp and amp work together in peaceful harmony!

I am waiting for a call back from Jim (I called Monday and left a message) to get a RMA. In th emeantime, I am considering wiring a new circuit to feed the amp and another to feed the TV to see if ican get this to work. I wanted to try running the SR to the AV to the amp to see if that worked as suggested earlier, but didnt have the time today.

I swear I have tried so many diifferent configs in my system.....

Anyways, I really do appreciate everyone chipping in and helping out. I do wish to keep the AV7005 and my amp. But if I have to settle, the SR7005 is a very nice piece.

We can't put a man on the moon anymore. We can't get men into space without another country picking up hitchhikers. Sorry the problem could not be fixed. I have the 7125 and the 7500 and both are dead quiet. Since yours is quiet until you connect an HDMI cable I would steer away from the amp as the problem.

I don't know. I'm beginning to think the amp is the problem. Something has gone bad and the power supply isn't regulating or a cap blew and DC isn't decoupled properly or something.

I also don't buy that the transformer is acting as an antenna as ferrous core toroids make lousy antennas. However I'll grant that something might be broke here too.

My 7075 isn't dead quiet. I get a little of what sounds like transformer delamination noise which is strange becasue I thought the transformers where ferrite core not laminated steel. Haven't popped it open yet to explore. The noise level is low-I can't hear it from more than a couple feet away.

XenonMan and EEman -- I appreciate your thoughts that this is unlikely to be a mere transformer design issue, as I hastily speculated. I have decided to give this one last try and will exchange the 7900 instead of returning it. Also, I had an extremely helpful discussion today with ATI. cp1966 I'm sure you have already tried this, but the technician suggested gounding all components together to a common point and terminating w/a crimp connector or something similar. I have only done this with 3 of my four components, so it may work. Will report back in mid-January when I have received the new unit and completed my troubleshooting.

UPDATE;

Outlaw did accept the return of the 7005. I auditioned the new 8801 and it works great; NO BUZZ!