Marantz AV7005 - serious ground loop hum

[darien87]

You said it was an open box didn't you? That's why it was an open box IMO. Someone else returned it; it probably had a bad ground and the person who returned it either damaged it or didn't bother to tell them it had hum.

Possibly. The story I was told was that they had loaned it to a guy who needed warranty work on a McIntosh processor to use for a few weeks while he waited. Who knows if that was the truth. But even if it was maybe the guy had it bouncing around in the back of a truck or something when he returned it. The replacement unit I got is open box also, but looks in better shape.

 

[AcuDefTechGuy]

You said it was an open box didn't you? That's why it was an open box IMO. Someone else returned it; it probably had a bad ground and the person who returned it either damaged it or didn't bother to tell them it had hum.

That's what I'm thinking too.

 

[AcuDefTechGuy]

So my "instant gratification" desire kicked in last night and I ended up driving to pick up the other 7005 last night, (about an hour each way ). I got home about 8:45pm and still had to cook dinner. But I'm happy to report that I hooked up a couple of XLR cables for the hell of it and no hum. The other one hummed even with only 1 XLR cable connected. So it looks like I had a defective unit after all.

Congrats.

Nothing better than when everything works out according to plan.

 

[PENG]

One bummer about the 7005 though is that it won't let you set the sub crossover any lower than 80hz. I would think that's kind of high

Are you talking about the LPF setting? If so, that one should be set higher than 80 hz anyway, I think Audyssey recommends 120 Hz. I believe the LFE signal could even be as high as 150 Hz, you definitely don't want to go below 80 Hz if you don't want to lose anything in the LFE channel.

 

[PENG]

Possibly. The story I was told was that they had loaned it to a guy who needed warranty work on a McIntosh processor to use for a few weeks while he waited. Who knows if that was the truth. But even if it was maybe the guy had it bouncing around in the back of a truck or something when he returned it. The replacement unit I got is open box also, but looks in better shape.

I hope all will be well and you could finally sit back and enjoy this high quality AVP, after all the driving and experimenting you really deserve a break.

 

[darien87]

Are you talking about the LPF setting? If so, that one should be set higher than 80 hz anyway, I think Audyssey recommends 120 Hz. I believe the LFE signal could even be as high as 150 Hz, you definitely don't want to go below 80 Hz if you don't want to lose anything in the LFE channel.

I believe that is the LPF. Am I misinterpreting that? I thought that was the frequency where the sub would kick in.

 

[darien87]

All right guys so I got the new AV7005 up and running last night and I have a new issue. There is no ground loop hum but now I have a noticeable buzz in all speakers. It's like the buzz you get from a cheap amp or something. I hear it in all 7 channels so I don't think it's an issue with either amp. The buzz is pretty loud. I can hear it from where I sit which is about 12 feet from the fronts. I had bought XLR cables when I was trying to troubleshoot the ground loop and that is what I used to hook up the XPA-5 last night. But the Onkyo amp is hooked up with RCA's. Could using 2 different types of cables be the issue? All of the components other than the EP4000 are plugged into the Belkin power center. I guess I'll try swapping out the XLR's tonight and see if that helps. The buzz isn't outrageous but it is noticeable and I'm the type that once I notice something like that, it's just going to continue to annoy me.

 

[darien87]

Just called Marantz and they think the issue is the combination of XLR and RCA connections because the XLR's have power to them. Guess I'll try swapping the XPA-5 back to RCA's tonight.

 

[Irvrobinson]

All right guys so I got the new AV7005 up and running last night and I have a new issue. There is no ground loop hum but now I have a noticeable buzz in all speakers. It's like the buzz you get from a cheap amp or something. I hear it in all 7 channels so I don't think it's an issue with either amp. The buzz is pretty loud. I can hear it from where I sit which is about 12 feet from the fronts. I had bought XLR cables when I was trying to troubleshoot the ground loop and that is what I used to hook up the XPA-5 last night. But the Onkyo amp is hooked up with RCA's. Could using 2 different types of cables be the issue? All of the components other than the EP4000 are plugged into the Belkin power center. I guess I'll try swapping out the XLR's tonight and see if that helps. The buzz isn't outrageous but it is noticeable and I'm the type that once I notice something like that, it's just going to continue to annoy me.

You are a far more patient person than I am. The Marantz would be history if I had the problems you're having. My level of patience for poor design or execution is zero.

 

[darien87]

You are a far more patient person than I am. The Marantz would be history if I had the problems you're having. My level of patience for poor design or execution is zero.

Funny. I'm not normally known for my patience. But if it is indeed the cables that are the issue and not the unit itself I'd hate to pass up on what many say is a great pre-pro just because I didn't want to spend some time trouble shooting.

 

[AcuDefTechGuy]

You are a far more patient person than I am. The Marantz would be history if I had the problems you're having. My level of patience for poor design or execution is zero.

Same here.

HISTORY I tell you.

 

[slipperybidness]

Funny. I'm not normally known for my patience. But if it is indeed the cables that are the issue and not the unit itself I'd hate to pass up on what many say is a great pre-pro just because I didn't want to spend some time trouble shooting.

Well, if you can't mix RCA and XLR cables on the unit, then I would consider that a design flaw!

Keep us posted. I drooled over this pre for a long time but I've just come across too many people with complaints or problems. That's really a shame too because it looks like it is a nice performer for most people.

 

[AcuDefTechGuy]

Everyone should just use receivers because you never (correction--- hardly ever) hear any hum from AVR (except for some minor almost inaudible transformer hum).

 

[slipperybidness]

Everyone should just use receivers because you never hear any hum from AVR (except for some minor transformer hum).

I don't know that "never" is accurate, but it seems to be less problematic.

I am very curious if the SR7005 has the same issues as the AV7005

 

[AcuDefTechGuy]

I don't know that "never" is accurate, but it seems to be less problematic.

I am very curious if the SR7005 has the same issues as the AV7005

Only if you hook it up to an amp.

Otherwise, no hum there, just like 99% of all AVR.

 

[j_garcia]

I have XLR for my sub and RCA for everything else with the UMC200. No hum with my XPA-3 or any of the other amps I've used with it or my SR8300 previously.

I'd be curious if the AV7005 uses the same transformer as the SR7005 since the chassis look similar.

 

[darien87]

I gave Emotiva a call for the hell of it. Here's how the call went. Me: "Hi, I recently replaced your UMC-1 with a Marantz preamp and I'm getting a buzz from my speakers." Emotiva Rep: "Is this the AV7005?" Me: "Yes as a matter of fact it is." The tech tells me he gets calls like this all the time. He didn't agree with the Marantz tech that the combination of XLR's and RCA's was the problem. His recommendation was to attach a ground wire from the back of the AV7005 chassis to the screw of the wall outlet. He said this should more effectively ground the processor and should solve the issue. Funny that the guy knew exactly what I was talking about as soon as I said Marantz.

 

[darien87]

Question for the rest of you. For some reason I cannot put a hard return in my posts anymore. I can hit the return button all day and nothing happens. That's why all my posts look like a big run-on sentence. Do any of you know what the issue might be?

 

[AcuDefTechGuy]

Question for the rest of you. For some reason I cannot put a hard return in my posts anymore. I can hit the return button all day and nothing happens. That's why all my posts look like a big run-on sentence. Do any of you know what the issue might be?

Are you using Internet Explorer?

If so (like me), you need to turn on the Compatibility View for all websites.

Menu Bar ---> Tool ---> Compatibility View Setting ---- > display for all sites

 

[Adam]

Question for the rest of you. For some reason I cannot put a hard return in my posts anymore. I can hit the return button all day and nothing happens. That's why all my posts look like a big run-on sentence. Do any of you know what the issue might be?

I answered that when you asked a day or so ago.