I'm actually on my second Marantz unit for this. Started with a 7010 now on a 7011. A few months ago I added atmos speakers to my setup. Right away I noticed I had crackling out of my right atmos speaker. I swapped the speaker wires on the amp side and got the crackling to travel to another speaker. Oddly enough, I could make the crackling go away briefly by turning the receiver off and on a few times or raising the volume really loud on the test tone menu and then bringing it down. You could hear it crackle until it got to about 80 where it became a steady sound and then I could lower it down to 55 or 60 and it would be fine for a bit but it would always come back.
I sent it out for service. They tried to fix it but I got it back and it had a different worse issue (Went into protect mode within minutes). Now I know my speakers aren't easy to drive, but they shouldn't have immediately caused it to go into protect mode. I could not get the receiver to turn on for more than ten minutes at a time. My left and right Martin Logan Theos speakers are being run off a Rotel power amp so my Marantz doesn't have to worry about those. My Marantz is powering an electrostatic center channel and six Martin Logan Motion speakers (Four 15s and two 2is). So I sent it out for service again and this time got back a refurb 7011.
Thought all was great. Ran audyssey watched some movies, played some games, awesome. Then all of a sudden I started hearing the crackling again but this time out of the surround back right speaker. Again same thing I could turn the amp off and on and it would go away or I could raise the volume really loud and then bring it down and I would hear the crackle until I was at 80 or so when it would give me a steady tone in the test tone menu.
Is there something I'm missing here? I can't imagine two separate receivers that are two separate models would give me the same problem (different amp channels). Any ideas as to what may be causing this and why raising the volume high gets the speaker to stop crackling for a short period of time? It's driving me nuts.
It certainly sounds as if the receivers are the problem.
It sounds as if you have to turn up the volume to create a spark to make a contact. The most likely culprit is relays.
The bigger issue is receivers. I just do not believe you can cram all that processing, amps and power supplies into one case. It is just begging for trouble. I have never liked receivers and don't use them. I know a lot disagree with me, but I consider them low end troublesome devices.
You are driving a center electrostatic. They are a troublesome load. I would not personally connect any electrostatic speaker to a receiver. All of your speakers have low impedance. I note that Marantz have now stopped giving ratings for 4 ohm loads. That really tells me what I suspect that receiver amps are now junkier than previously.
I think you have to consider biting the bullet and going the separate route, with pre/pro and power amps.