Axiom Home Page Forums General Discussion Technical Questions Are the demons back JohnK? EP600 strange issue....

Ok, we are down in the basement right now as a severe storm is moving through central Iowa. The kids are in the other room watching something on the extra tv and my wife is sorting stuff in our storage room for goodwill.

I am near the HT area just cruising the internet on my laptop via wireless connection. I have been hearing a faint thump thump about every 10-20 seconds or so and just passed it off for some thunder in the distance.

I looked out the walkout door and there is no activity right now. So I walked over to my ep600 and sure enough, every once in awhile there is a quick thump thump and sometimes more like thumpity thump thumptiy thump thump.

What the heck is going on? All of my AV equipment is turned off. Well, the 600 is always on, but my receiver, sms-1, etc. are turned off.

What the heck could be causing short quick bursts of thump thump? This is two weird.

Randy

Yup, Randy, it's time to call the priest again. By the way, when you ordered the EP600 did you accidentally click on the demon portal option?

Unplug the LFE cable. Does the thumpity thump thump go away?

Well, I did turn the main power switch on the back of the sub off/on and it seemed to have stopped. Almost like energy was stored up and I released it.

I just ran down again, and still hear a very faint thump thump now and then. Is it possible if it is lightning outside that the ep600 could be picking up that energy, or could air preassure because of a storm move the woofer in/out enough to cause a faint thump. It is almost like if you took your finger and tap the driver cone.

Mojo, I'll try the coax cable next...

I just went down there and it still does it when the coax line in is unplugged. If I turn off the amp on the sub it stops.

What is strange is when I first heard it I was like 20feet away and it was much louder. After powering off/on the switch the first time it pretty much went away. I have to get my ear down right in front of the woofer now to hear an occasional bump bump versus the original thump thump.

I hate when I discover these things. argggg

At least you've eliminated conducted or radiated interference on your sub cable. So it appears to be coming from the power outlet.

What other equipment is plugged into that same circuit that is powering the sub? Try unplugging (not just turning off) all equipment that is on that same circuit. Then see if it stops. If it does, methodically turn each piece of equipment on and monitor to see if the thump comes back. This way you may be able to isolate it to a specific appliance.

Yes Randy, they're back and will soon also be at the Odyssey. Again, if your minister doesn't do that sort of thing a priest can perform the exorcism(with a reasonable contribution to the church, of course).

Okay, now I'm not kidding. About a month after I got my EP500 I heard an intermittent thumping sound that I at first thought was coming from the wall or roof. A couple years ago I'd shot a 'coon off the roof, so thinking maybe another one was planning an invasion, I was about to grab one of my guns. In trying to locate the sound better, however, I happened to listen near the sub(the system was off)and discovered that it appeared to be coming from there. So I turned the sub amp completely off and the thumping immediately stopped. Thinking of you, I wanted to immediately sprinkle it with holy water, but had none at the moment, so I kept the sub amp off for maybe 12 hours. When I turned it back on there was no thumping and there's been no repeat for the past 6 months.

I couldn't figure it out, but since it didn't re-occur, I wasn't concerned. Leave yours off for a while to see if some magic occurs.

When I tested the Line-In cable, I reached around the sub and just unplugged it, holding it about an inch away from the line-in connection. Unless sound can jump an inch through the air, I would say that is not it...

I have a dedicated 20amp breaker using 12-2 wire for my HT equipment, so the only other items would be my AV equipment. All the power was shut off by the main switches for everything except the amps that I leave on all the time.

I can test some more later this week. It is just strange that it was so much louder prior to me powering off/on the sub, now it is pretty hard to hear unless your real close, and even then it is very very faint now.

John, just read your post, thanks for the advice. I'm sure our Lutheran Pastor would be glad to stop by anytime.

Your similar description is exactly what I'm experiencing. I leave my 600 on all the time. It was not until tonight during the storm that I heard the louder thump thump from like 20 feet away.

I passed it off for thunder in the distance or the dog upstairs jumping off the bed above the HT area. I soon discovered as you did it was the 600. Just powering it off/on for a few seconds dramatically reduced the thump.

Funny thing, when I first turned the switch off, I heard a loud thump. It was almost like I released some electrical charge that was built up over time.

I'm glad the demons have decided to migrate via the internet to your home from Iowa.

Turning off the switches of the A/V gear doesn't physically disconnect your equipment from the mains. Your equipment may be dumping harmonics onto your AC wiring. Maybe it's the flux capacitors in the Odyssey that are finally broken in . Unplug them instead and play "Sherlock Holmes".

During thunderstorms, electrical systems experience large ground currents and transient voltages. These do make their way to the distribution system. Depending on how the power supply of the 600 is designed, it may be influenced by these transients.