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Buzz/hum through speakers

When I turn on my system, I get a buzz/hum through all the speakers. I have everything hooked through my Furman line conditioner. I have plugged my amp directly throught the wall outlet with only speakers attached to the amp and no noise. I have disconnected everything from the line conditioner one by one and only makes the noise when the pre and amp are turned on together. My dealer gave me something called Hum X and when I plugged the Furman into the Hum X, noise still there, it's only when I plug the Hum X to the back of the Furman and plug the amp into the Hum X, the noise is gone. Is there any way to get rid of the noise without using Hum X? If I can't get rid of the noise with Hum X, is Hum X holding back the full potential of the amp?
kalbi23
12 responses Add your response
zd542
5,339 posts
 
Try it just on the preamp.
kalbi23 OP
58 posts
 
I have just tried it on the pre and still the same.
Post removed 
dms1
13 posts
 
You should not plug your amp into the Hum X is it is only rated at 6 amps and will restrict your power amp.

Have you tried changing the interconnects from your preamp to your amp? Sometimes a connection goes bad causing the hum. I found many years back a very good source of info on tracking down hum problems were some white papers on the Jensen transformer website.

If nothing else works you may have to change power conditioners. I have had good luck with several Furman conditioners but when I tried several other brands in my home theater system I got hum. Sometimes you just have to experiment.

Good luck.
bigshutterbug
382 posts
 
Try grounding the chassis of the amp to the pre-amp, using a thin piece of 18-22 gauge wire. Wrap the bare wire ends around the head of a chassis screw, then tighten.
kalbi23 OP
58 posts
 
Ok, here is where I am at. I have 4 sources plugged into my pre, a PS3, TV, Oppo HDMI and Oppo analog. I can leave the TV plugged in via HDMI, but I have to disconnect the HDMI for the PS3, Oppo HDMI and Oppo analog for the buzzing to go away. Does this mean the pre is bad or do I need new analog and HDMI cables? Thank you guys for all your help.
zd542
5,339 posts
 
Call The Cable Company (www.fatwyre.com). They're very good with these type of problems. If they recommend something, they will let you try it first so you know if its the right thing for you. I've been using them for years and find them to be very honest. They should know exactly what to do for you.
josephaud
41 posts
 
You probably have a ground loop. If you disconnect the cable feed to the TV set and the hum drops away that would confirm it. A ground loop is caused when there's a difference in ground potential between your cable and electrical grounds. You can solve it by breaking the ground connection at either end. On the cable side you can use a pair of baluns 75 ohm to 300 ohm & 300 ohm to 75 ohm wired back to back to lift the ground there. Or use a 3 prong to 2 prong ground lifter on the electrical side to break the connection there. Also make sure the preamp is not stacked directly on top of the power amp as it may pick up induced hum from the power transformer.
Post removed 
kalbi23 OP
58 posts
 
Ok, called fatwyre, and they were no help. Basically told me to call the electrician, I guess that is my last resort. I've disconnected everything that is on the same circuit and the cable from the wall, but the buzz/hum remains. The only way the buzz/hum disappears is when I disconnect all components from the pre. I do have my pre stacked on top of the amp, put it side by side instead and the buzz remains, is it still too close? I would have to buy new XLRs if I need it to be further apart. Any other thoughts or suggestions? Thanks again everyone.
kalbi23 OP
58 posts
 
Sorry Mental, I don't know what "ticked" means. The PS3 and Oppo is connected via HDMI, for 2 channel I have interconnects connected from the Oppo to pre to the CD section.
kalbi23 OP
58 posts
 
I replaced the pre with another AV7701, the hum is still there. I called Marantz and the support rep said, my amp is faulty. I asked, when I use my Oppo as the pre, how come the hum isnt there? The rep had no explanation. I went back to my store and asked if I could borrow a different pre, borrowed the AV8801. No noise what so ever from the speakers. Does this mean the AV7701 has a internal grounding issue? Thoughts? Thanks for all your help to everyone.
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