[jeffxjet]

I just recently started getting a hum through all 7 speakers. WHen my theater was first put in it was perfectly quiet for 3 years and the last month it has aquired a very loud hum. I went through all the troubleshooting steps and determined that the hum is present any time the preamp is on, with or without any other components. With the preamp off(Rotel RSP1066) there is no hum, even with everything else on. I have concluded it is the preamp causing the hum.


My question is now what do I do? As I said it has been perfect up to this point and just recently got the hum. My quess is that something has failed internally. Can someone explain was might have happened and how I can correct it. Is it something I can do myself? or should I send it in for repairs?


Thanks, Jeff

 

[thebland]

So with all interconnects out and connections to the amplifiers in place you get hum?? Did you try plugging the amplifiers in one at a time into the Preamp to see if it is an interaction with only one of the amps??


It could be a bad interconnect as well (loose solder joint, etc)??? Did you try and ground the preamp chassis to a grounded outlet?? Using any balanced to unbalanced connectors?

 

[jeffxjet]

I didn't ven unplug anything. I just turned them on and off. With everything on but the preamp...no hum. Just the preamp on...hum.


An update, I pulled the rak out from it's hole to get a better look at things and there is no hum at all now. I watched 3 movies and some tv with the rack pulled out and no hum, total silence. Would overheating cause this? My wife is going to bring me home a couple of rack mount fans and we'll see if that does the trick.

 

[thebland]

Overheating would not cause this. If you pulled out and all got better, I suspect a loose cable or failing cable. Move things around and try and get it to comeback..Then try and isolate the source.

 

[jeffxjet]

When I moved the rack, the power cord from the preamp fell out relatively easily. I reseated the power cord firmly and after that I had no more hum. I wonder if that might have been it?


As it stands now there is still no hum.

 

[jeffxjet]

Another update, the hum is back. I checked the power cord and all was normal. I then removed the interconnects and for each speaker that I removed the hum went away. It must be the preamp.


Has something failed in it? Help, the noise is driving me crazy.

 

[thebland]

I would attempt to ground its chassis. Is it unbalalnced? Are the amps balanced? Is the outlet properly grounded (test it)?

 

[jeffxjet]

How do I go about grounding the chassis? I have no idea whether or not they are balanced. I assume the outlet is properly grounded as this problem has only recently occured, and is intermittant.