RB 1090 - Buzzing Noise

[Brent Briscoe]

Hello.

Just noticed this forum the other day. Great idea and people seem very knowledgeable.

I am upgrading to a Rotel system. Last week I purchased the RB 1090 amp to drive my PSB Stratus Golds. It is a great amp which sounds wonderful and looks great in silver. It reminds me of one of the bigger silver Classe amps (at a considerably lower cost). I currently use a receiver as the peamp and I just know its holding back the 1090 from its full potential. I have the RSP 1066 and an RMB 1075 on order to round out my HT system and to drive a pair of speakers in a second room.

Unfortunately I am getting a buzzing noise (ground loop?) from the amp with both just the speakers connected and the whole system connected. When putting my ear up to the amp it sounds as quiet as any other good amp. I have had other good amps in my system (Anthem, Sim Audio) without any noise. I have tried swapping interconnects and plugging into a seperate circuit but the noise persists.

I don't believe the amp is mechanically faulty so I am wondering how to fix this. I noticed another forum member who posted that he had a similar problem with his RMB 1095.

I would appreciate any possible solutions people might have.

Once I get my 1066 connected I will give you my impressions on how the system stacks up.

Thanks alot
Brent

[Arnold van Oostrum]

Low buzzing is probably, as you already have guessed, a ground loop problem. Best way to deal is disconnect everything. Listen to the RB-1090 with only the speakers connected. Is it quiet, hook up one item, like the RSP-1066. Still quiet, go on and find out this way what causes the ground loop.

Sometimes turning the powerswitch different in the outlet (switching + and - ) will also help. All units should have the power + and - attached the same way. So try switching.

[Brent Briscoe]

Thanks Arnold.

When I bought the amp I only connected it to the speakers with nothing else connected and the buzzing was there.

[Andrew Pratt]

Welcome to the forum!

As arnold said it sounds like a gound loop hum. I'm surprised though that you still heard it when only the speakers were connected...just to clarify there were not interconnects connected at this time right?

Do you have cable or a Sat. Dish in your system? If so how is the cable feed grounded? Most ground loops are casued by cable or sat dishes not been grounded properly. Ideally ground cables should be connected to the cold water pipes...if its connected to the panels ground wire try the cold water pipe to see if that helps.

[Arnold van Oostrum]

When I bought the amp I only connected it to the speakers with nothing else connected and the buzzing was there.

If you hook up your speakers to your RMB-1075, is the buzzing than gone? If not, your speakers or speakercables are picking up some signal. If the buzzing is gone with your RMB-1075, I say bring the RB-1090 back.

[LEVESQUE]

Don't bring the amp back please! Just go read this

http://www.hometheaterforum.com/htforum/showthread.php?s=&threadid=101533&highlight=levesque

I had the exact same problem. It was the RECEIVER. It was a Yamaha RX-V3200. The day I had the RSP-1066 instead, POUF, problem gone. No noise anymore. I bet it's an internal grounding issue or a difference of potentials between the receiver and the amp. Just try the Rotel pre-amp.

[Brent Briscoe]

Thanks to everyone for there feedback. I think I found what is causing most of the problem. I disconnected everything and also unplugged all components from the AC sockets. It appears to be my external line doubler causing 80% of the problem. When it is unplugged from the AC there is just a tiny bit of buzzing which is inaudible from the listening position. Fortunately my gear is built into the wall which backs on to my workshop and I can simply plug my line doubler into a heavy duty extension cord plugged into a different receptacle.

And as Levesque mentioned maybe inserting the 1066 will help. I'll let you know how it all works out.

Thanks again for everyones help.

Cheers
Brent