White Noise


Can anyone help me eliminate the white noise coming through my front speakers when I use HT bypass mode. I have a Marantz SR 5011 AV receiver running my center and rears speakers. The Marantz is connected to my Jeff Rowland Corus preamp because I want my Jeff Rowland amp to drive my front speakers when watching movies/TV. When I'm listening to music through my 2-channel everything is dead silent. When I'm watching movies or TV and employ the HT bypass I hear a significant amount of white noise coming through my front speakers. Can anyone tell me why and how to eliminate it?
ricred1
Does this the noise happen only when the HT receiver is on? If so, it's that your receiver has too much noise.

Best,

Erik
Yes, only when the HT receiver is on. Any suggestions for an AV receiver to drive my center and rear speakers?

Quick question - is this white noise a "hiss" or a "buzz" type of sound? If it’s a buzz type of sound, that means you have some sort of ground loop problem going on. If it’s a hiss type of sound, then it’s a problem with gain and receiver signal-to-noise / voltage output (see further below).

One thing to check is to make sure that both the receiver and the Jeff Rowland preamp are both on the same phase A/C circuit. Most houses today have two phases (since they support 240V circuits like oven, etc.). If both devices are plugged into different outlets, it can be difficult to determine if they are on the same phase. Having 2 devices on different A/C phases can cause noise (probably even the ground loop noise).

Otherwise, I agree with Eric in that the receiver could be producing a lot of gain noise. When your Jeff Rowland is in unity gain mode (home theater bypass), it is sending the signal through at full gain (i.e. there is no volume attenuation). This means it is amplifying the incoming signal greatly (which includes anything including background hiss that is in the source). This was actually a notorious problem in car stereo systems where most of the gain was at the amp side and the source/deck was only sending a very low voltage audio signal. This was addressed with decks that had a higher voltage output level.

A work around could be to take that input off "home theater bypass" and turn the Jeff Rowland volume all the way down. Then go into the Marantz speaker configuration menu and turn the front left/right speakers up all the way. Then do a test signal for center channel and left/right. Turn the Jeff Rowland up until the speakers are calibrated properly. You are essentially forcing the Marantz to output a higher voltage for the actual sound signal and reducing the effect of the background noise/hiss. The downside here is that you’ll have to set the Jeff Rowland to that exact volume whenever you want to watch a movie.

Check your interconnects to make sure they have good shielding and that the shield on each side of the interconnect are wired (you can use a continuity tester or multi-meter to test this). This can affect noise. I don’t know of a different receiver that would generate less noise than the Marantz. You’ll just have to test/experiment.

auxinput,

Thanks so much for the detailed response. It's definitely a hiss and not a buzz. The Corus and Marantz are plugged into the same Torus power conditioner. I'm using Audioquest Golden Gate interconnect cable(will getting better cable help). I use Wireworld Silver Eclipse 7 for my 2-channel.
I don't think getting a better cable will help because the cable will still transmit whatever is in the signal (including the hiss). 
auxinput,

Thanks, I'll try your work around suggestion tomorrow. I reached out to Rowland to see what they suggest. They're very helpful and should be able to give me some advice.
I solved the white noise by replacing the stock power cord with a 6' Audioquest NRG-2 power cord. The power cord reduced the noise by 95%.
That's very interesting, ricred1.
I thought I solved my white noise problem,  but I didn't. I changed to separate AV components. I sold the Marantz SR5011. Now I have a Marantz AV 7002 mkII and a ATI 3-channel amp. When using my HT bypass on my Corus preamp, I hear a lot of white noise. It doesn't exist in any other operation, only when I select the bypass input. Please, please someone help. I'm using Audioquest shielded RCA interconnect cables. Will balanced cables help? HELP!
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Thanks bob_reynolds,

When I initially contacted Jeff Rowland they said the issue was with the noise floor of my Marantz SR5011 AVR. I sold the SR5011 and now have a Marantz 7002 mkII AV preamp and ATI amp. I'm experiencing the same problem and it sounds worst with the separates. I contacted Jeff Rowland again via email and I'm waiting for a response. It seems to me that the Rowland output is to high when HT bypass is selected. I know Jeff Rowland was attending the recent High-end show and someone should contact me in a couple of days. Their customer service has always been great.
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I fixed it!
1) I reached out to Marantz today and for the first time they told me to run a wire from the ground on back of the 7002 mk II to a screw on the chassis. That reduced some of the noise.

bob_reynolds,
2) I took your advice...THANKS! I borrowed a balanced cable and reassigned the bypass to a balanced input. DEAD SILENT!  
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Initially I only added the ground wire. It reduced much of the noise; however noise was still audible. After I changed to the XLR cable it was dead silent. I must admit the gain seems a little lower and I will run audesey again.