[vanderstephen]

Hi,
I have a question about noise that I am hearing from my 2 main speakers while watching movies. It's loud enough for the wife to notice it and question it. It's loud enough to notice it on quiet passages. It's not noticeable during the majority of the time we are watching a movie, but I do think I am cutting up the volume an extra few db to compensate.
I have a 2 channel system for listening to vinyl (Odyssey amp, Odyssey preamp, Sutherland phono preamp). I have an Integra receiver for theater processing, powering surrounds and the center. The receiver is integrated into the 2-channel system into one of the line inputs (no HT bypass) using the method of having the volume way up on the preamp and controlling the HT volume through the receiver - the Odyssey amp is powering the front two speakers this way. The buzz is non-existent when the receiver is off. Turn it on, the buzz starts, then when i cut on the projector, the buzz gets a tad louder.
I played around with cables a lot today and here's what I've noticed, but I don't know what the solution is:
- Receiver off, playing records through the 2 channel system yields no buzzing sound. Plays great as one would hope for. I can have all 2 channel gear on with the volume control at the 12 o'clock position, needle up, and hear only the slightest noise with my ear up to the speaker - nothing noticeable from the seating position.
- Next test was removing the 2 channel system from the equation and connecting the front main speakers directly to the receiver. Also no noise. Speakers are dead quiet with the receiver connected directly to the main speakers and the 2 channel system removed from the equation. It just doesn't sound nearly as good playing music through the amps built into the receiver as it does to play music through the Odyssey amp.
- Another test. I changed from one line level input on the preamp to the tape input. I think that may have slightly helped with the noise, but not sure - not enough to say problem solved.
- Another test. I removed the preamp from the equation and connected the 2 channel amp to the pre-outs for the front to two speakers on the receiver. The buzz came back. My 2 channel preamp appears to not be a factor in the noise. It seems to me that the issue is just tied to using the pre-outs on the receiver. Is this a common issue? Or is there something else that is easy to check?
Thanks!

[bladesmith]

Is the noise present in btwn songs on a CD..?

[vanderstephen]

Bladesmith,
I don't have a CD player, only a turntable, so I can't answer your question directly. However, I can say that the noise is present rather I have the input on my 2 channel preamp set to my phono preamp or if I have it set to the input that my receiver is connected through... although that noise goes away when I turn my receiver off.

[Speedskater]

Is the system connected to the internet, cable or satellite TV or other entertainment systems?

[WGH]

My stereo/home theater setup resembles yours with the pre-amp and amp used for both stereo and L&R theater channels. Does the Odyssey have a chassis ground switch? I have never found them to do anything but manufacturer's include them in case there is a ground loop condition, all my electronics have them. A couple of shielded power cords solved my bzzzz, hummm problem.

I also re-calibrated the home theater to get rid of the last little bit of noise. Lower the pre-amp volume by 1/3, then re-calibrate the center and surround speakers to match the new stereo speakers volume. The center and surrounds may end up at +5 or more.

[vanderstephen]

Speedskater, The receiver has a bluray disc player connected to it and a Roku Ultra. They are both connected with HDMI cables. They stream wirelessly though.

WGH, I checked the back of the Odyssey preamp and amp and did not see a ground switch on either. The preamp appears to have a place to connect a ground wire, but I think that's for a turntable. Judging by the codes on the power cables, it does not appear that any are shielded, so that sounds like a fairly inexpensive option to try. I'll also look at lowering the preamp volume as you've noted and hope that still allows me to get enough volume for watching movies. That part may wait until next weekend or after. Between the time of my original post and now, my HVAC stopped working where that is located so I've unplugged anything that will needlessly generate any sort of extra heat.

Thanks for all of the questions and input thus far. I'll look forward to hopefully getting this resolved after the HVAC is fixed.

[tvyankee]

Hey.

Unplug everything.  Start by only having a speaker cable connected to one speaker and that's it. Do not connect the other speaker.  Listen for hum if no hum then connect 2ch pre one rca or xlr at a time and listen for hum.  If no hum continue to second rca if no hum continue.

Then take your av receiver and do the same.  Take front preout one at a time and connect those as well and listen for hum the whole time while do the hookup. If you take this one wire at a time you find the hum.

Also what speedskater is saying is that cable and satellite systems have there own grounds that are not the same ground as you house ground and there is difference between the 2 and that causes the hum. They make isolating devices for that sought of thing if you need it.

Good luck let me know if you have more questions.

[tvyankee]

Btw always make sure you turn preamp on first and then turn your amp on so you dont send voltage into amp while it's on and get that nice poping sound from your speakers. Also when you turn off do the opposite, turn amp off first then pre.

[skunark]

Are you using more than one power-strip?  Outlets?   If so try to have everything on the same power-strip.  If you have subs, might test with them disconnected, and as mentioned above same should go with any device that takes a coax input to help narrow down the issue.