Buzzing from speakers. Where is it coming from?


I can hear buzzing from the speakers's tweeter when I put my ears up to it. Can't hear it from the listening positon. Speakers are Vienna Acoustics connected to a Mcintosh MC402 amp via a Pionner reciever as a pre/pro. The Mcintosh is directly plugged into a wall outlet. The Pioneer is plugged into a Monster power conditioner. I have tried just turning on the Mcintosh with no signal and it still has a buzz. Then tried plugging it into the line conditioner and still buzzing. Lastly, I tried connecting the speaker to the Pioneer and still has buzzing but slightly quieter. The buzzing occures with all speakers. The Mcintosh powers the fronts. The Pioneers powers the center and rears. Any suggetions?
Thanks
vuongd
Vern,
I don't understand? Disconnect speakers from amp and listen for noise! Good trick.

I'll agree with one thing, which I hope is what you MEANT, if not said.

disconnect everything but speakers to amp. Even the interconnects. If the hiss disappears, start adding stuff back one component at a time. You have to go at this systematically to find the culprit. Process of elimination may be tedious, but it should yield a result.

No 'usual' cause. It is what it is. maybe the sub, maybe the sat dish. Maybe the neighbors microwave! (kidding on last)

Do you have an outlet tester? Use it. cheap check.
Don't lift grounds. Find the hiss-maker, first.
So I think I know where the buzzing is coming from. I first started to disconnect the RCA's to the MAC. Dead silent. So buzz is not coming from the amp. Second, I reconnected the RCA's to the MAC and then unplugged the Pionner receiver from the Monster line conditioner. Plugged the receiver into the wall outlet and got a hissing instead of the buzzing. I believe the "hissing" is normal. So replugged the receiver back into the line conditioner and again got the buzzing. I also noted that I could hear an electronic buzzing comining directly from the conditioner. So it must be it. Does this sound reasonable to you guys?
I'm sorry, At this point I don't know what is or isn't connected to what! My bad.

Let me see if I've got this straight.
Mac's only to speakers. No problem?

How much hissing from Pioneer? Does it change with vol? How far away can you hear it at quiet time?

What kind of power conditioner? A 'buzzing' from the conditioner I would think to be NOT normal. Is the buzzing from the PC and speakers the same frequency?

I hope some of the others show up again and have another shot at this, with some mo-better info.......
Magfan,
Very slight hissing from the Pioneer. I didn't try turning up the volume and can only be heard if you put your ears directly up to the tweeter. Yes the buzzing does seem to sound about the same between the line conditioner and the speakers. The line conditioner is from Monster.