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?
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Thanks Elizabeth. I only noticed it yesterday when getting close to the speakers to change out a disc. Makes me feel better now.
When you were changing a disc? How close were you to the speakers when you noticed the sound? Is it a hiss or a buzz? Is it equal level in each channel?
If it's a hiss only heard an inch or two from the tweeter then I would agree with Elizabeth. If it's a buzz then you might start checking tubes (the MC402 is a tube amp, right?).
Tim, it's more of a buzz and it can only be heard when my ears are right up to the tweeter. It's equal on both channels. The amp is a SS not tube.
My stuff is dead quiet. PSAudio 'd' amp to some panels.

you have to turn it up to 'obscene' to hear anything with no source on/selected.
In that case I agree with Elizabeth.
BTW, I'm using class D amps also. They are dead quiet when idle.
If it's a buzz then it's a ground loop of some sort. Or if as you say it's pretty constant I'd look at things like light dimmers, or something else throwing a lot of noise, cable boxes are notorious for that sort of thing.
Yes, it is close to my sat. box. I can't move it out of the way though. Thanks everyone!!
I'm sorry, I don't mean to mock anybody, but people go to incredible lengths to optimize and choose cables, connectors room treatments, racks and any of the hundred and one things affecting sound.
Some items are pretty...shall I say....esoteric? The differences in cables, some would say is pretty small while others call it titanic.
I'd say that any tweeter hiss is on the intolerable side.
A BUZZ from the tweeter? Shouldn't that be a HISS? I'd expect the BUZZ thru the woofer.

Start going thru the list by first disconnecting everything and if the hiss goes away, reconnect 1 item at a time till it returns.

This is the worst thing to track down. I'm betting on the Sat Box, which has lots of RF circuitry and are notorious for spewing it everywhere. My sat box is a good 3 or 4 feet from anything stereo related.
Ground loop. Usually cause by speakers. To test disconnect speakers from amp. Turn on amp if no hiss it is the speakers. If it hisses IT IS THE AMP. My bet is to get a high quality outlet like a Levitron or Hubbell 20 amp(set you back $8 for a double outlet) and this will cure the problem. Houses put 89 cent outlets on houses these days.If not disconnect everything and introduce one componet at a time. USUALLY these are caused by subwoofers
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.......
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.
Has the conditioner absorbed a few 'zaps'?
Can you swap it out for something.....anything else?

Ear-up-to-tweeter noise? Most people would ignore that, I'm afraid. If it responds to vol control, it is 'part' of the Pioneer. As to if it is 'defective', that's the question......
YES un connect speakers from amp. LISTEN TO AMP TURNED ON. If no buzz-no problem with amp