Help with AC noise please

Hi all, I have a dedicated AC line for my audio, Monster 5100 filter, Quantum symphony conditioner, Nordost Red Dawn interconnects, MIT T2 biwire cables(15'), MF cdpre24, PS audio amp, MF tube buffer, Emminent Tech speakers,
When I put ear close to the speakers I can hear what sounds like something frying in a pan, sort of a crackling sound. It is louder through the left speaker than the right. To make things worse for about two days the left speaker was absolutely silent, with the right speaker only emitting the noise very lightly. I have removed, and relocated all the devices but when the noise is present it stays. I tried rerouting the cable, even lifting them up off the concrete basement floor, but no help. I unplugged the tube buffer, no help. All the equipment is mounted on a verticl rack. I have moved the tube buffer away from the rack. Even with all the lights out I still have it. But then sometimes I don't. When the noise is gone I tried to discern what was different but could not. Does anyone have any ideas? Thanks
Well I disconnected, then reconnected everything while listening in between. I discovered it is the Musical Fidelity tube buffer causing the noise. I called the importer and spoke to a technician. He told me that I should not connect the buffer between the pre-amp and amplifier. He reported that doing so could cause damage to my speakers and/or amp. The reason is that when the buffer is first powered up a DC spike is created that is passed through the output of the buffer. If the amp is already on this spike could damage the amp, blow a fuse, or blow out speaker drivers. The tech recommended mounting the buffer in the tape loop of the CD Pre24. I did this, and found that the noise I was getting through my speakers was almost completely eliminated. The left speaker is now dead quiet, while the right has just a hint of noise with the volume set medium high(which is about the limit for my room). I also noticed a little more freedom in the area of dynamic shifts from the amp. This was confirmed by viewing the amp meter on my line conditioner. Without the tube buffer the music is clear,detailed but a bit flat. The buffer adds that bit of livelyness to the sound making it sound more real. Therefore I will continue to use it. On my system the bass does not seem to be adversely affected. Thanks to everyone for their help.
Wow,that stinks.I had the buffer in as you did.
My buffer is long gone now but I wouldnt get another one.
I have a tubed SACD player now, so I doubt I would get any benefit from one.
It made my old Sony SACD player sound better in some aspects though.
I think the really important part of this "problem" is that it may not be a problem at all. You said:

" When I put ear close to the speakers I can hear what sounds like something frying in a pan"

If you had to get that close to the speaker to hear it, and if the noise does not increase when you turn up the volume, then don't worry about it. Just about every amp, tube or transistor, can send a little bit of noise into the speaker. Tubes always send a little noise, that increases with age, which is one of the things that can tell you when to replace them.

Don't worry about it.
Thanks again everyone for your responses.
Golden Ears I think you are right about not worrying about it too much. I am pretty happy with the sound the system is providing me. It is the best I have had to date. It was just one of those things that you can get carried away with trying to eliminate only to discover that in the end it really didn't make any audible difference when sitting in the listening position. At first I was a bit concerned, but now that I am sure it's comming from the tube buffer, well I can live with it. I suppose it might be covering some low level detail, but I really can't discern anything. Perhaps the background would be blacker, who knows. I like the way the system sounds and that in the end is all that matters. In a few years I will probably get the upgrade bug again anyway!!