RFI in tube system

Hi Folks,
I need help. I recently set up my tube system in my new house and everything was great for a couple of months. Then I started to pick up significant RFI. I can hear a muted radio station coming through my system and static interference. Driving me crazy.

I've been playing around with cables, equipement, etc and found the following: My Shanling SACD player has output levels, so I bypassed the preamp and hooked my CDP directly into my amps. RFI was gone. So it seems that the preamp is the problem. I've switched out my interconnects and power cords and there's no appreciable difference. I've also tried using another outlet with no improvement.

I'm not sure what I'm doing here as I'm not very technologically savvy, so any advice would be appreciated. I've read here about power conditioners. Would they help? Or RFI Filters on my interconnects & power cord? Or is this going to be an expensive hit-or-miss process.

Thanks in advance for any advice.
I'd look into replacing preamp tubes.
Do you have any coax cables near your pre-amp? I had an ARC REF1 that would get noisy if I moved my tuners antenna coax to close to it. Sounded just like a tube getting noisy.
try using rfi chokes. i have a few i'm not using. i'll sell them to you for $1.00 each + shipping. they can be placed over interconnect cables, power cables and speaker cables. in your case, the preamp power cord and interconnect between pre amp and power amp might be a good start.
Try hooking up the pre and power amps normally, with the interconnect that would connect to the CDP in it's usual position(but w/o the CDP). Turn up the volume on the pre(Don't touch the interconnect) . Is the radio signal there? If it is: Turn the volume all the way down, remove the CDP interconnect and turn the volume up again. That should tell you if the most likely antenna in your system is the culprit(the CDP interconnect). Second would be the pre itself. Try some shorting RCA plugs, if that's the case. For instance those mentioned halfway through this article: (http://www.sixmoons.com/audioreviews/acousticrevive/ground.html) If you don't want to spend the $275 on those plugs, here are a couple other suggestions: (http://www.cardas.com/content.php?area=products&content_id=7&pagestring=Accessories&product_id=29) Music Direct, Needle Doctor, Audio Advisor and Galen Carol all sell those. Then there's the cheapest route:(http://www.siteswithstyle.com/VoltSecond/Shorting_plug_rca/shorting_plug.html)
Are any other components plugged into the preamp? Try removing them, so that only the component you are using is connected to the preamp at one time.
Poorly shielded interconnects are often acting as antennae, so try is to replace yours w/the cheap interconnects that typically come w/olds vcrs(2 wires, white, red, & yellow). They sonically are lousy, but they are usually very well shielded because JVC, Sony etc, expect their customers to have many wires often tangled. If they eliminate the trouble, then shop for highly shielded good sounding interconnects.
Physical line of site to radio signal often comes into play, so try moving gear away from windows, and/or turning gear 90degrees, it might help. Cheers,
Thanks for all your helpful advice everyone - and sorry for my delayed response. (My job popped a surprise worktrip on me and I've been out of town for a couple of days.)

Mrtennis, I'll pm you about those rfi chokes. Woudl like to give them a try though I'm using Audio Metallurgys and need to figure out if they'll fit around them.

I'll also try to further isolate the problem as suggested when I get home tonight. In the meantime, I was looking at a PS Audio Duet (I'm on a budget here!) Does anyoen thing that might help reduce the rfi problem?

Thanks again!!!
Don't buy any components to suppress noise until you know what's going on...