Loud background noise: cables picking up RF?

"I get the noise as soon as my preamp and amp are engaged, whether or not I have a source hooked up. Can I buy a cheap AV-style IC from Best Buy and and see if the cables are the problem, or are those low-end IC's they sell really shielded? Are the power cords also a likely culprit?"

In the previous post I did not address this part of your post. The power cords are not the problem. The wire feeding your outlets will still be there and that is not shielded. RFI filters immediately inside your preamp and amp should take care of that anyway unless it is of extremely large magnitude. In which case you may need an external RFI filter. Again - using an oscilloscope to troubleshoot will make life much easier. As to ic's picking it up - maybe. Any shielded IC should work fine. What is important is that the shield is complete and terminated correctly. Make a pair of IC's yourself, terminate the cable so that only one end of the shield will be connected to ground when it is hooked up - make that end the source end in each case. Radio shack best buy or whatever - no need to go to an expensive cable. To minimize any problems as to coverage of the shield (if you are using a mesh vs foil shield)- avoid sharp kinks in the cable. As a quick check- try adjusting the position of the cables that you do have hooked up now. The effectiveness of an antenna for a given signal depends on its orientation - if you start moving the ic's while listening - as if adjusting an antenna - and you hear a change - then yes, your ic's are definitely picking up the interference.

You've gotten lots of great advice here. Please follow up to let us know what you figure out.

If the ICs are a big help, then you're in one of those situations where almost every improvement you make will be noticeable. If that's the case, then I'd recommend going fully balanced if your pre-amp doesn't already allow it. Think of RFI with every IC and cord selection and consider putting a conditioner in the line. These improvements will be small relative to fixing your initial problem; however, when your bathed in RFI then plugging every hole is important.

Dave

You are not hearing transmitted RF through your speakers - you cannot hear RF and your speakers cannot reproduce it - outside the frequency range for both.

His audio system can work like an antenna and receiver. And long speaker cables can work as an antenna and the transmitted RF will be heard through the speakers.
Example
You might want to check out the archives here on Agon.

I do think in the case of Dawgcatching if the sound he is hearing from his speakers is static, just my 2 cents, I don not think it is caused from the communication tower antennas. But no guarantees....

Static can also be caused from a HV cold solder joint or point on a circuit board with in the preamp or the power Amp. Could be a bad connection on a tube socket for example.

Unless Dawgcatching joins in the discussion it will be very hard to help diagnose the problem.

No Jea48 you are incorrect - his speaker wire will not act as an antenna that causes transmitted RF to be heard through his speaker - that makes absolutely no sense - if that were the case he would be hearing RF all the time, with or without his amplifier on or connected. In every system on this planet the speaker wire is past the amplifier not before it.

Thanks for the advice. Describing the sound: I get a whistling sound when my CDP is engaged and I am on that input (probably some sort of DC leaking there) and a general hum when I turn the amp and preamp on together (not present when the amp only is activated). I am also getting a static background noise when I have my preamp hooked up (a Herron) but the preamp was just back at the factory and checked out fine. Perhaps it has something to do with the preamp tubes picking up something out of the air, although my backup preamp (EE Minimax, also tubed) isn't picking it up, and is much quieter.

The static is pretty constant: the whistling noise and hum comes and goes, although I usually hear the Whistling around 15 minutes into listening. It tends to diminish over time, but can still be heard at high volumes.

I should have posted this earlier: I am headed out on vacation on Monday, so I won't get time to start troubleshooting the system until I get back.