Idea to reduce RFI

If you want to eliminate an RF interference problem, then you must take the system completely, totally apart, then add each component to the system one at a time to see the point at which the RFI appears. That is, start with just power amp and speakers. Add the preamp. Add each source, one at a time. And so on. Always fight the problem with the simplest possible system that exhibits it.

Other things about RF . . . first, it doesn't care which is an input and which is an output. Any wire of any kind that goes into or or out of your components' metal boxes can bring RF with it. Second, if you can hear the audio signal (modulation), it's an AM transmitter, not TV, or FM, or communications equipment (exceptions being some amateur radio, CB, and airplane-to-tower). And third, the 'balanced' nature of balanced interconnects have no effect on RFI -- very few balanced input stages have much common-mode rejection above 3KHz or so.

Also, unshielded interconnects are really asking for RF problems . . . that's why they pretty much don't exist outside the world of small-market specialty audio. Ferrite (torroid) coils on cables right next to the connectors can help . . . but they usually work best at frequencies quite a bit higher than the AM broadcast band. In your case, I'd start by shielded interconnects, making sure that your electrical outlets are properly wired and grounded, and making sure that none of your equipment has loose RCA connectors.

>> That is, start with just power amp and speakers.
Now, how does Milen007 get music to play thru the speakers? Run the CDP directly into the power amp?

Uh, er, you don't LEAVE the system this way for listening to music. You stick your ear by the speaker to see if, in the original poster's case, the offending "radio channel" can be heard. If it can, then the interference MUST be solved in this configuration BEFORE it can be reliably solved in a more complex one.

the FM signals are somewhat AM. So, the possibility of catching a FM station thru Milen007's system is quite real.

Nope. FM interefence on baseband audio electronics is manifested mainly has hum and buzz, that changes in intensity and timbre as cables are moved around.

>> very few balanced input stages have much common-mode
>> rejection above 3KHz or so.
Another terribly ignorant statement!!

Whatever, dude. Actually, 3KHz is even quite optimistic, especially for active balanced inputs -- most I've measured deteriorate up from 60Hz by at least a single-order slope.

For more information on the subject, I recommend Bill Whitlock's excellent papers (available at jensentransformers.com), which I agree with the vast majority of. I also highly respect the work of Douglas Self and recommend reading all of his stuff . . . even though on this particular subject I differ with his conclusions.