Idea to reduce RFI

I had a similar problem with my turntable and switched phono cables and the RFI disappeared just like that. So it may be as simple as changing an interconnect or two in your system.

BTW, I tried ferrite clamps on various cables and it never did anything.

well, at one point my brother had the same issue - FM radio channel playing thru his speakers! He solved it by using XLR interconnects. The balanced interconnects have the FM channel on both + & - wires but of opposite polarity thereby effectively cancelling the FM signal. He now does not have that issue any more.

Shielded cable is good but remember that it adds extra capacitance which reduces the cable's bandwidth + adds a cap load to the amp. Sonics could/will change. In some cases (maybe yours) you might have no choice.
Power conditioner: I've found that the best solution is to not use one! They always change the sonics for the worse (the ones I tried). However, YMMV.

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.

>> 06-21-08: Kirkus
>> 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.
good advice, in general.

>> 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? If yes, the 2V CDP will most likely saturate the power amp input stage & cause high SPL (distorted) sound. He could buy some in-line attenuators but then that's costing Milen007, which he might not be willing to do (?)

>> Second, if you can hear the audio signal (modulation),
>> it's an AM transmitter, not TV, or FM,
Theoretically you are correct - FM is constant envelope modulation. However, in really life due to interference from buildings, foliage, terrain, etc the FM signals are somewhat AM. So, the possibility of catching a FM station thru Milen007's system is quite real.

>> And third, the 'balanced' nature of balanced
>> interconnects have no effect on RFI
this statement could NOT be further from the truth!! It seems to be a statement you have made out of total ignorance in the matter.
Go look at any RF layout whether it is I.C. layout or PC board layout & you will see differential circuits used exclusively! Differential circuits ARE balanced circuits. It is one very important way to curb RFI.

>> very few balanced input stages have much common-mode
>> rejection above 3KHz or so.
Another terribly ignorant statement!! If your statement is true then the designer of that circuit has failed miserably!
If the designer has designed the circuit correctly the CMR frequency range would be atleast upto the -3dB corner & even upto the unity gain frequency of the circuit.

One cheap, easy way to see if interconnects are your problem is to temporarily try the typical cheap ones that come w/VCRs, you know the type(i.e red/blue/yellow, 3 all together). Sonically they suck, but they are very well grounded! If RFI disappears with them, you'll know to upgrade to good grounded interconnects.

Search the archives for advice on grounding your system as a whole. Best solution is one ground from the rig to a copper rod buried outside. You can read for hours on best way to do this.

Power conditioners suck the life out of most amps. Avoid if possible.

The suggestion to rearrange gear 90 degrees, didn't mean to move it to a different wall. Just turn each component 90 degrees on its shelf and see if it makes a difference.

Another crazy thing to try is take aluminum foil and wrap it around where interconnects attach, particularly on preamp. Jud Barber of Joule Electra suggested this to me a long time ago when diagnosing an RFI issue. If it helps, try adding Cardas caps on your unused inputs and outputs. Cheers,

Spencer