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Advice on RFI with a new integrated amp

I need some assistance on my Exposure 2010S. The only input I am using is the cd player, but with volume turned all the way down, I am picking up radio signals. If I turn the dial to the moving coil phono setting, even though nothing is attached to it, I can hear radio pretty loudly.

The corner of the house where our stereo is in under the outside wires, and it sits right next to the terminal for our Verizon Fios -- not the most ideal location, but it
is the only option.

Using the CD pots on the amplifier, you can only hear the radio pretty faintly, when the volume pot is turned all the way down. If I am playing cds, you can't hear anything, but since when I switch to the phono/aux1 setting, as I mentioned, I am picking up radio signals, and
the volume is louder. From what I read (and hear), it appears that the phono pot (perhaps in cahoots with the moving coil phono stage) is acting as a antenna, and picking up signals, which are cross-talking
across the other inputs on the amp.

How would you recommend addressing this? I am currently considering
shorting terminators on the phono, and other output pots and found some terminators online (audiophilia article).

At first I thought it might be my changing the speaker cables, from very thick cables to the slimmer DMNs, but that would not explain why the RFI is louder at the phono input than any of the others.

Whatcha think? Does this make sense?

The other option would be RCA caps.

Thanks,

Marty
martyw
jea48
2,944 posts
 

I am currently considering
shorting terminators on the phono, and other output pots and found some terminators online (audiophilia article).
Do not install shorting plugs on the outputs. Ok on the inputs....

At first I thought it might be my changing the speaker cables, from very thick cables to the slimmer DMNs, but that would not explain why the RFI is louder at the phono input than any of the others.
Does the radio station get louder if you increase the volume?

How long are the speaker cables?
If you still have the old speaker cables reconnect them and then listen for the radio station.
martyw OP
68 posts
 
Thanks Jea,

On point one, sorry -- I meant inputs.

On point two, yes, the volume increases if I turn up the volume, but again, it is most prevalent on the phono setting. On the other settings, it is there, but very much in the background.

On point three, the old cables are gone -- they were spades, and not compatible with the new amp, so I sold them.
Thanks again -- Marty
almarg's avatar
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almarg
8,673 posts
 
I agree that shorting plugs on all of the unused inputs (especially of course the phono input, but I'd suggest the others as well) should be step 1.

I doubt that the speaker cables have anything to do with it, in part because the very low output impedance of the amplifier would tend to "short out" any rfi/emi picked up there. And also because it would seem unlikely that anything picked up there would make it back to a circuit point near the input of the preamp section, where it could be amplified.

I'd suggest one other experiment that I'm curious about. Do you get the same radio signal pickup when NOTHING is connected to the inputs of the 2010S (meaning with the cdp disconnected)? (Obviously, turn power off while you are disconnecting the cable).

Regards,
-- Al
martyw OP
68 posts
 
Hi Al,

Thanks for the tips. I ordered the shorting plugs, and they should arrive later this week.

I do get radio when there is nothing connected to the inputs. I played around with putting a ferrite bead (from an old USB plug) by the phono input, but it made no difference.

When I am using the other pots, you can only hear the radio, when your ear is very close to the speaker, but it is pretty annoying nonetheless....

Thanks,

Marty
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