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SKZA
SKZA's picture
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Last seen: 8 months 1 week ago
Joined: Sep 1 2011 - 1:12pm
Serious RFI Interference

I just bought a used Exposure 2010s on eBay and I'm having some major RFI interference issues with it. I use it primarily with a Rega RP1 powered by a Musical Fidelity V-LPS that's hooked up to the Exposure with Audioquest Sidewinder interconnects. 

In between tracks and even during quieter parts of songs I can hear a local rap station coming through clearly. Needless to say it ruins the experience, but I'm really not sure where to start fixing it. 

The interference comes through no matter which input I choose and does not get louder or quieter when I change the volume. It also does not change significantly when I unplug the interconnects and have nothing plugged into the integrated, leading me to believe it's an issue with the Exposure.

Thoughts? Suggestions? I love the sound of my amp but this issue is a real killer. Thanks all. 

commsysman
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Last seen: 11 hours 42 min ago
Joined: Apr 4 2006 - 11:33am
RFI

One key thing here is that the interference does not change when you lower the volume control setting. 

This eliminates the sources, the cables, the preamp stages of the amplifier (pretty much), etc. Oh...wait a minute...this thing is a passive-input amplifier; no real preamp stage...hmmmm.

If the case is metal, the first thing I would try is running a separate ground wire from a screw on the case somewhere directly to a ground wire in a nearly electrical box. I am assuming that your electrical outlets ARE grounded (3-wire outlets). #16 or #18 wire is sufficient.

If that does not help, you could try connecting .01 microfarad capacitors rated at 600 volts across (in parallel with) each of the four main rectifier diodes in the main power supply. Sometimes the diodes act as a RF detector.

There are also points in the amplifier circuit path where I would try momentarily connecting a .001 microfarad capacitor grounded on one side by hooking the other side to a test probe and probing while the interference is there to see if it affects it, but this should be done only by a very knowledgeable technician.

Another thing you could try is connecting a .001 microfarad capacitor across the preamp out jacks, if it has them. You can do this by connecting the capacitor to a pair of RCA plugs and plugging them into the preamp out jacks.

Another thing to try is connecting a ,01 microfarad 600 volt capacitor to an AC plug (with proper care as to insulating all leads), and plug it into a spare AC socket on the same AC circuit the amplifier uses. This will kill it if the AC wiring in the house is acting as an antenna.

I had this same problem with a Harmon-Kardon tube preamp many years ago and solved it by putting .001 microfarad capacitors from cathode to ground on all six tubes.

 

SKZA wrote:

I just bought a used Exposure 2010s on eBay and I'm having some major RFI interference issues with it. I use it primarily with a Rega RP1 powered by a Musical Fidelity V-LPS that's hooked up to the Exposure with Audioquest Sidewinder interconnects. 

In between tracks and even during quieter parts of songs I can hear a local rap station coming through clearly. Needless to say it ruins the experience, but I'm really not sure where to start fixing it. 

The interference comes through no matter which input I choose and does not get louder or quieter when I change the volume. It also does not change significantly when I unplug the interconnects and have nothing plugged into the integrated, leading me to believe it's an issue with the Exposure.

Thoughts? Suggestions? I love the sound of my amp but this issue is a real killer. Thanks all. 

SKZA
SKZA's picture
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Last seen: 8 months 1 week ago
Joined: Sep 1 2011 - 1:12pm
Thanks for the advice,

Thanks for the advice, commsysman, but I think I've found a much easier solution: move the amp. I actually just moved it to the other side of my equipment cabinet, further away from my power cords and other cables, and the interference seems to be totally cleared up. I don't know if the interference had to do with the proximity to the cables or if somehow the interference was more in that spot, but it's crystal clear now.

I might still try your grounding idea, but I'm really glad I found another solution because honestly, you lost me 100% after that. I do appreciate the thoughtful advice though. Thanks. 

SKZA
SKZA's picture
Offline
Last seen: 8 months 1 week ago
Joined: Sep 1 2011 - 1:12pm
Thanks for the advice,

Thanks for the advice, commsysman, but I think I've found a much easier solution: move the amp. I actually just moved it to the other side of my equipment cabinet, further away from my power cords and other cables, and the interference seems to be totally cleared up. I don't know if the interference had to do with the proximity to the cables or if somehow the interference was more in that spot, but it's crystal clear now.

I might still try your grounding idea, but I'm really glad I found another solution because honestly, you lost me 100% after that. I do appreciate the thoughtful advice though. Thanks. 

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