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Eliminating RFI

Dear All
I am experiencing problems for the first time with RFI through my Singlepower headphone tube amp. I have concluded that it is due to an unclean power supply as I do not pick up this interference using a wall plug in another room in the apartment and as I have also swapped out power cables and interconnects in the room to no effect. Most of my equipment is UK 240 volts and I run the mains (Brazil 110 volts) through the transformer to the equipment - however, I have never experienced any problems with this equipment - but as the headphone amp is 110 volts I am running it directly through the Brazilian mains (without the transformer) and I am now having problems.
Does anyone have any suggestions for me to eliminate this interference? I need to keep all my gear in this room so moving it all to another room is not an option unfortunately.
Many thanks
James
vicks7
mdhoover
695 posts
 
Vicks7,
Have you made any progress with your RFI problem?*
*My own RFI problem has been largely ameliorated, but not entirely solved. This is an extremely difficult problem given that RFI can be airborne or carried through the lines, or sometimes generated by the equipment itself. Another dilemma is that dampening materials can sometimes cause dynamic range constriction. Also, trying to find a single, coherent source of information on this topic has been difficult for me. So it would improve my morale to know that someone else (i.e., you) has been able to defeat or at least largely tame this beast.
vicks7 OP
182 posts
 
Unfortunately not, although I am starting to think it is also airborne. When I was adjustimg my speaker cable by taping it to the floor (to stop it hanging in the air) the RFI seemed to reduce in strength. So, with a CD, Amp and Speakers I get the RFI through the speakers and if I plug a headphone amp straight into the mains with nothing else other than a headphone cable I still get RFI. Very frustrating. I am auditioning some Audiopax gear at the weekend and I have asked the dealer to bring some power conditioners as well to see if this helps.
mdhoover
695 posts
 
Another idea that may or may not help: Ferrite cylinders that clip around your cables. Don't know for sure how much dynamic damping they cause. A pricey alternative to consider would be Z Sleeves by Z Cable. Here's a link to those:
Z Sleeves by Z Cable
I've never used them, only heard of them. Good luck and don't give up yet.
-Bill
tubeears
136 posts
 
A small "Faraday cage" may work. A Brass or copper screen box that would cover the encloser of your headphone amp. Thinking about it for a moment, I have seen various "metal" mesh containers and other "mesh" office supplies at Office Depot and even Wal-Mart. They are painted, so I don't know the metalurgy. I am certain that the stores would think not highly of anyone scraping the paint off of them before purchase, but they seem cheap enough. For a few bucks it might be worth a try.

Tubby
sbank's avatar
sbank
3,379 posts
 
If you can find shorting plugs, try them in any unused inputs on your preamp. They are helping me w/similar issue. Cheers,
Spencer
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