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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
 
Etbaby said:
"I suggest that you check that the outlet ground is connected and securely tightened. Also other devices connectd on that same electrical line can re-radiate EMI back into that outlet. See what else is on the same line and unplug each device one at a time to see if the problem goes away. Be very suspicious of computers."
Sounds like a very good idea. Another question: Have you checked to see if the problem occurs with the other outlets in that same room (if there are any others in that room)? If none of the other outlets cause the problem, then it's likely that particular outlet. If not, then it's likely that particular room and/or electrical line.*
*This is of such interest to me (in case you were starting to wonder....) because I'm in the middle of dealing with my OWN RFI/EMI problem, which may be solved, not sure yet.
vicks7 OP
182 posts
 
I have checked each and every outlet in this room and the same problem occurs. The problem also occurs in all the outlets in the room next door. I have tried unplugging all other devices, swapping interconnects and powerchords but to no avail. I am no expert on these things so what do I look for to determine if the outlet ground is connected?
mdhoover
695 posts
 
"I am no expert on these things so what do I look for to determine if the outlet ground is connected?"
Neither am I. (I THINK there's a copper wire in the middle of the thing that screws down.) Etbaby may know. I'll bet Albert Porter knows, too. I had an electrician install the Porter Ports for the dedicated circuit that we recently added. For me, one of the downsides of attempting something like that as a "do-it-yourself" project would have been the somewhat unpleasant prospect of getting electrocuted.....
-Bill
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.
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