SuBXeRo Posted February 11, 2011 Share Posted February 11, 2011 ok, so i have had a couple threads about my ground loop issues and have really troubleshot it to hell today. I left everything connected as is (like my cable box, dvd player, etc etc) and well, my findings from my testing were rather, well, unexpected. 1. I took a different shielded RCA cord than what my 5 channels have used. 2. I muted my UMC-1 as this ground loop shows itself with or without the umc-1 muted. 3. I took that 1 rca cord and connected to each of the left channel on my umc-1. I then changed the rca location to each of the 5 channels on my xpa-5 and moved 1 speaker at a time along with the RCA cord. I got silence each time, and when unmuted sound fine, no distortions. 4. I proceeded to troubleshoot using step 3 for each of the right, center, rear right and rear left channels. I have achieved the same resultson each channel in each configuration, perfectly quiet. 5. I proceeded to use another shielded RCA cable tested it alone, achieved the same results as before, the cord works and no distrotions. 6. I hooked up 2 random channels, 2 speakers, 2 rca cords. I got extremely bad hum. I tried different channels, still, very bad hum. Much louder than what i had previously. Any ideas? Why would my hum be louder than before? Wierd i say, very wierd! Quote Link to comment Share on other sites More sharing options...
Rivernuggets Posted February 11, 2011 Share Posted February 11, 2011 Have you tried that same systematic musical RCAs with components (cable box, dvd....) removed? For me the cable box was the culprit. Not a problem now as I don't have cable anymore. Just an inside antenna. After installing this into the cable line from outside (thanks cfelliot!), the hum was reduced considerably. I still have some surfacce noise noticable if I'm a couple feet from my RF-7s. It must be the dimmer switch in the dining room. Looking into having an electrician come out and run a dedicated 20 amp outlet. Quote Link to comment Share on other sites More sharing options...
Stolenrs Posted February 11, 2011 Share Posted February 11, 2011 Any ideas? Why would my hum be louder than before? Wierd i say, very wierd! not real sure why it would be louder [^o)], but here is what happened to me. I had the same issue with a hum that was driving me crazy, I upgraded to a onkyo tx-sr705 for the HDMI switching, upon swapping it with my integra, I powered everything up and wham there it was. I spent weeks trying to figure out where it was comming from. I did the same sort of tests unhooking and swapping cables, I even swapped my integra back and it had aquired the hum. Well after several fustrated weeks I realized that I had looked at every cable except my sub cable. I had a 30' cable to go through the walls and such, I ran down to BB and bought a new cable tried the new one and wolla no hum. I never thought of looking at it before, might want to try that cable if you haven't already. Not really lookin forward to replacing the cable in the wall though!! Hear your pain though..... [:@] good luck ~ross Quote Link to comment Share on other sites More sharing options...
SuBXeRo Posted February 12, 2011 Author Share Posted February 12, 2011 would rca ground loop isolators work you think? will it degrade the signal quality at all? i used them in my car from my headunit and it solved my issues. Quote Link to comment Share on other sites More sharing options...
Fish Posted February 12, 2011 Share Posted February 12, 2011 I'm not sure how far you've been through testing but generally you unhook everything.Once unhooked you connect speakers, amp, etc until you get hum.Sorry if you've already done that. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted February 12, 2011 Share Posted February 12, 2011 would rca ground loop isolators work you think? will it degrade the signal quality at all? i used them in my car from my headunit and it solved my issues. it depends how they are made, some use transformers, some just use coupling capacitors, some use both. since ground loops, once identified, are easy to resolve, I would continue the identification and discovery process. I once had a situation where there was a hum that was caused by a component attached to my amp, even if the component was not used, even if the component was off. Some how everything was looping thru it. I solve the issue by replacing the power cord with a power cord from one of the south american. countries. the cord was basically a 3 prong female which connected to the component but a two prong male which plugged into the wall. Basically a fancy cheater plug. If I had to do it today, I would use the double series opposing diode approach for the ground in a fancy metal out let box. Quote Link to comment Share on other sites More sharing options...
SuBXeRo Posted February 12, 2011 Author Share Posted February 12, 2011 i hink i may have isolated the problem. Channel 4 (looking at the amp from the front, numbered left to right) produces the most distortion (hum noise) of all of the channels. It seems that some channels are noiser than other, why, i dont know, possibly that one bum channel is screwing up the others? I also disconnected everything from the processor and tested this all out too, also trying different outlets and the same results have appeared. Quote Link to comment Share on other sites More sharing options...
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