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Post by howburger on May 19, 2006 0:06:45 GMT -7
I've lived with a hum/buzz in my IB for six months now and just today decided that I have to deal with it. It's much more pronounced now that I put a quiet fan in my EP2500. I've pinpointed the culprit but haven't solved it yet. It's the RCA cable running from my Rotel Processor to my BFD and on to the EP2500. I googled "hum and BFD" and came across this link: www.users.bigpond.com/bcolliso/earth-loop.htmI'm going to make a short cable to run between the BFD and EP2500 and snip the shield and see if that works. Maybe those of you with experience can save me some time and tell me that it won't work. I'll let you know how it goes. Harold |
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Post by chrisbee on May 19, 2006 1:29:18 GMT -7
Are you using jacks or XLRs?
I've used XLRs in stereo throughout and haven't a trace of hum.
The only non-XLR plugs are at my pre amp and power amp. But the other ends of these same cable are also stereo XLR equpped.
Cable prices were very modest at the music/pro-gear shops. I've used 3 metre (10ft) cables in places and they run right alongside the mixed power cables in a huge bundle.
I really must find (or make) some suitable conduit for them all. The white plastic channel stuff is fug-ly.
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Post by carpenter on May 19, 2006 1:51:14 GMT -7
fug-ly? Now there's a terrific word...  |
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Post by chrisbee on May 19, 2006 4:14:39 GMT -7
I'm sure St.Thomas wouldn't agree!  So it's lucky he's on his hols. ;D |
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jeffp
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Post by jeffp on May 19, 2006 5:07:40 GMT -7
I was thinking more along the lines of a ground loop problem. You can get a couple of cheater plugs to test that theory.
Jeff
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Post by ThomasW on May 19, 2006 7:16:17 GMT -7
Collo's site is a good one, we reference his studies on ported subwoofers on other forums.
There are multiple ways to deal with hum, sometimes a 'cheater' plug is the only thing that works and as noted they're a great diagnostic tool. Other times more 'proper' methods will solve the problem. Be careful of 'baluns', some filter out frequencies we want/need to keep.
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Post by howburger on May 19, 2006 14:39:53 GMT -7
So, are you saying to run a RCA to XLR from my Rotel processor to the BFD and then XLR to XLR from the BFD to the EP2500? If so, I can pick them up at the Guitar Center pretty close to my home. Thanx, Harold  |
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Post by howburger on May 19, 2006 14:48:57 GMT -7
Currently I'm running RCA to 1/4" jack from processor to BFD and 1/4" jack to RCA adaptor to RCA cable from BFD to another RCA to 1/4" jack adaptor and jack into EP2500. Just shows my inexperience at this.
Harold
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Post by ThomasW on May 19, 2006 15:15:13 GMT -7
Start with cheater plugs on both the BFD and amp.
If sources are on different circuits, then the ground loop potential is very high and cheaters maybe your only option.
What BruceK posted on the "Shack forum" about the Beringer's only being balanced isn't correct. They're single ended when 1/4th inch mono plugs are used. That's what you have now with your adapters.
I had a setup very similar to yours before adding in the Behringer crossover. Since it only has XLR's, I made up new cables for all the connections and things quieted a lot. But I continue to use cheaters since that lowers the noise floor even more.
There are people so phobic they think the use of cheaters is an automatic death sentence. That's bunk, they're only dangerous if the house wiring is faulty or if the piece of electronics is improperly made.
You can make up some good cheap custom XLR cables using the generic Dayton microphone wire from PE and your choice of XLR connectors.
I don't think RCA to XLR adapters work well. The only ones that do, are very $pendy, more expensive that making the custom cables.
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Post by howburger on May 19, 2006 16:13:08 GMT -7
Thanx Thomas. OK, so I will run XLR to XLR from BFD to EP2500. My only other option from processor to BFD remains RCA to XLR or 1/4". Does it matter which? Oh, and I've tried cheaters on either BFD or EP2500, but I don't think I tried them on both at the same time. I will try that. I'm also having two 20 amp circuits pulled to the room tomorrow on the same ground, so maybe that will help also. I will not give up! I will let you know when I hit pay dirt. Thanx again, Harold |
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Post by howburger on May 19, 2006 16:30:11 GMT -7
Thomas, I just went down and put cheaters on both the BFD and EP2500 and voila!  Sure glad you guys are there to lead me through these things. Now, one last item, need to build a hushbox for my SP4805 PJ. Thanx again for everything. Harold |
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jeffp
New Member
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Post by jeffp on May 20, 2006 19:28:55 GMT -7
Now if your having two 20amp pulls run make sure they are from the same phase of power and that should elminate your ground loop issue . I've been very lucky in that I have 3 dedicated 15amp breakers and no ground loop problems. More luck then skill as far as how it worked out.
Jeff
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Post by jman on May 21, 2006 12:18:22 GMT -7
Now if your having two 20amp pulls run make sure they are from the same phase of power and that should elminate your ground loop issue . I've been very lucky in that I have 3 dedicated 15amp breakers and no ground loop problems. More luck then skill as far as how it worked out. Jeff Would any decent electrician know about phase of power? My friend is going to run my new circuits and he is about 3/4 of the way through the apprentice program (6000 hours or so). |
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Post by Pete Mazz on May 21, 2006 12:44:03 GMT -7
Just tell him to install the new breakers on the same 110V leg inside the panel box.
Pete
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