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Nothing to do with XLR? I read that on post #2 of the thread!
Well, the problem on the 1124 is solved by using balanced XLR signals the whole way. The XLR connections aren't causing the issue, per se, it is Behringer's design (with grounded chassis) being incompatible with most/many/some (???) AVRs that output unbalanced via typical RCA.

It is an annoying issue, and I would be much happier if there was a solution that didn't involve either modified cabling to lift the signal ground or using a cheater plug to isolate the 1124's chassis.

Maybe I should toss this as a thought-experiment to one of my electrical engineers at work...

shinksma
 

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I had the hum issue. It was really annoying. With posts in this thread and help by Wayne I was able to make wire a cable. I am very grateful for the help I received on this and it worked out great. If you do decide to go with the 1124 I think you'll find the info in this thread helpful.
 

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Ok, I agree that it's not the 1124p's fault, exactly, since you're supposed to use it with balanced cables. But since I plan to do: receiver RCA sub out -> EQ -> EP2500 -> THT, then that could look like:

receiver RCA sub out -> XLR input on 1124p -> EP2000 using XLR -> THT
or
receiver RCA sub out -> miniDSP -> EP2000 (using RCA-to-XLR on input side) -> THT

I wonder if either is a safer way to go wrt hum. Note that I don<t have the EP2000 yet either.
 

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Just thought I'd mention that while trying to eliminate hum and you suspect the BFD even after using cheater plug or XLR ground lift trick, check your cables. A while back I did some cable "upgrades", replacing temporary cables (stereo coax cables from a cable-box) with what should have been equal-or-better quality cables from Monoprice. It seems they weren't even equal-quality. :( They introduced additional ground-loop-like 60Hz hum and lots of higher-order harmonic - picked up due to poor shielding around the connector ends, I suspect.

Swapped back to my temporary cables and the hum is diminished greatly (still there at low levels - now I need to figure out how to eliminate that completely or at least reduce it further). So I will experiment with other cables and configurations.

The hum I'm tackling is nowhere near as severe as the hum introduced natively by the BFD, so don't think I'm dealing with the end of the world. I would just like complete and utter silence when the audio signal is mute. :)

shinksma
 

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I returned my BFD in favor of a MiniDSP because I couldn't deal with the hum issue. I tried everything I could think of at the time with no results. I just had another thought has anyone ever tried grounding the BFD to their AVR phono ground (assuming they have one)? Could this work?
 

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I returned my BFD in favor of a MiniDSP because I couldn't deal with the hum issue. I tried everything I could think of at the time with no results. I just had another thought has anyone ever tried grounding the BFD to their AVR phono ground (assuming they have one)? Could this work?
Several pages back (and years ago) Wayne provided some very good information on how I could make an adapter. It worked great and totally solved my hum problem (which was significant).
 

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Several pages back (and years ago) Wayne provided some very good information on how I could make an adapter. It worked great and totally solved my hum problem (which was significant).

Is this what you did?





If so wouldn't this work: http://www.parts-express.com/pe/showdetl.cfm?Partnumber=240-430



3-pin XLR-F to RCA plug. Perfect for connecting a source with a balanced XLR output to a device with an unbalanced RCA input. Pins 1 and 3 are shorted with no connection to the shell. Note: This connector is not impedance matching.

.
 

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I did this several years ago (5?). I just pulled out my notes. I have that first figure you included, and scribbled on the page "center = pin 2" and "sleve = pin 3". I also updated the figure to show the black line connecting to pin 3 instead of pin 1, and I can't tell but it looks like I crossed off the connection of pin 1 (so maybe it is not connected - I can't recall). And underneath the drawing it says "This produces an unbalanced audio cable".

I'm not sure how to compare this to the plug you put in the post with the product. This would best be addressed by Wayne and perhaps others.
 

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I'm not sure thought that's the solution. As I noted, in my sketch for what I wound up doing I did not use that wiring (I think!). At any rate, did this work to take care of the hum?
 

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I bought all of that before I connected the BFD1124. Got it connected last night and no Hum issues. Could be that my grounds are all correct so don't know if my cable is helping...def not hurting anything. :D
 

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Now have hum issues..not only on the sub.

I've disconnected pretty much everything in my system and it's still there. I'm wondering if it's my power conditioner, Belkin PF60. I just installed that a few weeks ago and that's basically when the hum started in my rear surrounds. It has a ground point on it but I don't know where I would ground it to other than running a very long cable from it to the basement grounding point for my plumbing/ direcTv.

Could I run grounds from each of my devices in my system to the ground terminal on the PV60 so they're all terminated to the same point?

I'll go ahead and modify my rca to xlr cable like you did lovingdvd to see if that at least makes the sub no longer have the hum. It's slight but there.


I re-read your previous post and had a question. Which one did you end up doing below?


 

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I know this isn't an option for most, but I purchased a prepro with balanced outputs... Previously I had narrowed the ground loop down to my projector. The loop was going from the BFD, to the prepro via XLR-RCA, to the blueray player via coax digital, to the projector via HDMI. Insane... So first I replaced the coax digital with fiber, that worked but then I found I liked the sound of the analog outs on the Oppo better than my old HK doing the DA. So I put a cheater plug on the projector instead of the BFD. Ended up getting a new prepro and that changed it all. I guess my point is that you may be able to find a solution that doesn't involve the BFD if you try to track down the other "end" of the ground loop.
 

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Thanks for the suggestions but if I lift the ground on the XLR - RCA cable then I won't need a cheater plug. I just need to verify what picture above if the correct way to modify PIN 1.
 

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I'm having this problem now in my new home and just noticed it now that I'm getting around to setting the sub levels, etc. Is minimal if I keep the gain on the sub amp to 1/2 or less (which is where I've had it) but now I want to turn up the gain because I want to turn down the sub level at the receiver. I'm clipping the BFD input when I set the sub out level where I want it.

Anyway, I'm using 1/4" TRS to RCA cords from RadioShack. I decided to try what one poster on this thread had done and connect the ground screw on the bottom of the BFD to my HT receiver. I chose the ground on the AM antenna connections. This made a big difference in regard to the hum issue. It is not totally gone up has gained me some wiggle room in my sub gain setting. Bonus was that it cost nothing and is easy to do.
 

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Now have hum issues..not only on the sub.

I've disconnected pretty much everything in my system and it's still there. I'm wondering if it's my power conditioner, Belkin PF60. I just installed that a few weeks ago and that's basically when the hum started in my rear surrounds. It has a ground point on it but I don't know where I would ground it to other than running a very long cable from it to the basement grounding point for my plumbing/ direcTv.

Could I run grounds from each of my devices in my system to the ground terminal on the PV60 so they're all terminated to the same point?

I'll go ahead and modify my rca to xlr cable like you did lovingdvd to see if that at least makes the sub no longer have the hum. It's slight but there.


I re-read your previous post and had a question. Which one did you end up doing below?


In looking at the diagram I saved as a reference to what I had done, I have squiggly lines through the wire coming off of pin 1. I think that means I do not have it connected, but can't be sure. I also have written on the page "center pin 2, sleeve pin 3".

I really had no idea of what I was doing at the time and even less of an idea now. :) But I can say it solved my problem 100%. Please check with Wayne as he was my definitive resource and spoon fed me the solution so he probably knows off the top of his head what needs to be done.
 

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Hello fellow hummers--

I just got my first of 2 DIY subs up my stairs and all hooked up. HUMMM..... :unbelievable:

Onkyo-606 -> RCA -> RCA-to-1/4"-TRS -> BFD -> XLR -> EP4000 -> Sub

When I disconnect my cable coax from my DVR, or the HDMI cable from DVR to Onkyo, pretty much all hum goes away. Enough at least. I checked the earth ground of the dish coax. It appears to be well done and right next to my outside electrical mains, so there's nothing I can do to improve that.

Will this fix it? :dontknow:

http://www.mcmelectronics.com/product/33-8700&CAWELAID=220406689

* 5MHz ~ 2.4GHz bandwidth
* Compatible with antenna, cable television and satellite systems
* Reduces or eliminates the effects of ground loops
* Female "F" input and output connectors
* Insulated metal housing

I tried searching these 28 pages and other areas of the forum, but I couldn't find anyone that's tried this thing.

Thanks!
--Myles
 
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