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Worked! My hum is completely gone :T. Not a trace. And my satellite signal is fully intact. If removing your coax from your dish receiver gets rid of your hum, then this device should work for you. $30-shipped.

Isolation Transformer / Ground Loop Isolator
Distributed By MCM Part #: 4170
 

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I tried the MCM Ground Loop Isolator with Dish Network but without success. I was unable to get the signal to pass thru the Isolator to my Dish VIP722 receiver.

I ended up contacting Jensen Transformer and bought their Model SUB-RR. No more hum!
 

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A few have mentioned the behringer hd400 but there arent really any detailed specs available even the manual gives only the dimensions. Nothing mentioning its effectiveness at passing <20hz material signals, or better yet any negative effects on lower hz material like loss of volume..

Any input on this device?
 

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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.
I also used this method and the hum is just about gone. i will still look around for ways to eliminate it altogether but the wire from the bfd to my avr made a big difference in the hum. I can now turn my amp gain full on and lower the avr sub lvl so my bfd doesn't clip on lfe peaks.

Thanks HTS!!
 

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Hi guys,

I just bought a FBQ1000 (the 'new' DSP1124) and I have 2 different humming/distortion problems (at least I think it are 2 different problems)

problem 1:
As soon as I turn on the volume knob of my AVR I get a humming noise on my speakers. It is NOT there when I FULLY turn down the volume knob of my AVR but comes in as soon as I give 'one click' volume up on my AVR. The thing I should mention is that this problem is ONLY with my R, L and C channel. For these (R, L and C) channels I use a separate amplifier that is unbalanced (RCA) connected with the R, L and C rca pre-outs of my AVR. The hum is NOT present at my SR and SL channels (which are directly connected to the speaker outputs of my AVR). The hum from the R, L and C channels DOES NOT go away when I turn off the FBQ1000. The hum is the same, wether the fbq1000 is on of off. The hum only is not present when I unplug the cable going from my AVR sub pre-out to the FBQ1000 1/4 jack input.

problem 2:
The subwoofer is humming like hell with the FBQ1000 turned on. It is very noticable when scrolling and clicking with my mouse :scratch:

My setup:
Marantz SR5005: SR and SL are amplified directly by my SR5005 and my R, L and C channels are amplified by my NuForce MCH-2-C5
NuForce MCH-2-C5: connected with my Marantz SR5005 with unbalanced monster rca cables. Only R, L and C are amplified my my NuForce
Behringer FBQ1000: connected between AVR and subwoofer as follows: rca subwoofer pre-out avr => 1/4'' jack input 1 of fbq1000 with rca/jack plug => fbq1000 output 1 to rca input of subwoofer, also a rca/jack plug for fbq1000 output.


Could you guys tell me if they are both different problems and if I can eliminate one or maybe both of the problems with a cheater plug?
 

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If the noise started when you plugged in and connected the FBQ, then yes it’s all the same problem. As far as a solution, it’s impossible for us to troubleshoot long distance, so you'll need to wade through this thread and try some of the different remedies mentioned for yourself. But the first thing I’d try is a custom cable that lifts the ground connection at the BFD’s input and output, as noted in brucek’s post at the top of Page 5 of this thread. The same thing could be accomplished with an RCA to XLR cable that has the connection to Pin 1 (of the XLR) disconnected.

Regards,
Wayne
 

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Wayne,

thxz for your reply. Could the problem be the plug I am using?
http://www.bax-shop.nl/jack-rca/procab-vc104-rca-female-jack-male-adapter/product-details.html

Because on page 5 in this thread I see a different 1/4'' jack plug with TWO black rings instead of ONE on the adapter that I am using.

You are saying I could also use a adapter like this? http://www.bax-shop.nl/xlr-rca/neutrik-na2mpmf-adapter-xlr-male-rca-female/product-details.html#!prettyPhoto
But how do I disconnect the pin 1? I can t open the adapter can I?

Could I also try a custom made power cable with the ground not connected?
 

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If a device is designed to use a grounded a.c. outlet, it usually is not using a dual isolation power supply. If something opens up or shorts that makes the chassis hot, there is no place for the current to go so it looks for another path like through the body of a person touching the chassis or through the grounds on other equipments. If you had a hum, you had current flowing on the chassis ground to that ground on the a.c. line. That path is broken when you lift the ground, so now that current is looking for another path and cannot find one. If the current remains minimal, no problem. If it is high because of a defective device or something wired wrong somewhere in the system, it could be dangerous. If there are any protection devices internally that depend on that ground, such as MOVs, again, lifting the ground prevents this path.

Lifting grounds is just a patch on the problem. The problem should be corrected with a proper adapter or lifting a signal ground rather than lifting the a.c. ground.
 

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Will something like this work? A xlr ground lift adapter?
http://www.amazon.com/Hosa-GLT-255-Female-Ground-Stopper/dp/B000068O3M/ref=sr_1_1?ie=UTF8&qid=1353533701&sr=8-1&keywords=xlr+ground+lift

I had a hum and it disappears when I unplug the wire going from receiver to bfd. Currently I am using the cheater plug and it fixed the hum problem,however sometimes when I turn on the fan or light in that room I can here a little soft thump in the sub. If this xlr ground lift adapter works is it just doing the same thing the cheater plug is doing or is it a better fix? Would I need 2 of them to go from the bfd to the sub also or just one going from receiver to bfd?
 

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The noise you’re hearing comes from the light or fan being on the same electrical circuit as the sub (or possibly because they’re on the same phase), and it’s coming through the power line, not the signal chain. So I’ll be surprised if the XLR ground lift would work. Aside from that, the device you linked designed to work with a balanced signal chain. When you have an RCA to XLR connection, you have an unbalanced signal, so it would only be useful (if at all) if you have a balanced connection between the BFD and your subwoofer.

Regards,
Wayne
 

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If you’re asking about eliminating hum, any of the options found on this thread are better than the cheater plug, at least from the standpoint of safety. If you’re asking about the pop when lights are turned on, the cheater plug does nothing for that. The best way to solve that problem is to install a dedicated electrical circuit for your system, or lacking that plug all your gear into an existing circuit where there are no lights or fans.

Regards,
Wayne
 

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I tried removing all except the power cable but the hum/buzz still eminated from within my FBQ 1000 not the speakers. I've tried placing the power cable directly into the socket and also tried two other sockets (230V).

I find it a little strange that the hum fix should be placed in the audio path as the hum seem to be an electrical problem. Can anyone explain this to me?
 

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My simple solution - connected a small wire from the ground terminal on the back of my receiver (Denon 4311) to the outside metal part of the RCA plug connecting the receiver subwoofer output to the BFD TRS input.
 

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I have tried many things to get rid of the hum. I have the Lexicon MC12HD sub-woofer output connected to the BFD DSP1124P input. The output of the BFD is connected to a JBL 6290 power amp for the sub-woofer. The original configuration had all balanced cabling and I got a hum. I turned off everything except the BFD and the power amp with no improvement. I have done the following:
changed the connectors to the BFD to unbalanced -- no change
put a ground lifter connecter between the BFD and the amp -- no change
tried a cheater plug on the BFD -- no change

What should be the next attempt?
Any help will be greatly appreciated.
 
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