# My solution for the BFD hum/noise or "My custom $10.00 subwoofer cable."



## mississippi_xj (Jan 5, 2007)

Hey guys. I don't know if this has been conclusively discussed but I just made my own specialized preamp to BFD cable. I did this to get rid of the noise i was picking up in My bfd from using the rca -> ts (mono 1/4") converter plug.

I took some regular rg59 I had laying around and soldered an rca plug on one end. I then cleaned up that end with some heat shrink to make it look nice. On the other end I used a male TRS type plug (1/4" stereo) to plug into the BFD. I simply didn't hook up the "sleve" part of the plug. This is what they call "floating the ground" on the pro-audio sites when discussing eliminating hum. I then cleaned up that plug with some heat shrink.

This *COMPLETELY* took care of the awful ground noise I was having. I wasn't even able to knock it out with *3* filters on the BFD centered @ the noise. The filters helped a LOT but didn't completely knock it out. 

This did. I didn't have to buy a $100 unbalanced to balanced converter or anything. I ended up using ~ $10.00 in parts and am SUPER satisfied with the results.

The trick was taking advantage of the fact that the BFD didn't have to have a signal going to that "3rd pin" or sleve part of the balanced connection. This effectively lifted the "ground" for my audio connection and I didn't have to use a "cheater plug."

I thought I would share this. Hopefully someone will find it useful.


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## Wayne A. Pflughaupt (Apr 13, 2006)

Yup - that was covered in the BFD hum sticky thread as an excellent solution. Rane's Sound System Interconnection guide recommends the same connection for all unbalanced to balanced connections (#13, #14, #17, #18).










Regards,
Wayne


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## mississippi_xj (Jan 5, 2007)

Good deal... I have looked @ so much stuff in the past day or so on the interweb I wasn't sure if it had been covered here....

figured to err on the side of safety though!


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## floydo (Feb 10, 2008)

Wayne, for what its worth there is one subtle difference between the RG59 and #18 above. The RG59 is 2 conductor with the shield is used for the return in Mississippi's configuration, so in effect you have an unshielded cable. Still works very well, but in long parallel runs with other unshielded cables such as power etc you could inductively pick up noise hum. That said stereo/HT systems typical unbalanced configuration is subject to that, and the proaudio balanced systems appear to provide that shielding. So #18 is "the best way", but the $10 configuration is a great solution especially considering RG59 or 6 are so readily available.


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## mississippi_xj (Jan 5, 2007)

Exactly. I would have gone ahead and used the 2 conductor+shield cable if I didn't have the rg59 laying around. I was thinking last PM that this might be a good candidate for cat5 also (twisted pair and whatnot.)

I am just happy that the noise is gone!

cheers


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## mtbdudex (Jan 2, 2008)

Sorta related to this thread.

I'm setting up my IB sub next weekend (Beringer Eq and Amp) and want to buy Balanced XLR Female to XLR Male, this mic cable from Parts express seems to fit that.
Not sure if it's twisted cable or not.
(newbie Q time: :scratch::scratch: are all 3 pin XLR cables that use -,+, ground both ends "balanced"?)
http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=241-342&scqty=2










> The Dayton Professional XLR microphone cables are setting new standards of quality and value. These mic cables feature two 22 gauge copper conductors for maximum signal transfer, 95% coverage tinned copper braided shield, and a black PVC outer jacket that's durable and flexible. The precision-crafted black metal shell XLR connectors with gold plated contacts provide a solid, reliable connection, gig after gig. Lo-Z, XLR male to XLR female. Cable O.D.: 6 mm. Length: 3 ft.
> 
> Dayton Professional cables are designed to perform to the standards you would expect from a high-end cable, without making you spend a fortune on interconnect cables for your equipment. Dayton Professional...superb performance at a great price!
> 
> ...


I read the info in the link (thx for it by the way) http://www.rane.com/note110.html


> A balanced line requires three separate conductors, two of which are signal (+ and -) and one shield (see Figure 1a). The shield serves to guard the sensitive audio lines from interference. Only by using balanced line interconnects can you guarantee (yes, guarantee) hum-free results. Always use twisted pair cable. Chassis tying the shield at each end also guarantees the best possible protection from RFI [radio frequency interference] and other noises [neon signs, lighting dimmers].


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## brucek (Apr 11, 2006)

> are all 3 pin XLR cables that use -,+, ground both ends "balanced"?)


Yes, that is a balanced cable you are showing in your url.... it will work fine between the BFD and your amp (if it has XLR input). 

brucek


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## Wayne A. Pflughaupt (Apr 13, 2006)

mtbdudex said:


> I'm setting up my IB sub next weekend (Beringer Eq and Amp) and want to buy Balanced XLR Female to XLR Male, this mic cable from Parts express seems to fit that.
> Not sure if it's twisted cable or not.


I've dissected more dozens of mic cables than I care to remember, but I can't say I've ever seen one that _didn't_ have twisted conductors. Like brucek said, it'll work fine.  

Regards, 
Wayne


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## mtbdudex (Jan 2, 2008)

brucek said:


> Yes, that is a balanced cable you are showing in your url.... it will work fine between the BFD and your amp (if it has XLR input).
> 
> brucek


Thx, shortly my shopping cart at Parts express will go thru then!


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