Topic: XLR to miniplug cable connections (balanced to unbalanced) question

[Microbe]

Hi,

I've been searching through the forum trying to figure this one out. If I'm making a connection from a Soundboard (balanced XLRs) output to a 1/8" stereo mini-jack (Iriver) will noise be introduced because I'm going from balanced to unbalanced without a transformer?  I realize the soundboard sticky gives options for cabling (I have those).  But I can't find much reference to the amount of noise introduced.  Is there anyone who can explain this to me...and if a transformer is needed any advice?

Thanks!

[stevetoney]

I'm a mechanical engineer, which means I have NO clue what the function of a transformer is (isn't that one of those toys that changes from a man into a mega monster?), but I had a cable made up for me that I use on the output of a MP-2 (which means it has two female XLRs).  The cables from those two females connect into a 1/8 inch male mini connector.  I've plugged it into a JB3 and the line-in of a 660 and it worked just dandy.  Maybe I wasn't searching for it, I sure didn't hear any extra noise.

[Microbe]

Hey,

thanks for the reply. At least you're one step up on me... you've used an XLR connection.  In this case the transformer would  help reduce ground hum.  I'm guessing it would properly ground the balanced output.  Here's a link to a product that does that:

http://www.sweetwater.com/store/detail/DTI/


Because the topic on connecting to soundboards only discusses XLR, 1/4" adapters and rca to 1/8" cabling, I'm not sure a transformer is necessary.  Which is why I'm completely lost  .

[Celac]

Hey,

thanks for the reply. At least you're one step up on me... you've used an XLR connection.  In this case the transformer would  help reduce ground hum.  I'm guessing it would properly ground the balanced output.  Here's a link to a product that does that:

http://www.sweetwater.com/store/detail/DTI/


Because the topic on connecting to soundboards only discusses XLR, 1/4" adapters and rca to 1/8" cabling, I'm not sure a transformer is necessary.  Which is why I'm completely lost  .

How about something like this: http://www.jensen-transformers.com/datashts/pc2xr.pdf ?  Which, in addition to using a transformer to unbalance the signal, also deals with impedance issues and the need to deal with the level difference between pro line outs and -10 line insputs.  The only downside I can see is that a box with Jensen xfrmrs will not be inexpensive.
Celac

[Nick's Picks]

you dont need a transformer.

just "unbalance" the cable. 
on the XLR end, pin 1 (ground) will be "jumped" to pin 3 (which is normaly OOP - signal).
the resulting miniplug end can be wired the exact same way, w/the shield grounded.  End result is an unbalanced mono 1/8th plug.

viola!
If you find noise on this, then wire the XLR end normally and then ground the mini plug.


Now, if you are making a stereo cable here.
then you ground at the XLRs as described, and then wire the 1/8th mini correctly w/the tip being left, the ring being right and the shield is grounded.

[Microbe]

Hey, thanks for the info.  I'll give it a try during sound check.  Worst case, I just use the RCA output from the board and try again some other time. thanks for the info Nick and everyone else!

[Nick's Picks]

if you have RCA output...then just use that. 
its unbalanced, and no different than what you will end up doing w/the XLR outputs any ways (unbalancing them for 3.5mm stereo)

[Microbe]

I normally would use the RCA', but the board only has an output level control on the XLR's... I have to attenuate from the RCA's.  I figured it would be "cleaner" not to attenuate.  Besides, it's good to experiment 

[Nick's Picks]

aaahhh...
well then, XLR and custom cable is the way to go.
good luck

[goodcooker]

http://www.sweetwater.com/store/detail/DTI/

The guy that I run FOH for gave me one of these when I was in his shop the other day. I used it to patch out of the (very hot levels) board into my iRiver and it worked fine. I have noticed that it introduces some hum to the chain if used to unbalance the signal.
It fuzzed out a little ( but the band was incredibly loud and the PA was humping just to keep up ) but whaddaya expect for fifty bucks.

[Evil Taper]

You can use any passive DI.  You could also just run XLR>XLR (mic cable) and then plug the XLR>3.5mm Y-cable right in front of your recorder to minimize any RF that might be introduced.  Shorter the run the better you are with unbalanced cables.