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-   -   XLR to 1/4 question (http://www.dvinfo.net/forum/all-things-audio/108574-xlr-1-4-question.html)

Ben Moore November 22nd, 2007 12:17 PM

XLR to 1/4 question
 
Can an XLR to 1/4 cable be balanced? Its seems non of the cables at B&H are labled as balanced unless they are XLR to XLR. If I'm getting a feed from a sound board and they only have 1/4 out avaliable, should I use an XLR to XLR balanced cable with a short 1 foot adapter cable? The run is about 50ft.

Thanks For your input
Ben

Steve House November 22nd, 2007 01:58 PM

Quote:

Originally Posted by Ben Moore (Post 780158)
Can an XLR to 1/4 cable be balanced? Its seems non of the cables at B&H are labled as balanced unless they are XLR to XLR. If I'm getting a feed from a sound board and they only have 1/4 out avaliable, should I use an XLR to XLR balanced cable with a short 1 foot adapter cable? The run is about 50ft.

Thanks For your input
Ben


Yes, if the 1/4 is a TRS (Tip, Ring, Sleeve) type. To be wired correctly, the Tip should connect to XLR-2, Ring to XLR-3, Sleeve to XLR-1 via the shield. Depending on the two pieces of gear being connected, sometimes you get better noise immunity by lifting the shield connection at the destination end and leaving it connected at the source end. Of course be very sure that at the board end it is being plugged into a balanced mono output and not a stereo unbalanced output which uses the same type of 1/4 TRS jack.

Sam Gates November 22nd, 2007 02:34 PM

If you can get the brand and model of the mixer you can probably find a manual online and determine if the output is balanced. Even if it is balanced it is most likely line level so a direct box to bring it to mic level may be a good ideaif you are going into a mic input.

Gerry Gallegos November 22nd, 2007 03:14 PM

XLR to 1/4
 
If the 1/4 inch is not a TRS (Tip, Ring and Sleeve), and you are unbalancing with an adapter cable you are unbalancing the entire run of the cable. Most XLR to 1/4 inch mono connectors are unbalanced by tying both pin1 and pin 3 together, there fore unbalancing the entire circuit. the best way to do this if the mixer puts out an unbalanced signal is by using a line matching transformer like the Little IMP from whirwind, or something similar with a transformer in it. that way you can remain balanced all the way to the transformer, and maintaining the noise rejecting qualities of a balanced signal.

http://www.zzounds.com/item--WHRLITTLEIMP

there are several other manufacturers that make these as well. but if your mixer has Balanced TRS output, then you're golden with a TRS to XLR cable, as long as you are going into a balanced "Line" level input of your device. If you need to go into a "Mic" level input then you need to use a Direct Box (commonly called a DI Box) and put this device nearest the mixer.

http://www.sweetwater.com/c957--Direct_Boxes

At 50 feet you want to remain balanced no matter what just for the noise rejection. so I would suggest to buy a 50 foot microphone cable, then use whatever will fit your situation at the other end (line matching transformer,DI box, XLR to TRS adapter). this way you end up with a 50' mic cable you can allways use then slowly build up your kit of adapters so you can plug into anything and remain balanced.

Ben Moore November 22nd, 2007 07:08 PM

Thanks for all the great input!

Here are a few more details. I'm using a VX-2100 with a beachtek adapter. So I can accept both line and mic inputs. So the best way to do this with the least noise added would be to make sure that i'm getting a balanced mono feed on both lines (left and right) and make sure that the adapter cable is TRS to keep it balanced for the whole run, does this sound correct?

Ty Ford November 22nd, 2007 08:15 PM

Depending on the input of your camera, you can ditch the beachtek and go right to the camera input, bypassing lots of extra circuitry.

I have a store bought rig I use to feed prosumer cameras from my mixer.
I have a pair of XLR female to male RCA cables. I have a combiner cable; two female RCAs to one 1/8" TRS.

Plug mics and mixers into the dynamic mics or my mixer outputs and 1/8" TRS into the camera.

Regards,

Ty Ford

Ben Moore November 22nd, 2007 08:23 PM

Thanks for the info Ty.
The only problem I see with that is the fact I have no level control with that set up. I dont control the sound board so I have to adjust for what is coming out of the board. The beacktek allows me to adjust the levels. I just want the best noise resistance leading up to the inputs on the beachtec. Any other input or suggesttions? (or anything I should watch for as far as noise being added to the signal)

Gerry Gallegos November 22nd, 2007 09:26 PM

adapter
 
If youre using the beachtek, keep on using it, it guarantees a transformer balanced signal from source to recorder. the problem with the RCA adapters is they "un-balance" the signal, just like the XLR to 1/4 mono cables do. and for 50 feet you want to stay balanced.

Ty Ford November 22nd, 2007 09:51 PM

Quote:

Originally Posted by Ben Moore (Post 780354)
Thanks for the info Ty.
The only problem I see with that is the fact I have no level control with that set up. I dont control the sound board so I have to adjust for what is coming out of the board. The beacktek allows me to adjust the levels. I just want the best noise resistance leading up to the inputs on the beachtec. Any other input or suggesttions? (or anything I should watch for as far as noise being added to the signal)

Hello Ben,

OK if it's someone else's mixer, that's different. I still wouldn't use a beachtek. A Sound Devices MixPre or 302. The limiters alone (and electronics) trump beachtek.


Wait a minute! With the right mixer, one with prefader sends, the person mixing can create a separate mix for you that does not change whe that person moves the faders.

I've done that before. You do have to have a helpful person on the board doing the mix and the board has to have enough sends and outputs. In some cases the board may be fully deployed and there just aren't anymore outs. You'll be good until the guitar player turns up his/her amp, which, if it's miced, will change your mix, but you'd hear that anyway.

Finally, if the mics are all dynamic (not condenser) you can get mic splitters. If this is not a big time gig, get the simple female XLR to two male XLR spliiter and take your own mixer.


Regards,

Ty Ford

Ben Moore November 23rd, 2007 05:31 PM

The adapter cables I have right now are these:

http://www.comprehensiveinc.com/prod...P%2DSPP%2D3EXF

I can't find any info about these being balanced or not, If I plug the 1/4 into the board and the other in to a 50 foot XLR cable and then terminate at the beachtek, am I going to be balanced for the full run?

Ty:
I added the MixPre to my wish list @ B&H, that is a sweat device, Limiters would be great to have.

Thanks
Ben

Bill Ravens November 23rd, 2007 05:53 PM

these are definitely NOT balanced.
the definition of a balanced cable is that the load and source connections are matched impedance. you can't get matched impedance if one of the 3 connector wires is unconnected.

sometimes, this is good, tho', because the 3 conductor balanced lines will, sometimes, set up a ground loop. the way to defeat a ground loop is to disconnect the ground shield at one end.

Ben Moore November 23rd, 2007 06:11 PM

hmmmm. That makes it tough then, should I stick with these or try and find some others that are balanced?. It seems like all the boards I plug into only have 1/4 out avaliable, other wise I would just stay XLR all the way.

Ben Moore November 23rd, 2007 06:15 PM

Also Comprehensive lables these as TRS, The above comments said that TRS would be balanced. So now I'm a little confused???

Bill Ravens November 23rd, 2007 06:50 PM

hmmm...If they're trs, then they ARE balanced. The photo looks like only 2 connector tip.

Ben Moore November 23rd, 2007 10:31 PM

So from what I read, there are "TRS stereo unbalanced plugs" and also "TRS mono balanced plugs". Not sure how to tell the difference as nobody seems to label them this way?. Any thoughts?

Thanks
Ben


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