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

Ty Ford November 23rd, 2007 11:15 PM


Originally Posted by Ben Moore (Post 780836)
The adapter cables I have right now are these:


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?

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


Hello Ben

The picture of the cable shows on a 1/4" TS and NOT a TRS, so I imagine it's NOT a balanced cable.

The MixPre is quite nice, but if you need mic level for you camcorder, make sure you order the adapter cables from Sound Devices that knock the line level outputs of the MixPre down to mic level.

My secret cable house is Gotham Audio in Nazareth PA. Contact Lewis Frisch there -- lewis@gothamaudiousa.com

Tell him I sent you for the NOS (new old stock) GAC-3. This is seriously good cable. I just ordered 2 50' and three 25' with XLR ends. Order the lengths you want and tell him what you want on each end. I guess that'd be a male XLR and a Male TRS.

You may want to get two 25" (1/4" TRS on one end, Male XLR on the other) -- and a regular 25' XLR female to XLR male instead of one 50'. If it'll will make your life easier coiling and uncoiling. Otherwise go for the 50'.

Great cables are a joy to work with. These are them. :)


Ty Ford

Gerry Gallegos November 23rd, 2007 11:33 PM

adapter cables
TRS is TRS, and its only MONO!! the reason people confuse this with stereo is because the TRS is the same connector as a "stereo" headphone connector, but they work in VERY different ways. the term balanced is because in a "Differential balanced circuit" meaning that pin 2 is the positive signal and pin 3 is the negative version of the signal (not ground, and out of phase with pin2) and a ground reference (shield). any noise incurred within the length of the cable will occur in both phases equally and when it gets "unbalanced" properly meaning the differential out of phase signal carried by pin 3 when it gets flipped in phase will make any noise out of phase with itself, there fore theoretically making it noise proof (or noise less), so if you have a long run you want to maintain a balanced link for the longest part of the run as possible. un-balanced signal has just a basic positive signal with a ground/shield. so for a long run its basically a BIG antennae, as well as having little or no noise rejection qualities. most SO (Soft jacketed) cable uses a spiral wound shield which has alot of gaps for noise to come in , where as "install type cable" has a foil shield but is not very flexible. in a balanced setup by design will reject noise even if the shield is missing. (which happens when you have to lift grounds) when there is a hum problem. when properly using a balanced structure I have been able to carry a "fairly" clean signal over 500 feet using cat 5 cable, something that would be absolutely impossible with an un-balanced cable. not to mention that a "line level" signal operates at +4 and an unbalanced signal operates at -10, thats alto of signal difference that can push throug a long cable run easier/better.

Steve House November 24th, 2007 03:08 AM

As you say, Gerry, TRS is TRS. But that's only a physical description of a 3 conductor connector. Whether it's mono or stereo is determined by what the 3 available conductors are being used for once they enter the two pieces of equipment the cable is patching together. I think a lot of the problem people have is because they focus their attention on the connector being used rather than the circuit it's functioning in. In fact a TRS connector can be used on a 3-conductor cable to carry either a single mono balanced circuit or a stereo pair of unbalanced circuits at your pleasure. For that matter, when used on an insert cable to patch an external processor into mixer bus, it normally carries an unbalanced mono output on the tip along with an unbalanced mono return INPUT on the ring with a common ground between them on the sleeve.

Steve House November 24th, 2007 03:15 AM


Originally Posted by Ben Moore (Post 780922)
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?


They're not labled because there is no difference - as I mention in my note above it's the same physical connector and probably the same cable. What matters is what is being fed out of the hole in the gear you're plugging it into. If it's the line out of a mixer, for example, you're probably dealing with a balanced, mono, signal. But if it's the headphone out, the cable is carrying a stereo pair of unbalanced signals.

I was just thinking as to the origins of our discussion being your client said you could connect to their board through a 1/4" jack. But you haven't mentioned exactly what mixer make and model they're using and which of its various outputs they might give you. If their board has a mono output jack that sends a mixdown of the left and right main channels for you to use that'll be one set of considerations but if their idea is to send you both channels by having you plug into an extra stereo monitor jack than that's a whole different set. Or are they thinking of giving you one or two of the mixer's AUX buses (if it has any)? And to make it more interesting, while most professional mixers do use 1/4 TRS jacks in a balanced mono configuration for most of their I/O, some exist (some of Behringer's entry level mixers for example) that use 1/4 TS unbalanced connections and you can't tell just by looking which it is unless they label it on the case (one 1/4 inch hole looks pretty much like every other 1/4 inch hole <grin>). See if you can find out exactly what mixer they're using and which of its outputs are going to be open to you so you can get hold of the manual (it's probably available online) to make sure just what you're dealing with - you can't always tell by looking and you shouldn't guess.

Ben Moore November 24th, 2007 10:31 AM

Thanks everybody for all the great information!

I now have a better understanding of what I'm working with here (and know what to look for on the board) I will make sure I know what kind of connection I'm plugging into.

Thanks again

Steve House November 24th, 2007 10:39 AM


Originally Posted by Ben Moore (Post 781117)
Thanks everybody for all the great information!

I now have a better understanding of what I'm working with here (and know what to look for on the board) I will make sure I know what kind of connection I'm plugging into.

Thanks again

Please, for your own peace of mind if nothing else, find out what board they have and read its manual if possible BEFORE arriving on-site for the shoot.

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