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TRS Balanced and TRS Stereo Signal - Are They Wired The Same?

Discussion in 'Recording' started by aj113, Mar 31, 2011.

  1. aj113

    aj113 Active Member

    Hi all - I know the difference between a monaural TRS cable that is used for hum-cancelling balanced line, and a stereo TRS cable that carries two separate L and R signals - my question is, are the cables and connectors themselves one and the same thing?

    Both functions need cables that have ground wired to the sleeve and then the 2 'hot' wires connected to tip and ring respectively, so I don't see why one cable couldn't be used for the two different functions. (Not at the same time, obviously lol)

    The reason I am asking is because I need some TRS balanced patch cables but every web site I visit has them listed as 'stereo TRS cables' without any information about whether they can be used for balanced line patching too.

    Thank you in advance :)
     
  2. Big K

    Big K Well-Known Member

    There is nothing wrong to use the cables.

    Have a look here:

    sommer cable

    CORDIAL CFM 0,6 VV - Thomann UK Cyberstore
     
  3. aj113

    aj113 Active Member

    Sorry I don't understand your reply. The question is: can one cable be used to perform both functions?
     
  4. dvdhawk

    dvdhawk Well-Known Member

    Yes. TRS to TRS where it is wired Tip to Tip, Ring to Ring, Shield to Shield is exactly what you need for 1/4" balanced patch cables.

    Rarely do I see a stereo application where both ends are male.
     
  5. TheJackAttack

    TheJackAttack Distinguished Member

    More to the point, wire is just wire. It doesn't care what information you send down the little copper molecules. You just make sure that the connectors are wired the way you want them and go from there.

    I've posted this one quite a few times this last week but it's probably the best document on this subject.
    http://www.rane.com/pdf/ranenotes/Sound_System_Interconnection.pdf
     
  6. Boswell

    Boswell Moderator Distinguished Member

    A balanced mono TRS cable and an unbalanced stereo TRS cable are different, although you would have to tell them apart by visual inspection and not by using a multimeter. In a balanced mono cable, both signal conductors are carried within the same surrounding screen. In a stereo cable, the two signal conductors have their own screens in order to reduce capacitance and hence cross-coupling between the channels. The connector plugs are the same in both cases.

    For short distances (a metre or so), there is going to be little difference in performance between the two. For lengths of several metres, it pays to use the correct type. Most patch cables listed as "stereo TRS" are the two conductor in a single screen type, and so are suitable for balanced signal operation.

    Incidentally, the third common usage of TRS jack connections, an insert cable, is universally wired as two separate unbalanced coax cables, probably because it has to break out to two TS jacks or other mono connector.
     
  7. aj113

    aj113 Active Member

    Ahhh.... thank you Boswell. In the back of my mind I was sure that there must be some difference between the two. I had totally forgotten that stereo cables use separately shielded signal conductors. I suppose that could potentially 'unbalance' a balanced set up, because the two signal conductors in a balanced connection actually need to be twisted together so that they receive the same interference?
     
  8. MrEase

    MrEase Active Member

    Even more to the point, this is poor advice as wire is NOT just wire, as Boswell has already pointed out. Crosstalk, capacitance, inductance, loss and characteristic impedance can all enter the equation depending on the frequencies and length of the cable. Look more carefully at the Rane pdf and you will notice they are ALL balanced examples are as Boswell described. Not a "Stereo" cable in sight.
     
  9. TheJackAttack

    TheJackAttack Distinguished Member

    You are correct and I am properly scolded subtly by one and not so muc by another.

    The connections illustrated in the document are not stereo. However there are several instances of unbalanced connections and how to properly unbalance a balanced connector. And for analog connections and a short run here will be no issue using a mono cable for a "stereo" application. For digital applications, yes one wants the proper impedence etc. The OP wasn't concerned about digital. The OP was in fact looking for plane jane TRS cables.
     
  10. aj113

    aj113 Active Member

    The OP is looking for balanced patch cables that terminate in TRS connectors.
     
  11. TheJackAttack

    TheJackAttack Distinguished Member

    Yes. Normal TRS mono, not balanced stereo cables.
     
  12. aj113

    aj113 Active Member

    Just to clarify - I am asking whether normal balanced mono TRS is the same as a TRS cable that is wired for a stereo signal. I didn't mention balanced stereo - I'm not even sure there exists such a thing.
     
  13. TheJackAttack

    TheJackAttack Distinguished Member

    What most consumer shops call a 1/4" stereo cable for headphones etc is in fact not a stereo balanced cable. It only has three wires inside just like a pro audio TRS mono balanced cable only the two main wires (left and right +) have their own shield. If you were to cut one open and do an autopsy that is what you will find. These are generally cheaply made and use minimal strands of copper and cheap end connectors. So this is really as stereo unbalanced cable.

    A pro audio TRS balanced mono cable has three wires inside but there are more strands of copper per wire and usually far superior connectors on the ends. Also, both the main wires inside are wrapped in the same foil shield. Sometimes there is also whats called a drain wire but we'll leave that alone for the sake of simple explanation.

    For short runs these will do the identical job though again, the pro audio TRS mono cable (the standard) has generally better wire and connectors. A headphone cable will do in a pinch.
     
  14. aj113

    aj113 Active Member

    Thank you for your input, most of what you wrote has already been explained by Boswell, maybe you missed his post?

    However I am curious to know what you mean by 'stereo balanced cable'. As I said in my earlier post, I am not even sure if such a thing exists, - and to clarify once more, my opening post made no mention of this term. I was asking if a stereo cable and a mono balanced cable were one and the same thing. (And now thanks to Boswell I know they are not).
     
  15. TheJackAttack

    TheJackAttack Distinguished Member

    Boswell did correct my generalization from my first post. I should not have been so cavalier. Mea culpa. I come from a live audio background where people are too attached to the label and forget the function. And generally speaking again, you don't find headphone cables too much in pro audio unless you're seeking them out for replacement or extensions.

    Stereo "balanced" was another typo or misunderstanding of some previous post. Sometimes reading/replying on a phone gets me in trouble. It is possible to have a stereo balanced cable but it would not terminate in a TRS connector. Usually these are 5 pin XLR cables and are usually to be found with stereo microphones.
     
  16. MrEase

    MrEase Active Member

    My apologies for appearing too agressive - it certainly wasn't intended.

    Perhaps I could more gently point out that, again as Boswell stated, using a short length of "Stereo" cable would not be too harmful if used as a balanced lead (as there will still be an element of balance to any interference from external fields) but the corollary is not so true. If true balanced cable is used, even over just a metre or so, the capacitance of the two inner leads could cause significant crosstalk at high frequencies (where the audio is most directional) and thus reduce the stereo field. How much this would affect Stereo systems would depend very much on Input and Output impedances of the gear.
     
  17. TheJackAttack

    TheJackAttack Distinguished Member

    My apologies too. I was in the middle of tuning 11 pianos and was posting from the hip. Today, only two grands. A much better day.
     
  18. aj113

    aj113 Active Member

    OK guys well, Mr Ease, you make a good point. Although you may well be able to use a 'stereo' cable in a mono balanced scenario, the reverse may not be true. However, I am only concerned with buying balanced cables for my setup - (i never thought it would be so damned involved lol).

    So have a look at these guys, THE SSSNAKE SK369S-15 PATCHKABEL - Thomann UK Cyberstore what do you think? Incorrect product description, i.e. they are really mono balanced cables, or are they TRS jacks wired up with stereo signal cable?
     
  19. Boswell

    Boswell Moderator Distinguished Member

    Those are poor-quality balanced mono TRS cables. Use them at your own risk.
     
  20. TheJackAttack

    TheJackAttack Distinguished Member

    What country are you in or did I miss that somewhere?
     

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