balanced audio outputs

Discussion in 'Archived Threads 2001-2004' started by BrianChim, Oct 27, 2002.

  1. BrianChim

    BrianChim Agent

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    Can someone explain the importance of balanced audio outputs in a prepro? I know Anthem and Sunfire and Aragon have them. I know Outlaw does not.
     
  2. David Judah

    David Judah Screenwriter

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    It can provide less noise and distortion provided it is implemented properly. Its possible to create a balanced output by using a phase splitter, which is cheaper, but does not pass along the advantages of a truly balanced output.

    I don't know for sure, but considering the price points of the pre/pros you mentioned, I would expect them to be truly balanced.

    DJ
     
  3. Wayne A. Pflughaupt

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    Balanced signals have increased noise rejection properties for long distance runs; they offer no real advantage for most home theater applications, where interconnecting cabling is typically short. However, they do afford the use of TRS or XLR connectors, either of which are far superior to RCA connectors.


    Regards,
    Wayne A. Pflughaupt
     
  4. Chas_T

    Chas_T Supporting Actor

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    Brian..

    I'll add to this thread a bit as someone on the forum made a nice description of the different types of balanced connections. I copied the post into a "Need to Know" folder on my desktop.

    Although it's a bit clear to me, if you have technical questions on this information, people such as Wayne and others who are more technically advanced then I, can probably answer your questions.

    I do use Cat Cable Silver balanced XLR connections on my Anthem. My only reason is because I figured there are so many connections and wires back there, that it seemed the correct way to make my connections to reduce noise and interference.

    Regards,
    Charles

    *************

    We need to make a distinction between True Balanced and Full Differential. Let's look at it in 3 stages:

    Fake "adapter" Balanced - the preamp/amp has an XLR input, but pin 3 is grounded. Electrically, this is nothing more than a convenience connection. Euh!

    True Balanced - What the AVM20 and MCA use: The XLR I/O have an op amp inverter to take advantage of common mode rejection. The negative phase is inverted and added to the positive phase (if it's an input), to cancel interference picked up by the cable.

    Both phases go through the op amp, not just the negative phase. Bottom line: If you want to reject noise pickup in long interconnects, then this is for you.

    Full Differential - What so many people seem to think they want when all they're really after is True Balanced connection.

    This is used in sensitive lab gear etc., and more expensive audio gear(including I believe some of Sonic Frontier's 2-channel tube stuff). It requires twice the circuitry, since each phase is amplified separately. What's the advantage?

    Rejection of interference generated under the hood. If an SE circuit with a real balanced input is laid out properly and the S/N ratio is already acceptable, there's no reason to pay through the nose for a full differential circuit, because you don't gain anything...or at very least you don't gain enough to come even close to justifying the enormous increase in cost. And if each side of the circuit is not absolutely matched, you will actually be worse off! This means even more cost...
     
  5. chung_sotheby

    chung_sotheby Supporting Actor

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    I might be wrong, and please correct me on this, but I think that the Anthem AVM-20 is not truly balanced, that the balanced outs are only there for convenience. I remember seeing a long and arduous thread on this subject some time ago, and I believe that the conclusion was that the Anthem was not fully internally balanced.
     
  6. Chas_T

    Chas_T Supporting Actor

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    HI Chung..

    I remember something like that too. Then someone with a bunch of technical expertise like yourself posted that it was in the True balance category. It may have been the poster where I copied the information that I posted above.

    Perhaps I'll put a mail out to Anthem and try to find this information out.
     
  7. Michael Mohrmann

    Michael Mohrmann Screenwriter

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    The AVM-20 has True Balanced outputs, according to Brian Florian's post here. They are not there just for convenience. There is a further step for balanced outputs, called Full Differential, that Brian also describes.
    Michael
    Edit: I just noticed that I provided a link to comments that Charles had pasted into his post above. Sorry about the redundancy.
     
  8. Chas_T

    Chas_T Supporting Actor

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    Awww. Brian F. is the gent who wrote that post.
    I am glad you gave credit to his work.
    Thanks Michael.
    As always.. Good info and for some reason, I thought you might read this post and clarify if the Anthem has true balanced inputs. [​IMG]
    Charles
     
  9. Michael Mohrmann

    Michael Mohrmann Screenwriter

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    Charles,
    "As always.. Good info and for some reason, I thought you might read this post and clarify if the Anthem has true balanced inputs."[​IMG]
    Some call it attention to details. Others call it being a pain in the a--. It's a fine line that I sometimes straddle, though I get the feeling I tend to lean to one side! [​IMG]
    I was curious myself some months ago about this very subject, and that's when I found Brian's explanation. It provides a nice counter to those who believe that the AVM-20's balanced outputs are merely for convenience.
    Michael
     

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