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  1. #1
    jjhavokk
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    Balanced/unbalanced

    Just a quick question. a standard guitar cable is usually unbalanced right? Balanced jacks have the extra dark line through the center don't they? I never really bothered with balanced/unbalanced cables in my small home studio, but now that I have added some equipment I have some interference problems and I decided I had better refresh a bit. I know all about what the difference is in theory, (i used to do live sound) I just need to remmember what some of the other implications are. There are other uses that don't necisarily relate to interference arn't there?

  2. #2
    Senior Member SC358's Avatar
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    Take a look at http://www.mediacollege.com/audio/co...onnectors.html.

    In either case balance to unbalance or unbalance to balance, the quality will suffer unless it's converted properly, that's the worse implication I can think of
    .
    SC358
    Relationships are based on compromises - behavior accepted is behavior repeated.

  3. #3
    yes, a standard guitar connector is 1/4" tr (unbalanced), which means you can only count 2 different connection surfaces on the connector: the tip and ring. The color of the ring that insulates the unbalanced is usualy black or red and on 1/4" trs (balanced or stereo depending on what type of equipment you are running) the colors are red and white for the insulators between the connection surfaces. Just remember, when you convert from 1/4" tr to XLR, the tip goes to pin 2 and the ring goes to pin 1 and then just leave pin 3 open, but if at all possible, just go to radio shack or some place that sells 1/4" tr to XLR converters becuase they actually take the 1/4" tip signal and flips the audio of it 180 degrees out of phase and sends it through pin 3 and send the normal unflipped phase audio to pin 2 and then makes your unbalanced audio now balanced, as well as they physically convert the connectors from 1/4" to XLR, YAY . To let all know, balanced is always better than unbalanced because balanced reduces the unwanted "noise" that is picked up in the cables and cancels it out leaving you with just the clean, desired audio. If you cant understand my explanation, a great page to go to is that link to that page on SC358's post, or if you would like to understand phase cancellation and how it works magic, just click on my "phase canellation" thread and though it's posts are long, it's worth it if you don't understand phase cacellation. I must apologise for my incredibly long post and I hope it helps. Good luck!

  4. #4

    Re: Balanced/unbalanced

    Actually, with much respect to you, andrewr, the converter you are refering to from Radio Shack, though it works very well, doesn't really make a balanced system out of an unbalanced one. It's wired like you say, but inverting the signal at this point only inverts the noise on the cable as well, hence no cancellation, which is the purpose of a balanced system to begin with I believe. It does, though, provide an impedence matching transformer I think, which is very important, especially when dealing with low signal levels. Check this out, though.

  5. #5
    DaleG
    Guest

    Re: Balanced/unbalanced

    jjhavokk - THE fundamental purpose of balanced signals is to eliminate noise from being induced into long runs of cable. If you interconnect balanced and unbalanced signals without using a matching transformer then you have essentially created an all unbalanced system that will be exposed to noise induction.

    You need a matching transfomer to covert between balanced and unbalanced. Note that davek100 is correct that if noise is already present in the unbalanced signal, then it will also be present when conveted to a balanced signal. However, the idea here is to convert between unbalanced and balanced right at the unbalanced jack to prevent noise from being induced.

    Example 1, let's say you need to connect a balanced mic to an unbalanced equipment input for whatever reason. Where should the transformer go? The answer is right at the unbalanced equipment input. That way the balanced signal from the mic is carried over the cable with noise rejection. The transformer plugged right into the unbalanced input eliminates any run of unbalanced cable and related noise induction.

    Example 2, let's say you need to connect an unbalanced bass amp line out to a balanced input on a mixer. Where should the transformer go? The answer is right at the unbalanced line output on the amp. The signal coming out of the amp shouldn't have any induced noise, and by coverting to balanced right there, once again the signal is carried over the balanced cable with noise rejection. The transformer plugged right into the unbalanced output eliminates any run of unbalanced cable and related noise induction.

    If you have computers, wireless devices or other poorly shielded/noisy equipment in your studio you will shurely have noise induced into unbalanced cables. So use balanced wherever possible.

  6. #6
    Bob
    Guest

    New accoustic-electric player

    I'm about to recieive my guitar after installation of the Taylor expression system, which has a balanced output. The straightforward connection is from the guitar to the balanced mixer input using a balanced cable. If I want to use and effect such as chorus, do I use transfrormers on both sides of the effect to maintain the balance. Will unbalanced cables be an issue if they are only ten feet long?

    Thanks for your help.

  7. #7
    Administrator Dave's Avatar
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    Hi Bob,

    If you want to maintain the balanced audio line, placing transformers immediately before and after the chorus will do it. If you can place the chorus right next to the mixer, you could use a short unbalanced cable from the chorus to the mixer and avoid the second transformer.

    If you wanted to, you might be able to use an auxiliary channel on the mixer for the chorus instead of placing it between the guitar and the mixer.

    Personally I don't think an unbalanced line would be a problem over 10 feet, especially in a controlled environment. It could be an issue in some live stage settings or if you've got a lot of other equipment running.
    Dave Owen
    MediaCollege.com

  8. #8
    Bob
    Guest
    Thanks for the advice.

  9. #9
    Bob
    Guest
    Another question.......What gizmo do I need? Is it something Musiciansfriend or similar site can provide?

  10. #10
    Administrator Dave's Avatar
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    A balanced transformer is what you are looking for. The following document looks like it would be worth a read:
    http://www.jensen-transformers.com/an/an003.pdf

    I would also check to see if your chorus will accept a balanced input. Some devices will take a balanced input via XLR or TRS (tip/ring/sleeve) connector. This would obviously be the best choice.

    It could be worth checking the cost-effectiveness of buying a transformer vs buying an effects unit which takes balanced inputs. To be honest I have no idea how the sums will work out but I'd be interested to hear from anyone who knows.
    Dave Owen
    MediaCollege.com

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