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  1. #1
    Junior Member
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    Output impedence of SB2

    I have not been able find this answer anywhere. Anybody here smart enough to figure it out?

    Carlton

  2. #2
    Founder, Slim Devices seanadams's Avatar
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    Quote Originally Posted by ribbonrail
    I have not been able find this answer anywhere. Anybody here smart enough to figure it out?

    Carlton
    It's 220 ohms - will drive any red/white RCA inputs. I'm puzzled as to why this question comes up so often. This is not like matching high power speaker loads or high-frequency digital connections.

  3. #3
    Junior Member
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    Thanks Sean

    It is probably not important to most. But if someone is using your unit to directly drive a low impedance amp it could come in to play if the players output impedence is to high. Others with more tech experience could better explain than me. You have a great product on your hands. Which IMHO believe is the future of high end audio


    Carlton

  4. #4
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    Carlton,

    220 ohms is a nominal value that will work fine. A value like that is required on many line output devices to decouple capacitive loads and prevent possible problems. A typical line-input resistance from a following device will be much much higher than 220 ohms.

    Even if the input impedance of the load was lowish the divider created would still result in a minimal db loss.

    The only question that might be of concern with the SB2 is with headphones hooked up. Some of those have rather low input impedances and might create a more appreciable drop. I'm not sure, but maybe there is a dedicated amplifier for headphones in the SB2.

    Cheers,

    Davey.

  5. #5
    Junior Member
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    Quote Originally Posted by Davey
    Carlton,

    220 ohms is a nominal value that will work fine. A value like that is required on many line output devices to decouple capacitive loads and prevent possible problems. A typical line-input resistance from a following device will be much much higher than 220 ohms.

    Even if the input impedance of the load was lowish the divider created would still result in a minimal db loss.

    The only question that might be of concern with the SB2 is with headphones hooked up. Some of those have rather low input impedances and might create a more appreciable drop. I'm not sure, but maybe there is a dedicated amplifier for headphones in the SB2.

    Cheers,

    Davey.
    Davey

    So does the output impedence change with the opamp bypass mod? Also if output level is cut in half with the removal of the opamp would it be safe to say it will generally play half as loud?
    Carlton

  6. #6
    Junior Member
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    Carlton,

    Yes, I would think so. However, you'd have to ask whoever's doing the bypassing how they have it configured.

    Most people perceive a 10db change as approximately half (or twice) as loud. Bypassing the output stage removes 4.8db of gain so this wouldn't be as much. But, there might be some other variables that come into play as well depending upon how it's bypassed. Once again, I think you'd have to ask the person doing the bypassing how they did it.

    Cheers,

    Davey.

  7. #7
    Junior Member
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    Davey
    As always thanks for you technical expertise. I will follow up with the modders.

    Carlton
    Quote Originally Posted by Davey
    Carlton,



    Yes, I would think so. However, you'd have to ask whoever's doing the bypassing how they have it configured.

    Most people perceive a 10db change as approximately half (or twice) as loud. Bypassing the output stage removes 4.8db of gain so this wouldn't be as much. But, there might be some other variables that come into play as well depending upon how it's bypassed. Once again, I think you'd have to ask the person doing the bypassing how they did it.

    Cheers,

    Davey.

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