SDA Effect

Cthulhu11
Cthulhu11 Posts: 69
edited May 2010 in Vintage Speakers
OK recently posted about wife letting me get new amp blah blah blah. What i would like to know is about the 1 ground on the amplifiers for sda to work. Im look at a krell ksa-150 amp. But it's 2 monoblocks. i dont know much about this amp and dont even know if it does have 1 ground on it, And i think someone posted on this topic awhile back but i can't seem to find it. Why again does the amp need 1 ground for sda to work
Post edited by Cthulhu11 on
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  • Bobsama
    Bobsama Posts: 526
    edited May 2010
    Because it creates a ground loops. If you have an SDA-1C loudspeaker, you can use the modified AI-1 cable which lets you use those loudspeakers with non-common ground amps.

    commongrounddiagram.png

    That diagram is true at least for my Transitional SDA-1's. From what I understand, at least in the RTA-style and Blade/Blade SDA models, the amp needs to be common ground so the dimensional loudspeakers are grounded properly. Non-common-ground will have heat buildup and won't be properly regulated, or somehting like that. Either way, the SDA cable carries active signal from loudspeaker to loudspeaker.
    polkaudio Monitor 5 Series II
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    TEAC AG-H300 MK III stereo receiver
    beyerdynamic DT-880 Premium (600 Ω) headphones
    SENNHEISER HD-555 headphones
    Little Dot MK IV tube headphone amp
    Little Dot DAC_I balanced D/A converter
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  • Cthulhu11
    Cthulhu11 Posts: 69
    edited May 2010
    mine are SDA 1c w/pin/blade interconnect cable
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  • Bobsama
    Bobsama Posts: 526
    edited May 2010
    Oh. Then you can build the AI-1 interconnect cable and use them with non-common ground amps.
    Here are the plans for the AI-1 interconnect cable.
    http://www.polkaudio.com/forums/showpost.php?p=677960&postcount=6
    polkaudio Monitor 5 Series II
    polkaudio SDA-1 (with the SL1000)
    TEAC AG-H300 MK III stereo receiver
    beyerdynamic DT-880 Premium (600 Ω) headphones
    SENNHEISER HD-555 headphones
    Little Dot MK IV tube headphone amp
    Little Dot DAC_I balanced D/A converter
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  • billbillw
    billbillw Posts: 6,865
    edited May 2010
    If you are still shopping, just find a nice common ground amp. There are plenty of them.
    For rig details, see my profile. Nothing here anymore...
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  • Cthulhu11
    Cthulhu11 Posts: 69
    edited May 2010
    i am in the market and have not purchased one, but thats good info to know for future thank you gentlemen
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  • F1nut
    F1nut Posts: 50,755
    edited May 2010
    What i would like to know is about the 1 ground on the amplifiers for sda to work. Im look at a krell ksa-150 amp. But it's 2 monoblocks. i dont know much about this amp and dont even know if it does have 1 ground on it,

    What do you mean, 1 ground?

    The matter concerns common ground amps verses non-common ground amps, which includes dual mono and mono blocks. Common ground amps share a ground between the 2 channels, which can be tested by measuring ohms at the negative outputs.

    In addition, not all 1C's can use the AI-1.
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  • ESavinon
    ESavinon Posts: 3,066
    edited May 2010
    The Krell KSA-150 is a stereo amplifier not a monoblock amp. It's compatible with the sda series.
    SRT For Life; SDA Forever!

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    Four main satellite speakers, six powered subs, two dedicated for LFE channel, two center speakers for over/under screen placement and three Control Centers. Amaze your friends, terrorize your neighbors, seize the audio bragging rights for your state. Go ahead, buy it; you only go around once.
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  • BuckeyeTim
    BuckeyeTim Posts: 483
    edited May 2010
    ESavinon wrote: »
    The Krell KSA-150 is a stereo amplifier not a monoblock amp. It's compatible with the sda series.

    Ditto

    But if you do end up with some kind of mono-block setup it is usually not that big of a deal. For my Adcoms, all I had to do was connect the negative binding posts together (per Adcom email). I did make another jumper to connect the two chassis together just for good measure though. It is easy enough to email or call support for the amp/amps you wish to buy and get their reccomendation.
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  • cnh
    cnh Posts: 13,284
    edited May 2010
    +1, BuckeyeTim...some prodigious power there with two GFA-565s! Very nice....I bet your SDA-1Cs love you for it!

    cnh
    Currently orbiting Bowie's Blackstar.!

    Polk Lsi-7s, Def Tech 8" sub, HK 3490, HK HD 990 (CDP/DAC), AKG Q701s
    [sig. changed on a monthly basis as I rotate in and out of my stash]
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