common ground amplifier?

hifi junky
hifi junky Posts: 24
edited March 2014 in Speakers
Picked up a pair of SDA-2B's, great condition, and sounded GREAT!

Now that I have them home and am ready to connect, I am concerned that my power amp is not common ground.
It is my understanding that the SDA's require a common ground. My power amp is a Sansui B2102, late 80's.
I used the multi tester checking the continuity across both left and right speaker ground posts, there is slight movement on the multitesters meter, but not full.

Does anyone now if the Sansui B2102 is a common ground amp?

Thanks.
Post edited by hifi junky on
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  • hifi junky
    hifi junky Posts: 24
    edited March 2014
    To be more specific on my multitester readings, ohms set to x1k read 50% on the meter.
    Thanks again.
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  • FTGV
    FTGV Posts: 3,649
    edited March 2014
    I was able to dig up a schematic for that amp,it has a bridged output stage so is not common ground and cannot have it's negative terminals strapped.
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  • hifi junky
    hifi junky Posts: 24
    edited March 2014
    Would it be safe to say, that the power amp can be used as long as I don't use the interconnect cable?

    My Sony STR-DB940 AVR is 110 watts per channel, and does use a common ground. I may consider using it to power the SDA's instead of going through the receiver's pre amp. I just don't want to under power the speakers.

    Thanks for your help.
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  • F1nut
    F1nut Posts: 50,734
    edited March 2014
    Without the SDA cable you'll never get what the speakers are about and therefore it would be a complete waste. Your AVR will drive them, but nowhere close to what they are capable of sounding like.

    If they have the pin/blade cable you can use the AI-1 SDA cable or build a Dreadnaught. Both are isolation transfomers, which will permit the use of non-common ground amps.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • hifi junky
    hifi junky Posts: 24
    edited March 2014
    Can you explain the term dreadnought, and how I would do this.

    Thanks.
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  • hifi junky
    hifi junky Posts: 24
    edited March 2014
    I really want to take advantage of the SDA's capabilities. I may end up selling my current power amplifier and replacing it with a common ground one. Not sure if thins may be my easiest solution.
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  • zane77
    zane77 Posts: 1,696
    edited March 2014
    http://www.polkaudio.com/forums/showthread.php?74472-The-AI-1-Dreadnought-Project-Pt.1

    This will tell you all about a Dreadnaught
    Home Theater
    Onkyo PR-SC5508 Sharp LC-70LE847U
    Emotiva XPA-5 Emotiva XPA-2 Emotiva UPA-2
    Front RTi-A9 Wide RTi-A7 Center CSi-A6 Surround FXi-A6 Rear RTi-A3 Sub 2x PSW505
    Sony BDP-S790 Dishnetwork Hopper/Joey Logitech Harmony One Apple TV
    Two Channel
    Oppo 105D BAT VK-500 w/BatPack SDA SRS 2.3 Dreadnought Squeezebox Touch Apple TV
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  • PolkieMan
    PolkieMan Posts: 2,446
    edited March 2014
    This will answer most of your questions.

    Polk Sda Handbook
    http://vr3mods.com/uploads/SDA_Handbook_2011_Rev2.pdf
    POLK SDA 2.3 TLS BOUGHT NEW IN 1990, Gimpod/Sonic Caps/Mills RDO-198
    POLK CSI-A6 POLK MONITOR 70'S ONKYO TX NR-808 SONY CDP-333ES
    PIONEER PL-510A SONY BDP S5100
    POLK SDA 1C BOUGHT USED 2011,Gimpod/Sonic Caps/Mills RDO-194
    ONKYO HT RC-360 SONY BDP S590 TECHNICS SL BD-1
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  • hifi junky
    hifi junky Posts: 24
    edited March 2014
    Can the negative binding posts be strapped on the Sansui B2102 amp, would this work as a common ground?
    Just looking at all available options before deciding on replacing the amp.
    Thanks.
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  • FTGV
    FTGV Posts: 3,649
    edited March 2014
    As mentioned in post#3 no they cannot.
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