Bridging Amps to run my SDA 1.2's

Audio D
Audio D Posts: 5
edited October 2007 in Vintage Speakers
I have a question for the forum members: I have 2 Adcom 555 amps I would like to use to drive my SDA 1.2's. I'm wondering if the amps will maintain common grounding when in bridged mode. Any guidance on this matter would be greatly appreciated.
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  • avguytx
    avguytx Posts: 1,628
    edited October 2007
    From what I understand...no they won't. You'll need the AI-1 Non Common Ground Interface cable to accomplish that. Maybe the Adcom amp owners will chime in soon.
    Richard? Who's your favorite Little Rascal? Alfalfa? Or is it........................Spanky?.................................Sinner.
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  • F1nut
    F1nut Posts: 50,734
    edited October 2007
    What he said, "no they won't."
    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."

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  • engtaz
    engtaz Posts: 7,664
    edited October 2007
    Trust me they will blow your drivers. Seen it done it. They could also blow your amps. I used 2- Adcom 555II and lost 8 drivers totals.



    engtaz
    engtaz

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  • heiney9
    heiney9 Posts: 25,204
    edited October 2007
    Audio D wrote: »
    I have a question for the forum members: I have 2 Adcom 555 amps I would like to use to drive my SDA 1.2's. I'm wondering if the amps will maintain common grounding when in bridged mode. Any guidance on this matter would be greatly appreciated.

    No they will not and you can't tie the neg. terminals together.

    Depending on the year or SDA's/type of IC cable you have it *might* be possible to build the AI-1 cable.
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • read-alot
    read-alot Posts: 812
    edited October 2007
    engtaz wrote: »
    Trust me they will blow your drivers. Seen it done it. They could also blow your amps. I used 2- Adcom 555II and lost 8 drivers totals.



    engtaz


    Too bad you didn't have a friend in Tampa who knows everything that could have saved you. :D
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  • Audio D
    Audio D Posts: 5
    edited October 2007
    Thanks for all the great input. I re-read my owners manual last night and it said you could put a ground between the chassis's of the two amps in lieu of the AI 1 common grounding module. Can anyone tell me if the common grounding module is available from Polk? I have never seen one come up on any auctions so I'm sure it must be quite difficult to come by.
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  • heiney9
    heiney9 Posts: 25,204
    edited October 2007
    Audio D wrote: »
    Thanks for all the great input. I re-read my owners manual last night and it said you could put a ground between the chassis's of the two amps in lieu of the AI 1 common grounding module. Can anyone tell me if the common grounding module is available from Polk? I have never seen one come up on any auctions so I'm sure it must be quite difficult to come by.


    Just for clarification you don't mean tying the neg terminals together on the 555's when each are run in mono? You CAN'T do that without blowing up the amplifiers.

    Your best option is to contact Ken at Polk, he can send you instructions for building an AI-1 cable. Which SDA SRS 1.2's do you have? I don't have the compendium handy here at work but I believe you need to have a pin/blade SDA type connector on the 1.2's to be able to utilize AI-1 cable.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • engtaz
    engtaz Posts: 7,664
    edited October 2007
    If you want I can send the email from Adcom tech support that said NO, under no circumstances do you tie the neg terminals together.

    Just don't do it. That is why I posted in your thread. My friend did it to his SRS 2's and he lost 4 to 6 drivers out of 8 total. Maybe you will only blow 14 drivers out of 16 and also blow the amp the amps.

    engtaz
    engtaz

    I love how music can brighten up a bad day.
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  • BrettT1
    BrettT1 Posts: 560
    edited October 2007
    Be very careful regarding bridging to mono. I constructed the homemade version incorrectly and blew an amp. I don't know if I just hooked it up incorrectly or what. Luckily the amp is all that toasted!!
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  • Audio D
    Audio D Posts: 5
    edited October 2007
    Does the same hold true for mono block amps, such as ADCOM 565's? I'm a bit confused as to what is meant by tie the negative terminals together. I also read this in the manual. For clarification, I own the 2.3 SRS's (I always get the 1.2's and 2.3's mixed up) and yes, it has the blade/needle terminal.

    I'm hoping to purchase the compodium as a reference source.
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  • engtaz
    engtaz Posts: 7,664
    edited October 2007
    Mono block amps are different then bridged amps. Always ask the manufacturer if you can tie the negatives together.

    engtaz
    engtaz

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  • Deadof_knight
    Deadof_knight Posts: 980
    edited October 2007
    Simply run them in stereo and bi-amp them then all is good and youll like the way it sounds !!!!
    :cool: " He who dies with the most equipment wins Right ? "

    Denon 3300 Adcom 535 BBe w/sub out 1 pr 4.6s 2 pr of 4 jrs Recent additions Samsung Lns-4095D LCD, Samsung hd-960 DVD, Monster HT-5000 Power center    ,HPSA-1000 18" sealed DiY home sub.:D
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  • engtaz
    engtaz Posts: 7,664
    edited October 2007
    :eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek::eek:
    engtaz

    I love how music can brighten up a bad day.
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