The AI-1 Dreadnought Project Pt.1

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  • EndersShadow
    EndersShadow Posts: 17,531
    edited January 2012
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    Toolfan66 are those the Meniscus Audio spikes?
    "....not everything that can be counted counts, and not everything that counts can be counted." William Bruce Cameron, Informal Sociology: A Casual Introduction to Sociological Thinking (1963)
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  • Toolfan66
    Toolfan66 Posts: 16,906
    edited January 2012
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    EndersShadow wrote: »
    Toolfan66 are those the Meniscus Audio spikes?

    Yes!!
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  • headrott
    headrott Posts: 5,484
    edited January 2012
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    That case is very nice Larry! I like it! Prepunched holes for the Cardas binding posts, Meniscus spikes, and the transformer! Nice!

    Greg
    Relayer-Big-O-Poster.jpg
    Taken from a recent Audioholics reply regarding "Club Polk" and Polk speakers:
    "I'm yet to hear a Polk speaker that merits more than a sentence and 60 seconds discussion." :\
    My response is: If you need 60 seconds to respond in one sentence, you probably should't be evaluating Polk speakers.....

    "Green leaves reveal the heart spoken Khatru"- Jon Anderson

    "Have A Little Faith! And Everything You'll Face, Will Jump From Out Right On Into Place! Yeah! Take A Little Time! And Everything You'll Find, Will Move From Gloom Right On Into Shine!"- Arthur Lee
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  • Toolfan66
    Toolfan66 Posts: 16,906
    edited January 2012
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    headrott wrote: »
    That case is very nice Larry! I like it! Prepunched holes for the Cardas binding posts, Meniscus spikes, and the transformer! Nice!

    Greg


    Thanks Greg!!
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  • drumminman
    drumminman Posts: 3,396
    edited January 2012
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    Nice workmanship!

    What do you plan to do with the others you built? I'd love to buy one if you have any extras.
    "Science is suppose to explain observations not dismiss them as impossible" - Norm on AA; 2.3TL's w/sonicaps/mills/jantzen inductors, Gimpod's boards, Lg Solen SDA inductors, RD-0198's, MW's dynamatted, Armaflex speaker gaskets, H-nuts, brass spikes, Cardas CCGR BP's, upgraded IC Cable, Black Hole Damping Sheet strips, interior of cabinets sealed with Loctite Power Grab, AI-1 interface with 1000VA A-L transformer
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  • Toolfan66
    Toolfan66 Posts: 16,906
    edited January 2012
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    Headrott,Dumminman,Brgman,Polkmaster1 have first dibs on the 4 extra chassis I have. I will PM you guys Monday for details.
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  • PolkMaster1
    PolkMaster1 Posts: 847
    edited January 2012
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    If the Tool-Master made cases for a living, he would have many repeat customers from this forum.
    Statistics show that 98% of us will die at some point in our lifetime.

    The other 2% will work for WalMart.
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  • drumminman
    drumminman Posts: 3,396
    edited January 2012
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    Toolfan66 wrote: »
    Headrott,Dumminman,Brgman,Polkmaster1 have first dibs on the 4 extra chassis I have. I will PM you guys Monday for details.

    :cool: Thanks!
    "Science is suppose to explain observations not dismiss them as impossible" - Norm on AA; 2.3TL's w/sonicaps/mills/jantzen inductors, Gimpod's boards, Lg Solen SDA inductors, RD-0198's, MW's dynamatted, Armaflex speaker gaskets, H-nuts, brass spikes, Cardas CCGR BP's, upgraded IC Cable, Black Hole Damping Sheet strips, interior of cabinets sealed with Loctite Power Grab, AI-1 interface with 1000VA A-L transformer
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  • Toolfan66
    Toolfan66 Posts: 16,906
    edited January 2012
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    "OK" I just finished putting together one of the aluminum chassis, as stated above I built my first one out of steel and with the concern of the steel chassis changing the inductance of the transformer, and might have more floor noise I figured this would be a good time and get off my **** and get an aluminum one built with this thread coming back to life. Here in a few I will start doing some a/b testing of course only with my ears. Maybe sometime down the road DK can do some testing with the nice gear he has.:smile:

    I will update later today..
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  • Toolfan66
    Toolfan66 Posts: 16,906
    edited January 2012
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    Well just as I thought I hear no discernible difference between using a steel chassis or aluminum chassis but my curiosity can now rest on this matter.. I'm sure if it effects the sound it's very little that one can't hear it.. YMMV..

    For the record both cases are the same size 10 x 10 x 4 and 14ga.
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  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited January 2012
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    Toolfan66 wrote: »
    Maybe sometime down the road DK can do some testing with the nice gear he has.:smile:

    It's on my list of things to do.
    Toolfan66 wrote: »
    Well just as I thought I hear no discernible difference between using a steel chassis or aluminum chassis but my curiosity can now rest on this matter.. I'm sure if it effects the sound it's very little that one can't hear it.. YMMV..

    For the record both cases are the same size 10 x 10 x 4 and 14ga.

    This is good info. Most audio gear is housed in a steel case.

    Did you listen to a variety of music with both vocals and instrumental-only selections?
    Proud and loyal citizen of the Digital Domain and Solid State Country!
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  • Toolfan66
    Toolfan66 Posts: 16,906
    edited January 2012
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    DarqueKnight wrote: »

    Most audio gear is housed in a steel case.

    That was the reason I didn't think there would be any difference.

    [/QUOTE]

    Did you listen to a variety of music with both vocals and instrumental-only selections?[/QUOTE]


    Yes!!
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  • Toolfan66
    Toolfan66 Posts: 16,906
    edited January 2012
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    Sal,

    It won't matter if they are 5' or 13' cut it to your needs..
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  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited January 2012
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    I made my leads 10' on each side. Making them too short could limit your placement options if you need to move things around in the future.
    Proud and loyal citizen of the Digital Domain and Solid State Country!
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  • Toolfan66
    Toolfan66 Posts: 16,906
    edited January 2012
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    Right now I am using MIT shotgun3's for my Dreadnought..
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  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited January 2012
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    Making an AI-1 using the original pin/blade cable is doing things the hard way. Since both wires inside the original pin/blade cable are connected to the pin, you end up having to use an extra length of wire. I found it easier just to use a pair of speaker cables to begin with.

    See the attached instructions for guidelines on converting a pin/blade cable to an AI-1.
    Proud and loyal citizen of the Digital Domain and Solid State Country!
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  • PolkMaster1
    PolkMaster1 Posts: 847
    edited January 2012
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    Sal -

    Very nice work!!! I cancelled my order with Par-Metal and went with Tool For Lifes (TF66) AI-1. I hope to get it in time to have my AI-1 built over the weekend.
    Statistics show that 98% of us will die at some point in our lifetime.

    The other 2% will work for WalMart.
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  • Toolfan66
    Toolfan66 Posts: 16,906
    edited January 2012
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    Three chassis's ready to ship. I got the face plates back from the plater yesterday, I just opened up the holes from the powder coating and I chased all the threads with a tap to clear out the paint.

    These will ship out Monday, I have one on hold for a Polkie as he wants me to put it together for him. That leaves one left for anyone wanting to build a dreadnought I will not be doing any type of production run I only built these because I wanted a aluminum one.

    Cheers!!
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  • nspindel
    nspindel Posts: 5,343
    edited January 2012
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    Larry I'd be in for the last one, but can I see a pic first?
    Good music, a good source, and good power can make SDA's sing. Tubes make them dance.
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  • Toolfan66
    Toolfan66 Posts: 16,906
    edited January 2012
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    nspindel wrote: »
    Larry I'd be in for the last one, but can I see a pic first?


    Go to page 6 about half way down..
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  • huy
    huy Posts: 10
    edited January 2012
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    Dear Polk Experts,

    Could you help me to explain why AI-1 can help non common ground amp works with SDA speakers? What is the purpose of toroidal transformer in this case?

    Thank you very much.
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  • Schurkey
    Schurkey Posts: 2,100
    edited January 2012
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    huy wrote: »
    Dear Polk Experts,

    Could you help me to explain why AI-1 can help non common ground amp works with SDA speakers? What is the purpose of toroidal transformer in this case?

    Thank you very much.
    With a normal SDA, a bit of the "Left" channel electricity gets routed to the "Right" speaker, and returns to the amplifier through the right side wiring. Same on the other side--some of the Right side electricity gets routed to the left speaker, and returns to the amp through the left side wiring. If the amp is common ground, the stray bits of left and right electricity can find their way home using the chassis ground.

    If the amp is not common-ground, the stray bits of electricity stay lost and angry, and cause problems with the amp, the speakers, or both.

    Adding an isolation transformer (doesn't have to be toroidal) in the SDA cable assures that the left electricity never truly gets routed to the right speaker, and the right electricity never truly gets routed to the left speaker, all the electricity gets routed the correct channel of the amp, and therefore it doesn't need a common ground in the amp to find it's way home. No angry electricity, no problems for amp and speakers.

    The transformer can only be used on SDA speakers new enough to use a single conductor between left and right; older speakers used two conductors. The difference is usually (not always) apparent by the style of SDA cable connector, twin blades would NOT be compatible with the AI-1 transformer, a pin and a blade is.
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  • nspindel
    nspindel Posts: 5,343
    edited January 2012
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    Larry, can you do all the same drillouts as you? I've got some spikes that I'd use, and will use binding posts just like you.
    Good music, a good source, and good power can make SDA's sing. Tubes make them dance.
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  • Toolfan66
    Toolfan66 Posts: 16,906
    edited January 2012
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    They come with pre drilled holes just like the pics..
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  • nspindel
    nspindel Posts: 5,343
    edited January 2012
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    How much are they?
    Good music, a good source, and good power can make SDA's sing. Tubes make them dance.
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  • Toolfan66
    Toolfan66 Posts: 16,906
    edited January 2012
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    $70 Buckeros
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  • nspindel
    nspindel Posts: 5,343
    edited January 2012
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    I'm in, sir Larry. PM me payment details.
    Good music, a good source, and good power can make SDA's sing. Tubes make them dance.
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  • huy
    huy Posts: 10
    edited January 2012
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    Schurkey wrote: »
    With a normal SDA, a bit of the "Left" channel electricity gets routed to the "Right" speaker, and returns to the amplifier through the right side wiring. Same on the other side--some of the Right side electricity gets routed to the left speaker, and returns to the amp through the left side wiring. If the amp is common ground, the stray bits of left and right electricity can find their way home using the chassis ground.

    If the amp is not common-ground, the stray bits of electricity stay lost and angry, and cause problems with the amp, the speakers, or both.

    Adding an isolation transformer (doesn't have to be toroidal) in the SDA cable assures that the left electricity never truly gets routed to the right speaker, and the right electricity never truly gets routed to the left speaker, all the electricity gets routed the correct channel of the amp, and therefore it doesn't need a common ground in the amp to find it's way home. No angry electricity, no problems for amp and speakers.

    The transformer can only be used on SDA speakers new enough to use a single conductor between left and right; older speakers used two conductors. The difference is usually (not always) apparent by the style of SDA cable connector, twin blades would NOT be compatible with the AI-1 transformer, a pin and a blade is.

    Schurkey,

    Thank you. Could you list the minimum required specification of transformer?
    I have a SDA cable made by Ben, have only one conductor (pin). How this can be worked without negative terminal (blade)?
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  • FTGV
    FTGV Posts: 3,649
    edited January 2012
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    huy wrote: »
    Could you help me to explain why AI-1 can help non common ground amp works with SDA speakers?
    ....Nvm.Brain ****.

    Btw. those custom chassis would be excellent for a small DIY amp.
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  • Schurkey
    Schurkey Posts: 2,100
    edited January 2012
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    huy wrote: »
    Could you list the minimum required specification of transformer?
    The AI-1 as manufactured and sold by Polk had a tiny-**** transformer good for .13 amperes. The D-I-Y "Dreadnaught" project as spec'd by DarqueKnight has a transformer rated for nearly 7 amperes.

    Matthew Himself suggested a transformer having a minimum of 5 amps capacity. He lists several desirable electrical characteristics and they're in the first post of DarqueKnight's Dreadnaught thread. (THIS thread! Worth studying from the beginning...)
    A couple of years ago, Matthew Polk provided the following specifications for a toroidal transformer based AI-1:

    "1. DC Resistance of primary and secondary should be less than 0.8 ohms and preferably less than 0.5 ohms. The lower the better.

    2. Inductance of both primary and secondary should be at least 10mH. Ideal is around 14mH.

    3. Current capacity to saturation should be 5 Amps minimum.

    4. Of course the turns ratio is 1:1."


    So transformers from .13 amps and up can be suitable; but bigger is better. The usual transformer-of-choice has more than ten times the suggested inductance. Nobody seems to care about that, and everyone seems to think the big transformer sounds just fine.

    Many isolation transformers have a turns ratio of ALMOST 1:1; again this doesn't seem to get in the way of good sound. Theoretically, it would result in a slight bias to one channel. In practice--I guess it's just not that noticeable.
    huy wrote: »
    I have a SDA cable made by Ben, have only one conductor (pin). How this can be worked without negative terminal (blade)?
    Cut the cable somewhere in the middle, attach each end to the transformer windings. You'll need to connect the other end of the transformer winding to the speaker - terminal (or to the blade terminal of the interconnect connector) with an additional length of wire on each side.

    There's instructions for making an AI-1 hosted on this site. The transformer part numbers are long discontinued, but direct replacements are available--but if you're going to make the effort to do this, you'd want to use a larger transformer anyway.
    (Post #6 of the following thread:)

    http://www.polkaudio.com/forums/showthread.php?55888-POLK-AUDIO-Speaker-Wiring-Schematics-amp-More-Stereo-Dimensional-Array%28SDA%29
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