Sda-2b

alexholeinone
alexholeinone Posts: 17
edited March 2013 in Vintage Speakers
Scored a pair of SDA-2B yesterday for $100.00, in great condition, but missing the IC. Is there a thread in how to make your own IC. ANd soomebody posted in here where just take a regular speaker about 10 Ft. in length and just push each end into the lower blade socket of each speaker. Has anybody done this??? Will it work and not damage the speakers. Help. Thanks
Post edited by alexholeinone on

Comments

  • bmbguy
    bmbguy Posts: 416
    edited March 2012
    Congrats. I'm sure you'll love 'em.

    What you need depends on whether it's a pin/blade or blade/blade config (I think 2Bs came in both). The experts here will take care of you with the details.
  • alexholeinone
    alexholeinone Posts: 17
    edited March 2012
    Thanks, so far so good. Can't wait to experience the SDA effect. I will post pic later.

    Still need help on DIY IC for them. Help anyone.
  • bmbguy
    bmbguy Posts: 416
    edited March 2012
    I'll give it a shot...

    First off, you need to know if your amp/receiver is common ground (a good percentage are) -- with power off, check between the L+R 'minus' speaker terminals with an ohmmeter to see if you've got zero ohms. If so, it's common ground. If it's NOT common ground, then the whole approach changes and you'll need to use an isolation transformer in your IC cable or you'll cause big trouble with your amp/receiver.

    Assuming a common ground: For a blade/blade config, I built a DIY cable for my SDA-2As, which are blade/blade (thin blade on top, wide blade on bottom). You can use plain speaker wire if you wish, and connect the thin blade on the left speaker to the thin blade on the right speaker with one conductor of the speaker wire. Connect the two wide blades together as well with the other conductor, and you're good to go! A 2-conductor "Jones" plug on each end works perfectly for the blade/blade setup.

    I'm not as familiar with the pin/blade setup (round hole and flat blade). Much of the discussion here that I have seen says you only need to connect the two round pins together (with something like the center pin of an RCA plug), and can skip the blade. You'll need confirmation on that if that's what your plugs look like.

    Hopefully I've got most of that right. I'm sure someone else will be willing to check my work.
  • alexholeinone
    alexholeinone Posts: 17
    edited March 2012
    It is a blade/blade config. My Amp is common ground. Where did you purchase the parts for the DIY IC. Your help is appreciated. And anyone else help, ditto.
  • TennMan
    TennMan Posts: 1,266
    edited March 2012
    It is a blade/blade config. My Amp is common ground. Where did you purchase the parts for the DIY IC. Your help is appreciated. And anyone else help, ditto.
    The blade/blade IC cable is available from Polk Audio for $40. Tell them you are a member here and you will get free shipping.
    • SDA 2BTL · Sonicaps · Mills resistors · RDO-198s · New gaskets · H-nuts · Erse inductors · BH5 · Dynamat
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  • bmbguy
    bmbguy Posts: 416
    edited March 2012
    I actually got my Jones plugs on eBay. But Google 'Jones plug' and you'll find them from many sources. Just make sure you get two-conductor plugs -- "Jones" plugs come in many, many configurations/pin counts.

    The guy I got my speakers from had made his own little 'blades' from the little spade-type connectors (just filed them down to fit, I think). I wasn't crazy about that -- they didn't fit that well, and that would allow the conductors to touch each other if they weren't inserted in the plugs. The Jones plugs make a nice connection, and keep the conductors separated.
  • F1nut
    F1nut Posts: 50,557
    edited March 2012
    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

  • littlewoodboats
    littlewoodboats Posts: 823
    edited March 2012
    Is the thin blade supposed to be on top for both cabinets? I checked mine and the thin blade is on top in the Right cabinet and on the bottom for the Left. Is something amiss? Everything seems to be working as it should.

    Sorry for the derail
  • alexholeinone
    alexholeinone Posts: 17
    edited March 2012
    The thin blades on mine are on the bottom. Thank you F1nut i will purchase the "Jones Plug" and use monster wire for the DIY.
  • Mardydom
    Mardydom Posts: 4
    edited March 2013
    bmbguy wrote: »
    I'll give it a shot...

    First off, you need to know if your amp/receiver is common ground (a good percentage are) -- with power off, check between the L+R 'minus' speaker terminals with an ohmmeter to see if you've got zero ohms. If so, it's common ground. If it's NOT common ground, then the whole approach changes and you'll need to use an isolation transformer in your IC cable or you'll cause big trouble with your amp/receiver.

    Assuming a common ground: For a blade/blade config, I built a DIY cable for my SDA-2As, which are blade/blade (thin blade on top, wide blade on bottom). You can use plain speaker wire if you wish, and connect the thin blade on the left speaker to the thin blade on the right speaker with one conductor of the speaker wire. Connect the two wide blades together as well with the other conductor, and you're good to go! A 2-conductor "Jones" plug on each end works perfectly for the blade/blade setup.

    I'm not as familiar with the pin/blade setup (round hole and flat blade). Much of the discussion here that I have seen says you only need to connect the two round pins together (with something like the center pin of an RCA plug), and can skip the blade. You'll need confirmation on that if that's what your plugs look like.

    Hopefully I've got most of that right. I'm sure someone else will be willing to check my work.



    Sir, thank you for your post. I was able to configure how to correctly connect my modified interconnect cable on
    my SDA CRS speakers. You're a big help.

    mardydom.
  • Schurkey
    Schurkey Posts: 2,101
    edited March 2013
    Is the thin blade supposed to be on top for both cabinets? I checked mine and the thin blade is on top in the Right cabinet and on the bottom for the Left. Is something amiss? Everything seems to be working as it should.

    Sorry for the derail
    My SDA 1Bs are just like yours--blade positions change depending on the cabinet. The sockets on these 1Bs are still stuck in place with the original glue, so that's how they were aligned by Polk.

    The 2B blade/blade is wired a little different inside the cabinet. With the SDA 2B blade/blade, you'll likely find that one blade socket in each speaker cabinet is connected to...nothing. If they were mine, I'd add about a foot of wire inside each cabinet from the currently un-used blade socket to the negative binding post. This will permit using the AI-1 isolation transformer via the blade/blade socket in the future, if you choose to. The 2B really only requires one conductor in the SDA cable, connected to whichever socket in each cabinet that were factory-wired--IF (big IF) you are NOT using the AI-1 isolation transformer.

    A cautionary after-thought: The SDA jacks on the cabinets are wired differently between SDA 2A and SDA 2B even when the 2B used the blade/blade socket. The same is true for the SDA 1B and the SDA 1C even when the 1C used the blade/blade socket. Be sure which series you have!!!