2BTL question...

This is a safety question... I just picked up a nice pair of 2B's and want to TL them. They are B/B from 1987 and the large blade has no wire. Do I need to modify this or is it just upgrade the crossovers and drop in the 198's and I'm good? Looking at the schematic, it doesn't look like there are any additional wires run, but I thought all B/B had current running through both blades?

Answers

  • pitdogg2pitdogg2 Posts: 14,623
    edited September 29
    Transitional set not uncommon, but i thought that one blade had wire going to negative binding post.
    Pin/blade connection only the pin carried signal the blade was more for support unless you used the AI-1 cable for non common ground amps then the blade was used as ground as inside the blade went to negative binding post to connect the grounds to the amp.
  • I've tried to find out through the forums but can't seem to find anything definitive about this. I'm hoping some of the resident experts can chime in on this :smile:
  • pitdogg2pitdogg2 Posts: 14,623
    yours are two board model correct?
  • No, they are single 3rd gen.
  • pitdogg2pitdogg2 Posts: 14,623
    MrNaturl wrote: »
    No, they are single 3rd gen.

    some of the early models using the B/b interconnect socket did in fact have dual boards. That is why I asked. I would think that it should still of had the wire from one blade to negative binding post if it was single board. Some early SDA1C's were incompatible with anything non common ground later versions were if used with the AI-1 cable instead of the normal Pin/Blade cable.
  • You want to jumper the wide blade to the negative binding post.
    2 channel: Anthem 225 Integrated amp; Parasound Ztuner; TechnicsTT SL1350; Vincent PHO-8 phono pre; Marantz CD6005 spinner; Polk SDA2BTL's; Cables ZU Mission IC's, SC and power cords, all into a PS Audio Dectet Power center.

    All TV's sound enhanced by Polk Magnfi Mini's.

    Other; S60'S, M10 series II, M7C's, Hafler XL600 amp, RB-980BX, Parasound HCA-1500 amp , P5 preamp, all in storage. All speakers have had crossover rebuilds, resulting in a small fortune invested in Sonicaps, and tweeter upgrades.

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  • You want to jumper the wide blade to the negative binding post.

    Ok that's what I was wondering. Isn't that how the p/b is set up inside the cabinet?
  • pitdogg2pitdogg2 Posts: 14,623
    MrNaturl wrote: »
    You want to jumper the wide blade to the negative binding post.

    Ok that's what I was wondering. Isn't that how the p/b is set up inside the cabinet?

    Yes
  • So now the wide blade on the IC cable actually has a function. I'm having to make one and thought I'm not sure if it's even necessary to connect it before you guys solved this mystery. Thanks fellas!
  • pitdogg2pitdogg2 Posts: 14,623
    Will if you're making one why not switch it out for neutrik speakon connection? Much better and locks on.

    https://www.neutrik.com/en/product/nl4fx

    https://www.neutrik.com/en/product/nl4mp-uc

    I believe these are the correct ones.
    I just installed on my 2.3tl's but i do not still have the packages. I do however have a set of the top connectors as i went with these. vvvvvv

    https://www.neutrik.com/en/product/nl4frx
  • I may do that a little later. I picked up a couple cinch connectors to just get them connected. That looks like the way to go for sure.
  • VSAT88VSAT88 Posts: 723
    Best I know (mine are/were blade blade. now neutrik) the only need for putting in an extra wire is if you are going for the isolation transformer/AI-1 interconnect.
  • motorhead43026motorhead43026 Posts: 3,309
    edited September 29
    Hmmmmm I really misunderstood I guess when I tld mine I installed the jumper.

    Or it may not make a difference?
    Post edited by motorhead43026 on
    2 channel: Anthem 225 Integrated amp; Parasound Ztuner; TechnicsTT SL1350; Vincent PHO-8 phono pre; Marantz CD6005 spinner; Polk SDA2BTL's; Cables ZU Mission IC's, SC and power cords, all into a PS Audio Dectet Power center.

    All TV's sound enhanced by Polk Magnfi Mini's.

    Other; S60'S, M10 series II, M7C's, Hafler XL600 amp, RB-980BX, Parasound HCA-1500 amp , P5 preamp, all in storage. All speakers have had crossover rebuilds, resulting in a small fortune invested in Sonicaps, and tweeter upgrades.

    Political memes posted as fact and accepted as fact, are sign language of the ignorant, for the ignorant

    tonyb said " but even socialists can do a good thing here and there

    Social media makes dumb people dumber and smart people dumb then dumber.
  • VSAT88 wrote: »
    Best I know (mine are/were blade blade. now neutrik) the only need for putting in an extra wire is if you are going for the isolation transformer/AI-1 interconnect.

    So I won't need to modify anything besides the crossovers?
  • pitdogg2pitdogg2 Posts: 14,623
    MrNaturl wrote: »
    VSAT88 wrote: »
    Best I know (mine are/were blade blade. now neutrik) the only need for putting in an extra wire is if you are going for the isolation transformer/AI-1 interconnect.

    So I won't need to modify anything besides the crossovers?

    Correct but you'll never be able to use anything BUT a common ground amp. Most dual mono designs and all mono blocs are a no go.
  • pitdogg2 wrote: »
    MrNaturl wrote: »
    VSAT88 wrote: »
    Best I know (mine are/were blade blade. now neutrik) the only need for putting in an extra wire is if you are going for the isolation transformer/AI-1 interconnect.

    So I won't need to modify anything besides the crossovers?

    Correct but you'll never be able to use anything BUT a common ground amp. Most dual mono designs and all mono blocs are a no go.

    There goes those Mcintosh MC1.25KW's I wanted!
  • westmassguywestmassguy Posts: 6,445
    MrNaturl wrote: »
    No, they are single 3rd gen.

    Single board is 4th generation, not 3rd.
    Home Theater/2 Channel:
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  • gmcmangmcman Posts: 1,494
    Once they get all settled in, consider upgrading the internal wire if you haven't already.
  • MrNaturlMrNaturl Posts: 18
    gmcman wrote: »
    Once they get all settled in, consider upgrading the internal wire if you haven't already.

    Man this never ends LOL! You guys are mad geniuses... I guess I'll keep reading!

  • SchurkeySchurkey Posts: 1,896
    pitdogg2 wrote: »
    you'll never be able to use anything BUT a common ground amp. Most dual mono designs and all mono blocs are a no go.
    My experience is that "most" dual-mono amps are either common ground; or semi-common-ground with a pair of resistors between the negative terminals and chassis ground. A jumper wire across the negative terminals of each channel fixes the two-resistor problem.

    Some monoblocks can be connected the same way--Adcom 565s, for example. They're not a bridged/balanced design, so the negative terminals can be strapped to create a common ground.

    God help you if you connect the negative terminals of a bridged/balanced or inverted amplifier pair (stereo amp, or two monoblocks.)
  • pitdogg2pitdogg2 Posts: 14,623
    Schurkey wrote: »
    pitdogg2 wrote: »
    you'll never be able to use anything BUT a common ground amp. Most dual mono designs and all mono blocs are a no go.
    My experience is that "most" dual-mono amps are either common ground; or semi-common-ground with a pair of resistors between the negative terminals and chassis ground. A jumper wire across the negative terminals of each channel fixes the two-resistor problem.

    Some monoblocks can be connected the same way--Adcom 565s, for example. They're not a bridged/balanced design, so the negative terminals can be strapped to create a common ground.

    God help you if you connect the negative terminals of a bridged/balanced or inverted amplifier pair (stereo amp, or two monoblocks.)

    Did you even read the thread? My comment was to the fact that Blade/blade models cannot use non common ground amps. If he didn't connect the one blade to ground like pin/blade models have he could not use anything but common ground, was I wrong?
  • SchurkeySchurkey Posts: 1,896
    pitdogg2 wrote: »
    pitdogg2 wrote: »
    you'll never be able to use anything BUT a common ground amp. Most dual mono designs and all mono blocs are a no go.

    Did you even read the thread? My comment was to the fact that Blade/blade models cannot use non common ground amps. If he didn't connect the one blade to ground like pin/blade models have he could not use anything but common ground, was I wrong?
    When the amplifiers I described, have the negative terminals strapped like I describe, they ARE common ground.

    MY preferred amplifiers are dual-mono. I have blade-blade (SDA1B) speakers. A jumper wire makes my amplifier common ground.

    "Dual-mono" and "monoblock" amplifiers can sometimes be EASILY converted to common ground. The big deal is that they cannot be bridged/balanced or have one channel inverted like some Carver stereo amplifiers. Which means your original statement is not correct.
  • F1nutF1nut Posts: 42,918
    One should never assume a dual mono amp or mono blocks can have their negative binding posts strapped. Always consult the manufacturer first. If it is determined that they can be strapped keep in mind that it will raise the noise floor. Therefore, using the AI-1 or Dreadnought is a much better idea.
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