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  1. #1

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    Default Tell me Im wrong on the TL model

    http://vr3mods.com/uploads/SDA_Handbook_2011_Rev2.pdf

    Look at page 102 schematic of the 1.2 TL
    Isn't the ground of one channel simply grounding the "dimensional" channel?
    If the amps grounds are common, how are we getting the true dimensional sound meant for the SDA series?

    Look at page 100 on the older SRS model, this one is actually sending opposite L and R channels over the cross connect wire.

    Have we been duped on the later 1.2 TL series?

  2. #2

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    You're wrong.
    '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 turd by the clean end."

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    Haha! Straight forward and to the point. Love ya Jesse.
    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."

    "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

  4. #4

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    So your saying the schematic is wrong? Follow the wiring to the 2 pin socket
    If the input binding posts are jumpered, then all the grounds are common. The left speaker is simply sending the ground over to the right speaker and vice versa! Maybe that has some sort of effect from the speakers back emf? All depends on the speaker cable length.....
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    Last edited by deafbykhorns; 05-15-2014 at 06:58 AM.

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    Or are the pins not being swapped like the earlier series? If so, this is almost like simulating a center channel and basically puts the left and right speakers in series with a choke center tap. I wonder if I can simulate this in spice, hmmm........

  6. #6

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    This would be both channels of the dimensional channel and interconnect. This seems to be the most dramatic change in the SDA line. The ground is redundant and probably insures your polarity is correct, otherwise you would have no sound since it would short the channel that has wrong polarity. If both channels polarity were wrong, it would combine L+R channel.
    Technically the ground is not needed if the polarity is correct unless the wires were twisted to serve as a shield.
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    Last edited by deafbykhorns; 05-15-2014 at 08:19 AM.

  7. #7

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    To the OP. you are wrong but at the same time what you are seeing is correct; you are just not understanding the circuit electrically. i will try but I am always easily understood.

    The negative signal side of the wiring (ground) is not really a ground in the dimensional circuit. The negatives from each cabinets dimensional circuit is sent to the opposite cabiinets negative signal wire. This inverts the polarity from one cabinet to the other and allows only the difference between the two channles to be played through the dimensional drivers. This type wiring is essentially bridgeing the amplifier into a single channel amplifier, but only on the dimensional circuit. The dimensional inductor bypasses this inverted circuit for the bass portion of the signal only so as to allow proper bass output from the system. the dimensional circuit operates only from the midbass to upper midrange frequencies, except on early SDA's with dimensional tweeters.
    If con is the opposite of pro, is Congress the opposite of Progress?!


    Monitor 5Jr, Monitor 5, RTA12, SDA 2A, 1c, SRS, 1.2TL, Atrium.

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    Quote Originally Posted by Mr. Bubbles View Post
    To the OP. you are wrong but at the same time what you are seeing is correct; you are just not understanding the circuit electrically. i will try but I am always easily understood.

    The negative signal side of the wiring (ground) is not really a ground in the dimensional circuit. The negatives from each cabinets dimensional circuit is sent to the opposite cabiinets negative signal wire. This inverts the polarity from one cabinet to the other and allows only the difference between the two channles to be played through the dimensional drivers. This type wiring is essentially bridgeing the amplifier into a single channel amplifier, but only on the dimensional circuit. The dimensional inductor bypasses this inverted circuit for the bass portion of the signal only so as to allow proper bass output from the system. the dimensional circuit operates only from the midbass to upper midrange frequencies, except on early SDA's with dimensional tweeters.
    Adding to this a bit:

    The non-AI-1 interconnect cable has nothing connected to the blade terminal, therefore it can be utterly ignored.

    The pin terminals transfer current/voltage--therefore power--between the negative sides of the dimensional drivers; whichever dimensional channel has higher voltage after the crossover and inductor filters out the low-bass and treble, sends current to the negative side of the other speaker's dimensional driver. Since the transfer occurs to the negative side of the driver, it's inverting polarity.

    The AI-1 circuit functions essentially the same. The pin terminal sends the voltage/current through the transformer winding instead of directly to the other speaker cabinet. The other end of each transformer winding finds it's ground at the blade terminal. Each cabinet gets it's voltage/current signal through the transformer coupling, but it's still a moment-by-moment balance of power from each speaker that results in current being shuffled back and forth between the negative sides of the dimensional drivers.

  9. #9

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    Schurkey

    You are correct, that's what had me confused since all the older SDA models used both pins.
    I checked the cable and the blade terminal is open on one end, the other end is connected (probably for shielding).

    Mr Bubbles,

    Your correct as well, follow the circuit I sketched, the two channels are interconnected via the 40uf caps and part of the filter network.

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    Sda is so cool it is really nice how all that was figured out so that it does what it does so well.
    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

  11. #11

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    Quote Originally Posted by PolkieMan View Post
    Sda is so cool it is really nice how all that was figured out so that it does what it does so well.
    Probably a lot of trial and error....
    I did find a pair of 1.2's
    After studying the schematic, they could be easily upgraded to TL status as they already have the SL3000 drivers installed.
    They are a little beat up, one tweeter has been changed to a SL2000, one of the tops are missing and they need refinishing.
    I'm guessing about 30 hrs labor, maybe $300-$400 in parts, end result would be a pair of TL's....
    May offer about $700???

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    I got mine for $500.00, and the guy delivered them for me.
    The Gear... Carver "Statement" Monoblocks, Polk Audio "Signature" Reference Series 1.2TL with complete mods, Polk audio AB700/800 "in-wall" surrounds, Dodd Audio MLP, Pioneer Elite SC-65, Peachtree I-DAC, Oppo BDP-93, Yamaha PX-3 Turntable, with Sumiko BPS EVOIII, Pioneer PDD 9MkII SACD Player, SimAudio moon 110lp phono preamplifier

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  13. #13

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    Quote Originally Posted by nooshinjohn View Post
    I got mine for $500.00, and the guy delivered them for me.
    That sounds like a heck of a deal, did you change them to TLs?

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