Which xover is correctly assembled?

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neskahi2
neskahi2 Posts: 35
Both of these xovers are supposed to be B2000A. For 2.3's. The top one is actually labeled B2000A, 2.3. The bottom one is only labeled 2.3.
I purchased 2 of the top ones off eBay years ago.
The bottom one I purchased directly from Polk around the same time.
Both have 4 resistors. As they should.
Notice the caps in the center of the board are reversed. I think I'm correct in saying the top one is good and the bottom one is a fluke./Users/jimcook/Pictures/Photos Library.photoslibrary/originals/A/A431742A-B7B7-4367-B067-A990413A6BB2.jpegu64bkc958e3t.jpeg
Post edited by neskahi2 on

Best Answer

  • pitdogg2
    pitdogg2 Posts: 24,783
    edited June 2023 Answer ✓
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    neskahi2 wrote: »
    So what's going on therein your pics? Two differently assembled xovers? And whats "OCD tilted?"
    I'm speaking of 2.3's. NON TL.
    My XO's from the factory for my 2.3tl pair.
    As you can see assembled different enough to make them pretty much unlistenable. Paralleling Mylar caps with electrolytic, paralleling electrolytic with electrolytic close to the value yet with the +/- tolerance they were off enough to make them suck to listen to.

    Yours would be easy enough to just switch the caps to the correct location, yes it's wrong.
    If you're going to parallel caps it is advisable to get them as close to half of each value to make the value needed. Paralleling the 12uf mylar with the 4.2uf electrolytic basically made the 4.2uf a bypass cap, not a good one at that. Paralleling the two electrolytic caps with the +/- values of each unless tested to make sure the value was within the +/- tolerance they could have been (were) way off from where they needed to be for the value needed.

    The OCD comment was just a joke, don't get your pants all twisted😉. I'm just for reference showing you that many others were a nightmare assembly, mine for example.
    I knew parts came from Mexico, drivers, caps etc, I wasn't aware the XO's were assembled in Mexico. Honestly if the board was upsidedown and you were doing hundreds a day, it could happen. Obviously it did!

Answers

  • Gardenstater
    Gardenstater Posts: 4,242
    edited June 2023
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    Well you don't show the trace side of the circuit boards, so hard to say. Are they the same? They could have made a change but that would be admittedly weird.

    Is that blue cap next to the 12uF yellow mylar cap a 20uF electrolytic in both cases?
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • neskahi2
    neskahi2 Posts: 35
    edited June 2023
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    Trace side is the same and values are correct. They are just reversed in position. I seem to get vertigo when
    trying to figure this out from the schematic. It's likely a simple assembly error but need to make sure before
    offering for sale. So I hope the top one is correct.
  • Gardenstater
    Gardenstater Posts: 4,242
    edited June 2023
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    In the lower PCB is the blue cap connected at one leg to one of the legs of the 750pf silver mica cap and also to one leg of the polyswitch? If so it is dead wrong. But I'm blind here without being able to see the other side.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • neskahi2
    neskahi2 Posts: 35
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    Me thinks you are correct. Waiting on the cloud to load better pics.
  • pitdogg2
    pitdogg2 Posts: 24,783
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    So which speakers 2.3 or 2.3tl?
    Soo this should get you OCD tilted.
    My 2.3tls from factory. No wonder the original owner said each speaker sounded differently and they didn't sound like the pair he heard at the stereo shop. FTR the original owner listened to him for 3 months and then put them in a closet for 20 years until I bought them. I too wondered why I couldn't get them dialed in until I redid the crossovers and seeing what the original crossovers looked like.

    14wjidsireph.jpg
    5h52hrx55zw6.jpg
    6r0361oqd5u0.jpg
    480x3fjdcf1v.jpg
    padwr9na771e.jpg
    The traces you needed to see.





  • neskahi2
    neskahi2 Posts: 35
    edited June 2023
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    So what's going on therein your pics? Two differently assembled xovers? And whats "OCD tilted?"
    I'm speaking of 2.3's. NON TL.
    Post edited by neskahi2 on
  • neskahi2
    neskahi2 Posts: 35
    edited June 2023
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    Top two purchased from eBay. Bottom from Polk.
    /Users/jimcook/Pictures/Photos Library.photoslibrary/resources/derivatives/B/B476C76F-2123-4047-A363-0759403C0E02_1_102_o.jpeg7kar1l5skotq.jpeg
    /Users/jimcook/Pictures/Photos Library.photoslibrary/resources/derivatives/9/979CF6B8-323D-4623-B0B7-8FBF657EF78A_1_102_o.jpegpu5n68ccqh55.jpeg
  • Gardenstater
    Gardenstater Posts: 4,242
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    So you flipped them left to right but not top to bottom I see. Well it sure looks to me like the one you got from Polk is incorrect and they reversed those two caps like you said.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • neskahi2
    neskahi2 Posts: 35
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    I think so too. They were assembled in Mexico and maybe Pedro called in sick and Jose had a hangover when put on the assembly line. I don't know. But I feel comfortable in advertising the 2 from eBay as 2.3. The other one has no inductor so it's gonna be trash. Any other comments are welcome and thanks.
  • neskahi2
    neskahi2 Posts: 35
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    Another Polk owner sent this pic and confirmed that our observations are correct. This came from his 2.3's.
    [rotate 180*]

    /Users/jimcook/Library/Messages/Attachments/85/05/4E3680DF-48D9-4CEC-A528-FB3BA17A2D31/image000000.jpg59uxez61rfqr.jpg
  • msg
    msg Posts: 9,699
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    Wow. I better check my 2.3TLs, which have been parked pending the upgrades. I never experienced any obvious SDA with them, and they sounded thin and just... off. Just not that great. I checked everything but the crossovers. No wiring out of phase, no leaks, etc. I've loosely suspected something crossover related as the cause, but nothing this big. Good info here.
    I disabled signatures.
  • neskahi2
    neskahi2 Posts: 35
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    "The OCD comment was just a joke, don't get your pants all twisted"
    Pants are ok. I just truly didn't know what OCD was until my wife told me. LOL

    Pittdog2. It's interesting about your xovers. I once had a set of 1.2TL that I bought from guy in TX.
    When I asked why he was selling he said 'I just could never get into them'. Then he played his 80 watt tubed mono's
    into some huge horns I never heard of and figured that was why he was not enjoying the 1.2's. Very nice sounding they were.
    When I got the 1.2TL home I experienced a lack of 'something'. Never figured it out. Everything was working but
    not everything was there. I sold those. [not the set JayCee bought from me years ago. those were nice]
    So maybe there are some variables like you are finding. Maybe someone in assembly had an incorrect schematic
    or sabotage during a worker strike. Let us know what happens after you fix that xover.
  • neskahi2
    neskahi2 Posts: 35
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    Regarding the 'Assembled in Mexico' thing. Years ago part of my sales territory was Mercury Marine in
    Stillwater, OK. They had recently moved their wiring harness assembly to Mexico. Then they simply had too many
    problems and warranty claims that it was necessary to bring it back to the states. Of course this was
    top secret and need to know basis only but several people confirmed the story.
    Anyone that owned a Big Block GM in a boat from that era, mid to late 90's, may know what I'm talking about.
    Fuel injected with a big multi pin connector on top of intake. Just sayin.
  • pitdogg2
    pitdogg2 Posts: 24,783
    edited June 2023
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    No need to fix. I completely rebuilt them from the ground up with gimpod boards, Mills, Sonicaps and all new inductors. They're magical now ;);)
    Those old XO's are now just sitting in a box.