SDA2 B crossover question

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  • Gardenstater
    Gardenstater Posts: 4,182
    edited February 2021
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    Picture of the board location would help, showing relative size of caps to each other and the holes. Generally you want to keep the caps equal in size, or so I have heard here anyway.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
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  • pitdogg2
    pitdogg2 Posts: 24,559
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    Do need 40uf? Why do you need to attach to 30uf?
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  • F1nut
    F1nut Posts: 49,794
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    alandharper wrote: »
    So.... soldering question. Of course I left the worst for first. I put the 30 cap on top. When I put the 10 under the board, can I solder the 10 cap to the 30 caps legs? Not sure how to get them Both through the hole?

    Yes, you can extend the 10uF leads to the 30uF on the top of the board or attach the 10uF leads with a soldered dog leg connection to the 30uF leads poking through the bottom of the board.
    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

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  • alandharper
    alandharper Posts: 40
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    Thanks again. I thought it was SOP to have the 30 on top and 10 underneath. I have it tidy, but I want it to be as right as it looks. I have the 194 tweeters to go in so I might be considering deleting the poly switch.
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  • Gardenstater
    Gardenstater Posts: 4,182
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    Another thing you could do is make a couple new holes in the PCB underneath for the 10. If you have a Dremel tool and the small drill chuck that's one way to do it. There are also these diamond points from Harbor Freight in various sizes which I have had good luck with. Some of the smaller sizes are missing but you get the idea. They say the best solder joint is the one that uses the least solder. I'm still on the learning curve.


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    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
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  • alandharper
    alandharper Posts: 40
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    OK. I think that part is solved. I have two opinions needed on sealing drivers/radiators. Should I keep the foam and use the rope insulation or just insulation? And hope much of a sonic difference is the dynomat on the baskets?
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  • alandharper
    alandharper Posts: 40
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    Not hope much, how much, sorry.
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  • TennMan
    TennMan Posts: 1,264
    edited February 2021
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    alandharper wrote: »
    I have the 194 tweeters to go in so I might be considering deleting the poly switch.
    Get rid of the poly switch. If you have an amp that can supply plenty of clean power you won't need it.

    • SDA 2BTL · Sonicaps · Mills resistors · RDO-198s · New gaskets · H-nuts · Erse inductors · BH5 · Dynamat
    • Crossover upgrades by westmassguy
    • Marantz 1504 AVR (front speaker pre-outs to Adcom 555)
    • Adcom GFA-555 amp · Upgrades & speaker protection added by OldmanSRS
    • Pioneer DV-610AV DVD/CD player
    • SDA CRS+ · Hidden away in the closet
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  • pitdogg2
    pitdogg2 Posts: 24,559
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    Do not use moretite or rope caulk
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  • alandharper
    alandharper Posts: 40
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    Uh OH. Old info I fear. I want something with a tight seal, but not permanent. Anyone with fresh ideas?
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  • alandharper
    alandharper Posts: 40
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    looks like Armacell is the way to go. I also read the thread on poly switch removal and substitution. I think with my hearing and my room I am going with a jumper.
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  • Gardenstater
    Gardenstater Posts: 4,182
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    Matthew Polk advises in the SDA Handbook that the thinnest gasket material that will make a seal is best. Interpretations abound. I would highly advise using the Dynamat Xtreme on the baskets. I immediately noticed a much more pleasing sound with drums such as toms and congas. Much more *thwack* sound is the only way I can really think of to describe it.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
    · Share on FacebookShare on Twitter
  • alandharper
    alandharper Posts: 40
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    Well I hope someone else learns from all this discussion as well. I am ready to go forward. I still am not thrilled about the stock mounting of the CX board. Seems a bit rattily to me. I might do something different there. Many thanks to all who educated me.
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  • invalid
    invalid Posts: 1,276
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    You could also order some hurricane nuts at parts express for under $10 for 50 of the to mount the drivers and passive for a better deal than the stock phillips screws.
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  • alandharper
    alandharper Posts: 40
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    Good evening . I finished my speakers and I have a couple of questions. When listening to the outer speakers on each side, they don't seem to have the same tonal qualities. Is this normal or has anyone ever compare them?should they sound similar ? They sound great as a pair. Lots of clarity and bass for days. Maybe Im just looking for something. Not sure.
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  • alandharper
    alandharper Posts: 40
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    I guess I should have stated that the right speaker is the one that sounds a but dull maybe. Just on that outer speaker. I know its out of phase and so on, but I was thinking the outer speakers on each side would sound similar.
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  • TennMan
    TennMan Posts: 1,264
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    Use this troubleshooting guide to determine if the outer (dimensional) drivers are working correctly.
    https://us.v-cdn.net/5021930/uploads/attachments/4/6/7/2/8/47379.pdf
    • SDA 2BTL · Sonicaps · Mills resistors · RDO-198s · New gaskets · H-nuts · Erse inductors · BH5 · Dynamat
    • Crossover upgrades by westmassguy
    • Marantz 1504 AVR (front speaker pre-outs to Adcom 555)
    • Adcom GFA-555 amp · Upgrades & speaker protection added by OldmanSRS
    • Pioneer DV-610AV DVD/CD player
    • SDA CRS+ · Hidden away in the closet
    · Share on FacebookShare on Twitter
  • F1nut
    F1nut Posts: 49,794
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    The dimensional drivers play at about half the volume.
    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

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  • Gardenstater
    Gardenstater Posts: 4,182
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    How are you testing them? One gets L-R and the other gets R-L. Have you tried swapping them? How do they measure in DCR (Ohms)?

    Play some white noise through each one and check the freq resp spectrum with a phone app like Advanced Spectrum Analyzer Pro.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
    · Share on FacebookShare on Twitter
  • VSAT88
    VSAT88 Posts: 1,227
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    @Gardenstater, I appreciate the suggestion above ^. Never even crossed my mind that there could be a spec a. app !
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