ISO Schematic for LS70 crossover

jakeo25
jakeo25 Posts: 7
in DIY, Mods & Tweaks
Hello, links on this forum for the LS70 crossover are broken. Can someone repost?

Also if anyone has the upgrade parts list, this would be helpful.
Yamaha RX-V565
Polk LS50 modified with LS70 crossovers
Philips SBC-HP250
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Comments

  • skrol
    skrol Posts: 3,337
    Seems to work for me... https://us.v-cdn.net/5021930/uploads/attachments/4/6/7/2/8/18792.pdf
    Stan

    Main 2ch:
    Polk LSi15 (DB840 upgrade), Parasound: P/LD-1100, HCA-1000A; Denon: DVD-2910, DRM-800A; Benchmark DAC1, Monster HTS3600-MKII, Grado SR-225i; Technics SL-J2, Parasound PPH-100.

    HT:
    Marantz SR7010, Polk: RTA11TL (RDO198-1, XO and Damping Upgrades), S4, CS250, PSW110 , Marantz UD5005, Pioneer PL-530, Panasonic TC-P42S60

    Other stuff:
    Denon: DRA-835R, AVR-888, DCD-660, DRM-700A, DRR-780; Polk: S8, Monitor 5A, 5B, TSi100, RM7, PSW10 (DXi104 upgrade); Pioneer: CT-6R; Onkyo CP-1046F; Ortofon OM5E, Marantz: PM5004, CD5004, CDR-615; Parasound C/PT-600, HCA-800ii, Sony CDP-650ESD, Technics SA 5070, B&W DM601
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  • pitdogg2
    pitdogg2 Posts: 24,550
    It will not open for me in 3 different browsers.

    Open it and past it if you can.
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  • Clipdat
    Clipdat Posts: 12,589
    Attached.
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  • pitdogg2
    pitdogg2 Posts: 24,550
    Thanks
    On my phone mozilla, edge and armorfly all said they couldn't.
    Thought maybe the op could have similar problems.
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  • jakeo25
    jakeo25 Posts: 7
    edited January 2021
    Awesome! PDF is easiest opened on PC, Chrome ver 87.0.4280.88 (64 bit). Will update on progress of the upgrade ...
    Yamaha RX-V565
    Polk LS50 modified with LS70 crossovers
    Philips SBC-HP250
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  • jakeo25
    jakeo25 Posts: 7
    The Polk LS70 is a very similar speaker in size to the LS50, so swapped the terminal block. Found a pair on eBay.

    The new terminal block is bigger, so I drilled holes to cut a 3-3/4" height. The width was the same. The opening is done with a jigsaw to fit.

    kb40hsx6m4x3.jpg

    Use the existing mounting holes at the base of speaker cabinet, drill new holes for the top. Then feed the wires through and you grab them from the other side.

    dudz1h292dwe.jpg

    The top terminal feeds the tweeter, the bottom terminal feeds the pair of "UW" and "LW" 6.5" speakers. The final product, ready for tests: Mahler, Weather Report, Tangerine Dream, Frank Zappa, among others.

    iq2hjowa7ioy.jpg

    One added design of the LS70 crossover (as compared to the LS50) is it has two cascading low pass chokes, a passband for the UW and a lower passband for the LW.
    Yamaha RX-V565
    Polk LS50 modified with LS70 crossovers
    Philips SBC-HP250
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  • moodolski
    moodolski Posts: 1
    How'd the new crossover set up work out?
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  • jakeo25
    jakeo25 Posts: 7
    So initially I used a Yamaha 5.1 amp in bi-amp mode to drive the HF & LF separately. Generally good, but something always seemed off in the response even after replacing two drivers (speakers).

    For a completely unrelated reason, I swapped the Yamaha amp for a NAD C328 and boy what a difference! These speakers never sounded so good! So this was a total success.

    I should have remembered how my stepfather's Macintosh amplifier was far superior in reproducing sound. The amp is a key factor!

    Sorry for the delay in responding. :)
    Yamaha RX-V565
    Polk LS50 modified with LS70 crossovers
    Philips SBC-HP250
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  • pitdogg2
    pitdogg2 Posts: 24,550
    edited March 11
    jakeo25 Posts: 7
    4:52PM
    So initially I used a Yamaha 5.1 amp in bi-amp mode to drive the HF & LF separately. Generally good, but something always seemed off in the response even after replacing two drivers (speakers).
    1. No matter what marketing tells you,YOU CANNOT bi-amp with a receiver.
    2. The more channels you use on a AVR the less dedicated power you have going to the speakers.
    3. You by thinking you were adding more power doing what you did ACTUALLY decreased the available power the receiver had.
    4. Look at the receiver power specs, see where it says such and such power @ 2ch at what maybe 1khz not 20hz-20khz most likely. What that means is you only have that rated power AT 2 channels. Most of modern AVR's rated at say 120 per channel are down to 40-50 per channel with 5-6 channels playing.
    5. It's easier to blow drivers with not enough current or watts. By hooking the receiver as you did it's easier to clip the signal which will toast something.
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  • F1nut
    F1nut Posts: 49,784
    Worth repeating.
    No matter what marketing tells you,YOU CANNOT bi-amp with a receiver.
    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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