Problem with crossover upgrade - Monitor 10s

weinberz
weinberz Posts: 6
edited July 2011 in Speakers
Hey all,

I bought a kit off ebay to upgrade the xovers on my Monitor 10s and appear to have messed something up. I've only done one speaker so far, but the tweeter on that speaker is no longer producing any noise, and the mids and bass sound...off. I'm gonna wait til tomorrow to go back and check my solder joints, but what I'm more worried about is that I think I might have inadvertently burned some of the PCB in the soldering process. If I damaged the PCB, specifically the contacts for the cap and one of the resistors in the RC contour network, could that be the cause of my issues? Has anybody else had a similar problem and know what the cause might be? Any thoughts?

Thanks!
Post edited by weinberz on
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Comments

  • Outfitter03
    Outfitter03 Posts: 563
    edited July 2011
    Welcome to club Polk. First off congratulations on owning the Monitor 10s and it will help if you post some pictures of both the speakers and the crossovers for clarity.

    Do you have a volt meter. Taking some resistance readings from the binding post to the input to the capacitor and also from the output of the capacitor to the end of the wire (REMOVED) from the tweeter input would help trouble shoot if you have continuity problems.

    If you type Monitor 10 into the advanced search field and select vintage speakers and DIY you should pull up several threads that come complete with pictures detailing how to do these upgrades. If you have damaged the PCB board all is not lost you may just need to use a section of 16 gauge wire to make a solder connection to the next component directly. This is why a picture would help. I don't know if these kits come with a schematic, but you can find one in a sticky at the top of vintage speaker format.

    Welcome again.
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  • weinberz
    weinberz Posts: 6
    edited July 2011
    Thanks for the warm welcome, Outfitter!

    I took some resistance readings - from the post to the beginning of the cap in the high pass filter reads as 2.7ohms, but from the post to the end of that same cap reads as open. Does that mean I've got a bad capacitor?
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  • weinberz
    weinberz Posts: 6
    edited July 2011
    Well, I decided to test everything after repairing a cold solder joint (on the cap in the RC contour network, didn't touch the cap in the high pass filter and everything seems to work great. Out of curiosity, why would I get an open reading between the post and the end of the cap in the high pass filter, yet everything would work?
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  • cristo
    cristo Posts: 231
    edited July 2011
    Caps don't pass direct current, so you will get an open circuit across one testing with a multimeter.
    They pass ac current (like music signal) better and better as the frequency rises, hence
    their utility in a high pass circuit.
    cristo

    NAD C 545BEE cd player, Philips AF877 turntable / Shure V15V-MR with JICO SAS stylus,
    Tascam 122 mkIII cassette deck, Harman Kardon 3480 receiver, Terk FM-50 antenna in the attic,
    Soundcraftsmen SE550 stereo equalizer, Polk Monitor 10a speakers
    (with Sonicraft/Solen/Mills crossover rebuild)
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  • dorokusai
    dorokusai Posts: 25,577
    edited July 2011
    Don't buy the upgrade kits for any Polk Audio loudspeaker off eBay.
    CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
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