What value resistors in Monitor 5A?

stevepe
stevepe Posts: 4
edited July 2012 in Vintage Speakers
Hi All,

First post here. I want to upgrade the crossovers on some 5A's I just got, but I'm wondering what's up. I'm seeing contradictory values for the resistors. Other guys' 5A crossovers have different values, and so do my Monitor 7's.

These 5A's have a 2.5 ohm and a 6.2 ohm resistor (both 10% 5W)

I've seen some 5A's with 2.5 and 2.7. My Monitor 7's have 2.5 and 4.5 and have the same woofers as my new 5A's. (MW6500 and peerless tweeters.) So what about the 6.2 ohm resistors?

I intend to upgrade with a 12uf 1% poly cap, and for the other, parallel two 17uf electrolytics with a poly bypass. (I did this on my 7's)

Why the discrepancy?

Thanks,
Steve
Post edited by stevepe on
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  • westmassguy
    westmassguy Posts: 6,850
    edited July 2012
    stevepe wrote: »
    Hi All,

    First post here. I want to upgrade the crossovers on some 5A's I just got, but I'm wondering what's up. I'm seeing contradictory values for the resistors. Other guys' 5A crossovers have different values, and so do my Monitor 7's.

    These 5A's have a 2.5 ohm and a 6.2 ohm resistor (both 10% 5W)

    I've seen some 5A's with 2.5 and 2.7. My Monitor 7's have 2.5 and 4.5 and have the same woofers as my new 5A's. (MW6500 and peerless tweeters.) So what about the 6.2 ohm resistors?

    I intend to upgrade with a 12uf 1% poly cap, and for the other, parallel two 17uf electrolytics with a poly bypass. (I did this on my 7's)

    Why the discrepancy?

    Thanks,
    Steve
    Polk had many incarnations of the M5s. I ran into the same problem when recapping my M5s which were an early model. None of the published schematics matched my crossover, nor did the listed drivers match what I had. Mine came with SL1000 8 ohm Polk Tweeters, and MW6500 8 ohm woofers. All the schematics show an MW6502 which is a 4 ohm woofer. Your best bet IMHO, is to replace with the exact same value. The Peerless Tweeters required different values than the SL1000/2000/2500 that came later.
    Providing they're in perfect working order, the Peerless have a wonderfull sound to them, and no need to attemp to upgrade them to the RDO series.
    BTW, while you have everything open, you might want to consider upgrading the resistors with some quality Mills resistors. The Wire-wound ceramics Polk used were mediocre at best.
    Home Theater/2 Channel:
    Front: SDA-2ATL forum.polkaudio.com/discussion/143984/my-2as-finally-finished-almost/p1
    Center: Custom Built forum.polkaudio.com/discussion/150760/my-center-channel-project/p1
    Surrounds & Rears: Custom Built forum.polkaudio.com/discussion/151647/my-surround-project/p1
    Sonicaps, Mills, RDO-194s-198s, Dynamat, Hurricane Nuts, Blackhole5
    Pioneer Elite VSX-72TXV, Carver PM-600, SVS PB2-Plus Subwoofer

    dhsspeakerservice.com/
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  • pitdogg2
    pitdogg2 Posts: 25,446
    edited July 2012
    westmassguy wrote: »
    BTW, while you have everything open, you might want to consider upgrading the resistors with some quality Mills resistors. The Wire-wound ceramics Polk used were mediocre at best.

    Yes Mills resistors to replace factory and forget that electrolytic and poly bypass just put in good poly's and call it a day. clearity cap or Sonicap are highly recommended
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