Crossover experts Monitor 10 crossover question

geppy1
geppy1 Posts: 3,075
edited February 2011 in Vintage Speakers
It appears from the 5 or 6 pairs of Monior 10 crossovers I have looked at(serial between 70,000 and 123,000) they all have the same cap values and same resistor values (2.7 and 2.5) This incudes early 10s (Denmark Peerless) 10As (US made Peerless) and early 10Bs (SL1000) The only difference is they started switching to electrlytics in 83. I have a pair of early 10B crossovers one is one type of cap the other has electos.

Here is my question Below is a picture of a 10A crossover (which i believe my early 10 looked like) and one of mine from my early 10s. About 17 years ago i was talking to ken (the man) at Polk and he said just send me your crossovers. He redid them The one with the big yellow caps are the ones he redid. The values are the same but he used a different type of cap in one postion and the resistor is a very long 2.7 and then a 2.0 not a 2.5 What did he really do here?? I would like to understand 1) The one cap change 2) the long 2.7 and 2.0 verse the short 2.7 and 2.5 on the priginal Thanks,keith
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  • FTGV
    FTGV Posts: 3,649
    edited June 2010
    geppy1 wrote: »
    What did he really do here?? I would like to understand 1) The one cap change 2) the long 2.7 and 2.0 verse the short 2.7 and 2.5 on the priginal Thanks,keith
    1)Used a higher quality cap
    2)The longer resistors will be higher wattage and there will be slightly less hi frequency attenuation with the 2.0 vs 2.5 ohms.
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  • geppy1
    geppy1 Posts: 3,075
    edited June 2010
    I figured the cap was bettetr. I can never remember which is mylar and which is silver mica The yellow or the black and red?? If?? i wanted less high frequencies i would replace the 2.0 with a 2.5??
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  • FTGV
    FTGV Posts: 3,649
    edited June 2010
    geppy1 wrote: »
    I figured the cap was bettetr. I can never remember which is mylar and which is silver mica The yellow or the black and red??
    The yellow ones are Mylars and I assume the black ones are electolytics.There are no Silver Mica's in this xover but they are usually brown and are only available in very small values.
    if I wanted less high frequencies i would replace the 2.0 with a 2.5??
    Yes but .5 ohms will only amount to a fraction of a db in level change.Also here the resistor has a capacitor in parallel with it which forms a contour network.The capacitor effectively limits the range over which the resistor will attenuate the tweeters output.The result being that the highest frequencies will not recieve the same amount of attenuation as the lower frequencies in the tweeters operating range.This would compensate for a rolled off top end in the M10 tweeters response.e .
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  • geppy1
    geppy1 Posts: 3,075
    edited June 2010
    Bottomline, overall in theory how would this crossover change the sound compared to the stock one?
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  • FTGV
    FTGV Posts: 3,649
    edited June 2010
    geppy1 wrote: »
    Bottomline, overall in theory how would this crossover change the sound compared to the stock one?
    In theory the better cap should improve hi frequency detail.The higher wattage rating on the resistor will make no difference.And IMO since the .5 ohm reduction in resistance equates to only a fraction of a db difference in level it should be imperceptible.
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  • geppy1
    geppy1 Posts: 3,075
    edited June 2010
    Then it appears that he upgraded them slightly?? I am sure he had the choice to put in a 2.5 but must have had a reason for putting in the 2.0 and that type of cap where he did.
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  • Outfitter03
    Outfitter03 Posts: 563
    edited January 2011
    Spam Post Reported.
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  • geph0007
    geph0007 Posts: 9
    edited January 2011
    What does that mean??
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  • NotaSuv
    NotaSuv Posts: 3,852
    edited January 2011
    Outfitter03 wrote: »
    Spam Post Reported.

    ?????????????
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  • dcmeigs
    dcmeigs Posts: 708
    edited January 2011
    If it was done at Polk, don't you suppose they used the caps they had in inventory for their current production? Caps drift in value and fail altogether in time. I think they identified a bad cap and changed it. If the values are close but not exactly the same I think it's because that was the value they were using for current production.
    The world is full of answers, some are right and some are wrong. - Neil Young
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  • pitdogg2
    pitdogg2 Posts: 25,450
    edited January 2011
    you had a spam infiltrater after post #7 it got zapped
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  • jcandy
    jcandy Posts: 501
    edited February 2011
    If there is someone in the San Diego/Irvine area who would like a significant crossover makeover for their vintage Monitor series (5jr, 5,7,10) speakers, I'm willing to donate my time and measurement equipment in order to do a complete redesign. The goal would be to do more than simply replace L/C/R components with new, higher-quality parts. Rather, I would try to improve the actual filter properties (by reducing the woofer inductor DCR, adding some contouring to the tweeter HP section, etc). Its no-risk, because you could keep the old crossover and swap the new one in/out as desired.
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