SDA XO expertise requested

Qboneus
Qboneus Posts: 15
edited January 2009 in Vintage Speakers
I have almost finished recapping\re-resistoring my SDA 1a
I have one issue I need to tend to however; it is listed as A on the schematic i posted and can also be physically be viewed in the first Picture i posted. (schematic also shows a different value than was installed stock i have a 1000pf)?
I have replaced the stock 5 watt resistors with mills 12w and all the other caps with kimberkaps of the requisite values.
However i was unable to locate a .5uf as was stock and used a .47uf kk in its place.
I have NOT as of yet replaced this .5uf's bypass (i am thinking this is a bypass I want to keep) and was going to do this tonight.

I was thinking of using a pair of panasonic pps ech-s films with a value of .022uf for a total add-in\bypass of .044uf using the pair of ECh-S's.
this added to my .47uf KK should put me right within the stock range for this application at .514uf, To my thinking.:confused:

So the questions,
Is my thought process flawed about this application needing to keep the BP? (even though I probably need to do this anyway to get my values back within specs)

Are panasonic PPS film ECH-S capacitors worthy of being utilized as a bypass in this XO?

Does this value make sense or should I be looking at a different path to get the values I require?

Thanks in advance,
Tal
Post edited by Qboneus on
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Comments

  • ben62670
    ben62670 Posts: 15,969
    edited January 2009
    Omit the 750pf cap. Polk may have used a 1000pf in its place. That cap should not be used when doing the upgrade.
    Enjoy
    Ben
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • Qboneus
    Qboneus Posts: 15
    edited January 2009
    Should i add .03uf of these film caps to bring the .47uf up to the stock .5uf values?
    I am terrible at math but according to my guesstimate this puts me at about 6%(with .47's), getting awful close to 10% for my tastes.
    Anything else I should be looking at renewing?
    Thanks for the advice,
    tal
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  • ben62670
    ben62670 Posts: 15,969
    edited January 2009
    The .47 is fine. Let us know how you like the Kimbers.
    Ben
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • Systems
    Systems Posts: 14,873
    edited January 2009
    Qboneus wrote: »
    Are panasonic PPS film ECH-S capacitors worthy of being utilized as a bypass in this XO?
    I have used these in active crossovers and have been well pleased with them,but have never tried them in a passive xover.They should work fine in that contour part of the circuit(the.5uf is not a bypass).I would use 100volt spec.
    Testing
    Testing
    Testing
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  • F1nut
    F1nut Posts: 50,746
    edited January 2009
    As stated, the .47uF is fine and is not a bypass cap. Remove both 750pF bypass caps as you no longer need them.

    Kimber Kaps? Auricap made those, but I thought they stopped selling them.
    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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