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    PAS 3X Dynaco

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    WPFW893FM

    Posts : 14
    Join date : 2019-05-12

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    Post by WPFW893FM on Sat May 16, 2020 12:02 pm

    I am looking at the inside of a PAS 3X So far I have taken some pictures and am thinking about how to best restore some of its possible problems and just keep it going. Saw a board for replacing the cans just looking for peoples experience and ideas.  Believe Triode Electronics does the board Sure others have it or similar.? Leave it at that for now. Do not know how to post my pics yet or I would.
    PeterCapo
    PeterCapo

    Posts : 794
    Join date : 2008-12-05

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    Post by PeterCapo on Sat May 16, 2020 1:37 pm

    If you are referring to a "cap board" that replaces the quad section capacitor as well as the filament supply, yes they perform well.  Trouble is, they can be difficult to get installed and working well.  It has a number of parts that would need to be assembled and then wiring it in could result in problems.  It is more straightforward to install a new quad section capacitor, if you really need one.

    What kind of problems are you having with your PAS-3X?  Are you sure it is a PAS-3X you have and not a PAS-3?  This document will help to sort that out: http://www.audioregenesis.com/documents/Dynaco%20PAS%203%20or%203X.pdf
    peterh
    peterh

    Posts : 1317
    Join date : 2012-12-25
    Location : gothenburg, sweden

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    Post by peterh on Sat May 16, 2020 1:49 pm

    PeterCapo wrote:If you are referring to a "cap board" that replaces the quad section capacitor as well as the filament supply, yes they perform well.  Trouble is, they can be difficult to get installed and working well.  It has a number of parts that would need to be assembled and then wiring it in could result in problems.  It is more straightforward to install a new quad section capacitor, if you really need one.

    What kind of problems are you having with your PAS-3X?  Are you sure it is a PAS-3X you have and not a PAS-3?  This document will help to sort that out: http://www.audioregenesis.com/documents/Dynaco%20PAS%203%20or%203X.pdf
    Or get one of the ready made boards if you find it difficult to assemble one.
    Benefits of these boards is that :
    - costs less then a new quadcap
    - it also replaces se rectifier and it capacitors
    The end result for future generations is that all caps are ordinary boardmounted
    types widely avaliable and no special versions.
    PeterCapo
    PeterCapo

    Posts : 794
    Join date : 2008-12-05

    PAS 3X Dynaco  Empty Re: PAS 3X Dynaco

    Post by PeterCapo on Sat May 16, 2020 3:25 pm

    peterh wrote:
    PeterCapo wrote:If you are referring to a "cap board" that replaces the quad section capacitor as well as the filament supply, yes they perform well.  Trouble is, they can be difficult to get installed and working well.  It has a number of parts that would need to be assembled and then wiring it in could result in problems.  It is more straightforward to install a new quad section capacitor, if you really need one.

    What kind of problems are you having with your PAS-3X?  Are you sure it is a PAS-3X you have and not a PAS-3?  This document will help to sort that out: http://www.audioregenesis.com/documents/Dynaco%20PAS%203%20or%203X.pdf
    Or get one of the ready made boards if you find it difficult to assemble one.
    Benefits of these boards is that :
    - costs less then a new quadcap
    - it also replaces se rectifier and it capacitors
    The end result for future generations is that all caps are ordinary boardmounted
    types widely avaliable and no special versions.

    Agree completely.

    At the same time, I continue to be concerned about reports of hum problems after installing a cap board.  It's not because there is anything wrong with a cap board - there should be no hum problem if properly installed.  However, my impression is that the recurring reports of hum problems involve integrating the cap board into the PAS grounding scheme.  I don't think you can drop-in a cap board and leave all the original ground wires where they are.  Successfully avoiding a hum problem would be greatly helped if the cap board comes with comprehensive instructions about how to rework the grounding.  They probably come with some installation instructions, but I tend to doubt they come with detailed instructions about reworking the grounding?  Anyway, that's been my impression.

    As an alternative possibility... try putting one 0.1µF polypropylene bypass capacitor in parallel with each section of the quad section capacitor.  Also, install a 10µF polypropylene capacitor at E16 of PC5 and also E16 of PC6 - I believe this is done in some Cary Audio gear.

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