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The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Tubes4hifi VTA tube amp and preamp kits and all Dynakitparts.com products


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Wotan
kenmwallace
6 posters

    Quad filter Capacitor Reconstruction with Individual Internal Capacitors

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    kenmwallace


    Posts : 2
    Join date : 2021-12-18

    Quad filter Capacitor Reconstruction with Individual Internal Capacitors Empty Quad filter Capacitor Reconstruction with Individual Internal Capacitors

    Post by kenmwallace Sun Dec 19, 2021 12:40 am

    I wanted to replace the filter capacitors with known-good new caps. But, I also wanted to maintain the original appearance.
    My solution was to extract the internal contents of the quad capacitor can by slotting the crimp and peeling it back so the molded plastic terminal bulkhead could be removed.
    The terminal bulkhead was drilled with small holes next to each terminal stud. The positive leads were passed through the holes so they could be wrapped around the studs.
    The four new capacitors had their negative leads joined together and threaded through a hole in the center of the bulkhead.
    This is my first post, so please bear with me if the images are not in the correct sequence.

    Quad filter Capacitor Reconstruction with Individual Internal Capacitors Dynaco10
    Quad filter Capacitor Reconstruction with Individual Internal Capacitors Dynaco12
    Quad filter Capacitor Reconstruction with Individual Internal Capacitors Dynaco11


    Quad filter Capacitor Reconstruction with Individual Internal Capacitors Dynaco14
    Quad filter Capacitor Reconstruction with Individual Internal Capacitors Dynaco13

    jimafm, Brian Malman, steve46, kFish and sayntjack like this post

    Wotan
    Wotan


    Posts : 31
    Join date : 2018-02-11

    Quad filter Capacitor Reconstruction with Individual Internal Capacitors Empty Re: Quad filter Capacitor Reconstruction with Individual Internal Capacitors

    Post by Wotan Wed Dec 29, 2021 11:10 am

    It doesn't matter particularly what order the photos are in, the idea is clear, and worthwhile. Electrolytic capacitor technology has improved enormously since these quad caps were common. If there's no exact Authenticcap or the like match for what you are restoring this is good information. 500 volt caps are not that common nowadays, though, and many of the amp circuits require 550 or more, in which case you'd have to use a series combination with equalizing resistors. Especially if you're running them on modern 120 line voltage (I found that out the hard way).

    The only possible newbie error is you're apparently posting in the photos of your Dynaco system section but I don't think that's important.
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    sayntjack


    Posts : 10
    Join date : 2020-11-26

    Quad filter Capacitor Reconstruction with Individual Internal Capacitors Empty Re: Quad filter Capacitor Reconstruction with Individual Internal Capacitors

    Post by sayntjack Wed Dec 29, 2021 12:46 pm

    You have put a lot of thought and work into this.  Well Done!
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    tubed1


    Posts : 29
    Join date : 2012-01-03

    Quad filter Capacitor Reconstruction with Individual Internal Capacitors Empty Re: Quad filter Capacitor Reconstruction with Individual Internal Capacitors

    Post by tubed1 Wed Dec 29, 2021 5:57 pm

    Bravo, Bravo. Amazing how capacitor size has diminished in these last 60 (?) years. To be expected within this industry. Surprised we don't have a tube on a chip yet actually, or one that sounds pretty close.
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    New2Tubez


    Posts : 184
    Join date : 2018-03-20
    Location : NY

    Quad filter Capacitor Reconstruction with Individual Internal Capacitors Empty Re: Quad filter Capacitor Reconstruction with Individual Internal Capacitors

    Post by New2Tubez Thu Dec 30, 2021 5:58 pm

    tubed1 wrote:Bravo, Bravo.  Amazing how capacitor size has diminished in  these last 60 (?) years.  To be expected within this industry.  Surprised we don't have a tube on a chip yet actually, or one that sounds pretty close.

    Getting there:
    https://korgnutube.com/en/
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    jimafm


    Posts : 1
    Join date : 2012-07-11
    Age : 78
    Location : Chattanooga, TN

    Quad filter Capacitor Reconstruction with Individual Internal Capacitors Empty Re: Quad filter Capacitor Reconstruction with Individual Internal Capacitors

    Post by jimafm Sun Jan 02, 2022 12:00 am

    Well done! I go a slightly cleaner route by cutting out the bottom with a tiny Dremel router bit around the edge, pull all wires through a larger hole in the center and epoxying the bottom back in when done and checked.

    Once mounted, you can't tell there has been anything done.

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