Replacement Caps for AMP

drselect
drselect Posts: 664
edited January 2011 in DIY, Mods & Tweaks
Was needing some help with suggestions for replacing the 270uf/50V power transformer filter caps with 270uf/100V caps on my tube amp. I will admit that I know very little about the types of caps available and were to get them from. I have done some searching on the web but I am somewhat overwhelmed by the number of different caps available and what types are best in which application.
Thanks.
Post edited by drselect on
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  • FTGV
    FTGV Posts: 3,649
    edited January 2011
    Panasonics FC series from Digi Key would be a good choice but they may require you to purchase more than two.Otherwise considering were it's used any good electrolytic with should be fine.As well as your value and voltage rating look for a temp rating of 105 degrees vs 85 degrees as they will havve a longer usable lifespan.
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  • FTGV
    FTGV Posts: 3,649
    edited January 2011
    Heres an option in case Digi Key requires a minimum order.
    http://www.partsconnexion.com/product17694.html They are 330uf/100v but since they are used in the power supply a little more capacitance isn't a bad thing.
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  • F1nut
    F1nut Posts: 50,654
    edited January 2011
    Neither Digi-Key or Mouser require a minimum order. The Panasonic's are an excellent choice and I agree, get the 105 degree versions.

    edit:
    Just looked at your picture. It's not very clear, but I don't see any leaking or evidence that they are ready to blow, so why do you want to replace them?
    Political Correctness'.........defined

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  • zingo
    zingo Posts: 11,258
    edited January 2011
    Bennic 280uf Electrolytic

    M280.jpg

    I just used these in my Tripath amp, and they made a noticeable improvement.
    Jake
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  • drselect
    drselect Posts: 664
    edited January 2011
    F1nut wrote: »
    edit:
    Just looked at your picture. It's not very clear, but I don't see any leaking or evidence that they are ready to blow, so why do you want to replace them?

    F1nut, I am planning some mods/repairs to the amp and a note posted by the manufacture on another forum states:
    ""For DiY: change the G1 minus voltage electrolytic capacitors to higher voltage types. (the rating from PT is 35V AC , the cap is 270uf/50V. should use 100V capacitor)""

    I am still on a steep learning curve and really don't know why they would recommend this other then possible safety reasons but since I was going to have the guts out of it I figured I try to do things all at once.

    I also was considering new caps in the ""coupling position" which I think are a 0.1uf/400v but not sure I wanted to replace those yet since I think they are more in the "sound" path and I am not sure I want to really mess with that yet or if there is room for them.
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  • drselect
    drselect Posts: 664
    edited January 2011
    zingo wrote: »
    Bennic 280uf Electrolytic

    M280.jpg

    I just used these in my Tripath amp, and they made a noticeable improvement.

    Jake, I saw the thread discussing your instillation of these and was concerned about the size of them. I did find the dimension for the cap you linked and think it could possibly fit but I noticed that it was a axial cap instead of a radial cap which may also add to the make it fit issue.

    Another thing of I noticed but was not sure about is I see that that is a bipolar cap and the scheme is calling for a polarized cap. Does "bipolar" and "polarized mean the same thing?
    Thanks
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  • zingo
    zingo Posts: 11,258
    edited January 2011
    Bipolar and polarized are opposite designs, and usually only electrolytic caps have a polarization. I have swapped polarized radial caps many times with bipolar axial caps, and the change was fine other than the physical lay out and making things fit. Since polarized caps only have to operate one direction, they can be much smaller for a given value, making them the choice for many installers, even if there are better aural choices.
    Jake
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  • drselect
    drselect Posts: 664
    edited January 2011
    zingo wrote: »
    Bipolar and polarized are opposite designs, and usually only electrolytic caps have a polarization. I have swapped polarized radial caps many times with bipolar axial caps, and the change was fine other than the physical lay out and making things fit. Since polarized caps only have to operate one direction, they can be much smaller for a given value, making them the choice for many installers, even if there are better aural choices.

    Other than cost is there a specific reason that a polarized cap would need to be used in place of a bipolar cap?

    Also in top left section of the scheme I attached above there is a 22 uf and a 68 uf polarized caps shown, do you happen to know what those are for and would there be any advantages to replacing those?
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  • zingo
    zingo Posts: 11,258
    edited January 2011
    Polarized electrolytic caps are smaller and cheaper than bipolar or non-electrolytic caps; just for the same reason your car has a cheap, restrictive muffler rather than a high performance, high flow unit.

    The 22uf and 68uf caps are only to ground and would not be an improvement in IMO. The coupling caps would be your best upgrade; .1uf and .47uf caps.
    Jake
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