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Do I need to recap??

Discussion in 'Amps and Cabs [BG]' started by Vanagon, May 31, 2005.


  1. Vanagon

    Vanagon

    Nov 13, 2004
    My Traynor YBA-4 has always had a bit of a hum to it, that starts as soon as I power it up, it also seems to be slowly getting worse. I'm guessing its time for some new filter caps (has originals), but just wanted to get some verification before I tear into it. The amp is sitting right next to a SUNN300T and a Blues Jr. and both those are nearly silent when I power them up, so I don't think it's anything from the power or room. I also just bought an old Kay transistor amp that has a very similar hum, but even louder which is what got me thinking about this. So I'd say I'm 86.7% sure I need to recap, but I wanted to let those with a bit more wisdom on the subject verify it for me. Thanks.
     
  2. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    If the amp is over 20 years old recap, and if you can go with higher uf values (caps are smaller today than they used to be for the same values) do so.
     
  3. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    Very likely you'll need the recap.
     
  4. And be sure the new caps have the same or higher voltage rating, don't want a cap exploding!!!

    IIRC, Mouser has them up to 500VDC, cheap and fast delivery and small orders are fine.
     
  5. Vanagon

    Vanagon

    Nov 13, 2004
    Thanks for the responses guys. Guess it's time to break out the soldering iron. Just wondering what the benefit of going with a higher value is? I believe there is 40uf 450volt caps in there now; how much should i bumb them up? 80uf? 100uf?
     
  6. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The more capacitance you add the better filtering you get, so go as high as you can that will fit the available space without devaluing the voltage.
     
  7. Kael

    Kael Supporting Member

    Dec 26, 2004
    Oklahoma City
    No you don't need to recap, however I will offer no evidence or argument to that effect. By my reckoning that should place you at 86.65% sure. ;)