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From: bmaraldo@watdcsu.UUCP
Newsgroups: sci.electronics
Subject: Re: Choosing Cap Size in Power Supply
Message-ID: <3691@watdcsu.waterloo.edu>
Date: Tue, 28-Jul-87 21:55:05 EDT
Article-I.D.: watdcsu.3691
Posted: Tue Jul 28 21:55:05 1987
Date-Received: Wed, 29-Jul-87 06:22:40 EDT
References: <5705@ut-ngp.UUCP> <1884@kitty.UUCP> <935@sdcc7.ucsd.EDU>
Reply-To: bmaraldo@watdcsu.waterloo.edu (Commander Brett Maraldo)
Organization: Unit 36 Research
Lines: 30



    The usual modification to an audio amplifier power supply is replacing
    the old caps with higher quality caps of the same capacitance or
    higher.  Also, the addition of a .47uF and 5uF polyproylene bypass cap
    helps to clean up the sound.  
    
    I have added as much as .25F to a power amplifier and notices an
    incredible improvement in the low end transient responce.  These
    modifications are of course audiophile related and my not make any
    sence in the real world.  As you know, the world of the audiophile
    operates under a different physics :-)

    I generally put as much capacitance on the dc rails as possible.  Under
    some operating circumstances, this may not be advised, but these
    unusual circumstances are unknown to me.  Also remeber to put a
    drainage resistor across the caps that'll drain them when the power
    shuts down.  On large supplies it is best to have a relay close which
    that places the resistor in the circuit.  I have welded a 3/8 inch
    drill bit to a quarter with my 40V .25F power supply.


					Brett L Maraldo


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