[Amps] Low ESR caps for amp power supplies

[KD7QAE]

John,

I don't believe the issue was with the HV Al EL caps used in our 
application but rather in the low ESR, LV parts used on the output of 
motherboard voltage regulators.  That said, it is good to be cautious.  
I would stick to brand names (Nichicon, United-Chemicon, Masushita, 
Rubicon) and only use new 105 deg C parts.  I buy from Digi Key and 
Mouser and get great service myself.  You do not need to stick to only 
Al EL caps though.  QROstuff (on ebay) is listing new old stock of 
energy storage pulse discharge rated caps from the old USSR.  These are 
ideal caps for HV PS filtering and you only need 1.  I think Rich has 
some 450V caps for sale right now adn I know he buys new and really good 
parts.

Tomm

W0UN -- John Brosnahan wrote:

>I am about to build a half-dozen power supplies for assorted
>amps for 160M and the VHF bands.  With a need for approximately
>60 electrolytic caps for the 6 power supplies it is imperative that
>I find some bargains.
>
>I am a bit concerned about surplus caps because of the materials
>problems that the Taiwan manufacturers had a few years ago --
>especially on the low-ESR aluminum electrolytics.  But I would
>buy surplus if I felt confident the caps were not on any list for
>problems.
>
>What I am looking for is something like 470 uF at 450 volts at
>105 deg C, rated for use in filtering (low ESR).   Has anyone
>already done the research to find the best value out there?
>Either for new or surplus caps?
>
>Actual capacitance is not critical,  if they are 220 uF caps, for
>instance, I will just parallel two strings.
>
>How about equalizing resistors, say 3 Watt ones.  Any bargains
>out there?
>
>Thanks  -- John  W0UN
>
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