[Amps] Alpha PA-76A bleeder/equalizer resistors

[Jim Thomson]

Date: Thu, 10 Oct 2013 10:58:50 -0400
From: "Carl" <km1h at jeremy.mv.com>
To: "Jim Thomson" <jim.thom at telus.net>, <amps at contesting.com>
Subject: Re: [Amps] Alpha PA-76A bleeder/equalizer resistors

Jim, the tolerance is not that critical since there is plenty of voltage 
overhead and the original 5% carbons worked for about 35 years.

Standard 5% 3M MOX from Mouser or elsewhere is fine for another 35 years. 
All the ones Ive checked are within 2% anyway and modern replacement caps 
are listed at 20% but come in around 10% or less at the values used in most 
amps.

Carl
KM1H

##  I noticed that  Rich measures 560 uf   HV filter caps read aprx 19% on the low side  for
some reason.   I had a batch of GE caps that all read 1800-2300 uf.... but were stamped 
1600 uf..go figure.


##  some folks like to  operate caps almost at their max V rating.  Factor in caps that
vary a lot of uf between each other, and you might be cutting it close in some cases. 
In these HB HV supplies I build,  I never run the caps at more than 70-75% of their
max V rating, so plenty of  headroom. 

## Those .2% tolerance resistors cost dick, so I thought I would give em a try..and
bought 300 of em.  It brings the concept of  forced V drop across each cap to a whole new level..as
in they all read identical V drops..right down to 2 x decimal places.   All  300 resistors measured the 
same, identical  99,980 ohms.   I know its overkill,  but I sleep better at night. 

Jim  VE7RF