[Amps] Rectifier equilization?

[Jim Thomson]

Date: Sat, 14 Sep 2013 18:44:35 -0700
From: Jim W7RY <w7ry at centurytel.net>
To: amps at contesting.com
Subject: Re: [Amps] Rectifier equilization?

I completely agree that 6A10s are real overkill.

73
Jim W7RY

##  I need a one diode does everything....and the 6A10 fits the bill.
I use strings of em for bias for  GG amps.  In testing on the bench, the
5408 runs pretty warm-hot  with 1A  CCS  flowing through it.

## The 6A10  runs warm-hot with 2A CCS.   I use a rotary switch to 
change bias, tapping every third diode.   Then stick a huge lytic across the entire string
to get good regulation.   I also use the 6A10 as a safety diode
across meters..and also between  B-  and chassis, rvs connected.  In that
case I will parallel 2-3 diodes..in Each direction.   Then it any B+  to 
chassis mishaps, the B+ hv fuse blows, the glitch limits the current... and 
the paralleled 2-3 6A10  diodes handle the surge just fine.    A single
5408 can easily be stressed after a few hits. 

##  For FWB  power supply service, sure the 5408 is probably ample, considering
the diodes only have a 50%  duty cycle..when running rtty.   But if you are gonna 
buy diodes in bulk, like the typ 200-250 per box.... made by rectron....from mouser
etc,   why mess with buying both 5408 and  6A10 ??    IMO,  its  a one shot deal
buying diodes....so just buy 200-250 of the 6A10s..and be done with it. 

##  As a side note,  I think I measured  503 pf across all 250 x 6A10 diodes.... using my
B+K 875B  LCR meter.    They didn’t even vary by 1 pf.

##  1N4007 diodes are looney tunes.  5 years ago, they were as little as a penny each in bulk. 
Alpha used em in their megabuck 374A amp.   Useless as a safety diode..and useless for
bias in GG amps.  Marginal in a FWB  HV supply. 

##  6A10 diodes  work great in both single and 3 phase  HV supplys.   You can parallel
5408s if required..but why bother, just use a 6a10.   You can also parallel 6A10s  for
more current.... and the current will split almost 50-50 every time  if 2 used.... or
33-33-33  if  three used in parallel. 

##  BTW..  that single surge rating on any of these diodes is 8.3 msecs...that’s it.  

end of rant. 

Jim   VE7RF