[Amps] Dynamic regulation in PS

[Jim Thomson]

Date: Sat, 21 Apr 2012 14:10:19 -0700
From: Scott Townley <nx7u at nx7u.net>
Subject: [Amps] Dynamic regulation in PS

Re: the discussion on choke-input power supply filtering.
What is considered the target value for PS dynamic regulation for SSB?

-- 
Scott Townley
http://www.nx7u.net

##  1st,  your REAL no load  B+  is what you have when you hit the PTT, and
No drive is applied... IE: just drawing idle current.    That idle current alone will
drop it down a bunch, depending on plate xfmr used, etc.   You have to idle 1st,
before you can even apply drive. 

##  after that, you don’t want to see it drop at all, or very little on an average reading
typ HV meter.   If its XXX volts  when sucking idle current, and no drive applied, and then
when you talk on ssb, it drops 10 %...  IE:  now 90%  of the voltage on idle, Id say its 
not very good.   You need big wire from main panel to the amp to minimize the v drop
in the 240 vac line alone.   Its one big loop, so if you have say 30 ft of wire to the main panel,
that’s a 60 foot loop.   Since I have several amps and load sof other stuff that needs power, 
I opted to just install a 100 A sub panel on the other  side of the wall of the hamshack.    Then real
short runs of 10 ga wire to each of the table top amps.   3 ga wire is used from 100A sub panel,
back to the main 200A  panel.  

##  12 ga wire is way too small for most purposes, esp with typ lengths  required to get from the 
shack to the main 200A  panel.  6-8-10 ga  will work a lot better.  You can also just install a small,say
60-70 A  sub pnale in the shack, or close to it, then feed it with 6 ga wire.  Then short runs of 10-12 ga
to run all the ham gear and 10 ga for the amp.   Most ham shacks will only come with the usual 1-2 x 
duplex 120 vac outlets, which will typ be shared with lights and other stuff...all  on one 15A  breaker, fed with the
usual 12 ga  wire.  

##  with scopes, several xcvrs, extra power supplies, at least on hf amp, clocks , misc ham gear, 12 vdc supplies,
lights, 1000-1500 watt electric base board space heater, etc, etc, you may as well do it right.  
Instead of a separate line for the amp, you may as well just install a bigger line into the shack, and use it to 
feed a sub box...then distribute from there.   I use those bigger outlets you see, that are in the slightly 
bigger metal box.  They contain 2 x pairs of duplex outlets.   4 x 120 vac outlets in total.  I installed aprx
3-4 of those boxes on the back end of my desk.   Then one 15A  breaker per quad outlet.   Then  u have
enough juice to run anything you want. 

##  If  after all that, your dynamic regulation on ssb is still lousy, its time for a bigger filter cap, and or a
bigger plate xfmr.   Other than dropping a tiny bit when on idle, mine doesn’t move more than a needle width on
ssb, when drive applied, talking on ssb, with loads of processing.   If buying a new or used plate xfmr, size it
a little bigger.    It pays off asap.  Runs way cooler, and  dynamic regulation is much improved.  For your
typ 1.5 kw pep out ssb  amp, you want at least a 46 lb xfmr in there. 

later... Jim   VE7RF