[Amps] On Behalf of K4BOF

[Jim Thomson]

 No more
> yo-yoing bias either.  5 to 8.75 vdc bias is nothing short of lousy bias 
> regulation.

** That's no different than using diodes with no big electrolytic.....same 
result...the bias wanders a bit but really hurts nothing.

Carl

## Not quite.   7 x  1N5408's = 5.005 vdc    [ ,715vdc with   150 ma flowing through em on idle]
This will rise  by 12%  when 1.5A  flowing.    Then it's  5.60 vdc

##  8.75 / 5 =  1.75..or  a 75%  increase..which is a bunch.   It's probably no big deal though, the xcvr
is the limiting factor.   And yes, stick a big lytic across the string of diodes..and the resulting dynamic regulation
is superb, it then barely budges.  I like the string of diodes approach, since it's then real easy to change bias
Vdc  to anything you want..and do it on the fly.  That's good for experimentation purposes.  Like biasing it off
in class C  for FM.... or dropping the idle to just 20 ma for  CW use.... or  doing some IMD  vs   idle current 
tests.   Unless the xcvr is squeaky clean,  you would be amazed at how low you can lower the idle current
on a lot of GG triodes. 

##  BTW.. I have given up on the EBS  experiments.  [ electronic bias switching]  I can't get it to work any better
than before.  It works semi good on  PTT.... but if  using VOX SSB... the EBS saves so little power between
when you stop talking, and when the  vox drops out, it's a waste of effort.  It's of no benefit.  On CW, EBS is of no
benefit at all. Cranking up the bias V..and reducing the idle current to 10-20 ma works a helluva lot better. 

##  with some experimenting in the shop, 1A CCS  through a 1N5408 is not an issue.  Any more than that, then
the heat  builds up..fast.    With the 6A10...  2A  CCS  is max for that diode.   I also tried paralleling both 1N5408's
and also 6A10's..and can always get the current to divide  50-50...or extremely close to that. 

Later... Jim  VE7RF