[AMPS] Plate transformer, chimneys

[notawc@juno.com]

On Sun, 02 May 1999 10:03:47 -0700 Vic Rosenthal <rakefet@rakefet.com>
writes:
> 
> I've got just about all of the parts for my 2 x 3-500z amplifier 
> except the
> plate transformer.  I haven't been able to find one of reasonable 
> size and
> weight inexpensively, so I'm thinking about buying one from Dahl.  


Inexpensive and Dahl do not work in the same context.


> My question
> is:  should I get a transformer for a doubler or full-wave bridge 
> circuit? 


A doubler in SSB/CW use offers a significant advantage over a FWB. Been
explained here too many times to go into that again.

 I
> was planning to use a doubler and one of the SB220-replacement type 
> of
> transformers, but I realized that if I'm actually going to buy a new 
> one, I can
> get whatever I want.  I already have 8 240uf 450v electolytics for 
> the filter; I
> can use them in either configuration.


Good values as long as they can handle the ripple current.  Cheap bargain
caps are a potential disaster.


> 
> I want to run the amp at 3000v.  Would a bridge circuit provide a 
> stiffer plate
> supply?

Not at those cap values.  For intermittent service such as SSB/CW the
doubler can actually be more efficient since it uses a larger guage
secondary wire; assuming equal KVA ratings of course. There is a lot to
be said for using capacitor storage in some applications.



> 
> Also, I need a pair of 3-500z chimneys.  Somebody had a pair for 
> sale, but I
> can't find his message. Anyone?

Ameritron uses a cut down version but they work and are cheap. BTW,
unless you are pushing for lottsa RF out a chimney is not a
requirement....good airflow is. Buy one of Harbach's high volume SB-220
fans.


> 
> 73,
> Vic, K2VCO
> Fresno CA
> 
> --
> FAQ on WWW:               http://www.contesting.com/ampfaq.html
> Submissions:              amps@contesting.com
> Administrative requests:  amps-REQUEST@contesting.com
> Problems:                 owner-amps@contesting.com
> Search:                   http://www.contesting.com/km9p/search.htm
> 
> 

___________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com/getjuno.html
or call Juno at (800) 654-JUNO [654-5866]

--
FAQ on WWW:               http://www.contesting.com/ampfaq.html
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm