|[AMRadio] Smoothing Choke & ART-13 supplies|
Foltarz at rocketmail.com
Thu May 4 13:51:03 EDT 2006
This discussion re the power supply filter has got me thinking.
This stuff has been done both ways.
I have built a power supply for my TBW using the swinging / smoothing
However, I also have in operation a 115 vac power supply for the ART-13.
It was made by the R.L. Drake Company - yup, the same one that is (was) in
Oddly enough, it is not that heavy. Perhaps 40 lbs.
When I got the unit the filament supply transformer was dead.
I replaced the (4) 866jr with silicon, all the electrolytics have been
replaced and I reworked the filament supply.
I removed the giant selenium rectifier in lieu of a full bridge rectifier
that was now mounted to the chassis.
I placed some large computer grade 35 volt cap across the output.
The filament transformer was replaced by a 19 volt 30 or so amp transformer
( 19 X 1.41 = 26.79 volts - close enough. )
The filter for both the hv supplies is a choke input followed by the
electrolytic. Presumably, it is pure smoothing.
The only thing I did to the ART-13 was remove autotune functionality by
desoldering a field winding.
Apparently, the fields are energized the entire time filament was supplied
making for a warm front panel and unnecessary load on the power supply.
By the way, I understand there is a mod to get around this "continuous field
on" situation besides my approach of desoldering the field connection.
If anyone has the dope on that pleas let me know.
--- Rick Brashear <rickbras at airmail.net> wrote:
> I appreciate your take on the power supply and agree for the most
> part. Even though this particular ART-13 will see little if any CW
> operation I would like the supply to be as stable and clean as
> reasonably possible. You are absolutely correct about the difference of
> availability of capacitors and chokes in today's world versus the days
> of W.W.II. I considered using more modern components and at one time
> even thought about an all solid state power supply. It would be much
> easier and cheaper to construct and less expensive to operate with less
> heat. However, the lure of the olden days kept calling me back to
> glowing tubes and swinging chokes. So, even though I agree that with
> modern technology applied I could have a cleaner, lighter and less
> expensive supply, I will likely stay with the old school thinking on
> this one. That is IF I can get the ripple to a low enough level so as
> not to cause problems on the transmitted signal.
> Thanks again for your advice and explanation, you make a very valid
> point and one which would serve my project well.
> Jim candela wrote:
> > Sorry but I am going to throw a wrench into this discussion. Those
> >swinging choke power supplies, although useful, have been out of favor for
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