[Milsurplus] trany to tube transplant

[WA5CAB at cs.com]

I know the guy who did the work - supplied him with some parts, in fact, 
including the first set of 7-pin plugs.  I'm not certain why he bothered with the 
BC-348 and I didn't discuss it with him.  But the 1st requirement for the 
original work with the BC-611's was to do nothing that couldn't be easily undone 
leaving the radio back as original.  Preference was to be totally plug-n-play 
(aside from alignment, which the radio probably needed anyway).  2nd 
requirement was it had to work as well as the original but not necessarily better.  And 
final requirement was to operate from readily available (and likely to remain 
so) batteries.  The project was thus driven by the non-availability of the 
original batteries and the relatively expensive other alternatives.


> >http://grc9.wildlandradios.com/ 
> >He has solid state GRC, BC-611 and the BC-348. Don't get me wrong, I am
> >not saying it ant so but it all looks deceptively simple. I do not know
> >myself but have to wonder why if its that simple why manufactures in the
> >seventies like WJ had to use so many FET and transistors when this guy
> >dose it all with a handful, maybe the most modern FET are way superior
> >to the seventies and eighties designs and have great dynamic range?
> >Ray Fantini KA3EKH
> 
> Now, i have not looked at this guy's website for so long - thanks for 
> reminding me of it - but in his case it IS almost deceptively simple -
> as i recall he used exclusively triode-type transistors - JFETs - and
> not MOSFETS, which have a higher output resistance and less loading
> of tuned circuits. So my objection is that his M.O. is just a little too
> hands-on and simplistic.
> If you do go to a lower voltage supply it's not too difficult to convert
> to solid state, it seems. If you want to produce a "Tubester" type device
> that plays from the original HV, it will be a little more complex. The
> original Tubesters used an FET plus a bipolar (or two) to replace the
> vacuum tube.  -Hue Miller

Robert Downs - Houston
<http://www.wa5cab.com> (Web Store)
MVPA 9480
<wa5cab at cs.com> (Primary email)
<wa5cab at comcast.net> (Backup email)
   
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