> I am becoming more and more disgusted with the lack of
> technical
> knowledge QST authors. A fine example is the article
> about reviving old
> linear amplifiers in the most recent QST. There is a
> schematic and
> description of a half-wave voltage doubler which is
> claimed to have been
> used on many older amplifiers. But, everyone that I have
> seen uses
> full-wave voltage doublers. The only half-wave voltage
> doublers I have seen
> are usually in TV sets and other tube equipment that
> operated off the power
> line with out a transformer.
The same author in a solid stat amp article made a series of
mistakes, including using an ALS600 power transformer
without the filter choke. The ALS600 is designed to use a
filter choke. Use without the choke would result in about
80-100 volts on the 50 volt FET's. That's a BIG error.
Also Motorola's board has some design issues, so it isn't
just QST authors who could use improvement.
The only thing in the article I saw sticking out was he
recommended using small 470k resistors across the diodes.
Bad idea.
The rest of the errors are what I would call small
73 Tom
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