On Fri, 2008-04-18 at 16:32 +0000, gardenyu wrote:
> Recently I'm purchasing some power supplies. What surprises me is that for some very similar power supplies, MFJ-4225MV
>  
> http://www.mfjenterprises.com/Product.php?productid=MFJ-4225MV
>  
> and VS35M
>  
> http://www.astroncorp.com/linear.shtml

As others have said, the MFJ is a switching power supply while the
Astron is a linear supply.  The closest Astron equivalent to the MFJ
above is probably the SS-25M.

Not being particularly versed in high current power supplies, I can't
really comment on the quality of either the MFJ nor the Astron products
from an engineering perspective.

I own three Astron supplies though and they have served me well.  An
RS-35M serves as the main supply for my radio equipment.  Previously I
used a 10-15 year old RS-20.  I use an SS-25M for traveling because the
switching power supply easily fits in my luggage.

The RS-20 is my current lab power supply.

There are a lot of mixed thoughts about both the Astron and MFJ
products.  Plenty of EE folks, who I suspect know what they are talking
about, say they are all poor designs.  At the same time, Astron supplies
have been the workhorse of amateur radio for quite some time.

Likewise, the "Mighty Fine Junk" products also come with mixed reviews.
I own a number of their products and I treat them like they are as
fragile as solar cells.  While they may not be the best built products
out there, in some cases, MFJ is the sole manufacturers of particular
products at a price level affordable to a hobbyist.  For anything
commercial, I'd stay away from their products all together.  They do
fill a hobbyist niche though.

-Jeff


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