re[Elecraft] .: Switching Supplies

[ab2tc]

Hello all,

I am using the MFJ-4125 25A switcher with my K3. I have no RF hash or
birdies from the power supply at all. I find it unbelievable that popular
and supposedly quality power supplies like the Astron would leave exposed
transistor cases at elevated voltage above ground. The MFJ fan, which is
always running, isn't whisper quiet, but not really noisy either. This
switcher faired very well in the ARRL review a few years back, in fact it
was one of the most quiet ones tested.

Knut - AB2TC



Mike Scott-7 wrote:
> 
>>I also have an Astron RS35 and RS50 linear 
> supplies.  Sometimes the magnetic hum from them drives me crazy.  The
> little
> 
> cork pads Astron puts in them to alleviate this
> does not help much. I keep them under the closed console on the floor.
>                       Mike  WA8EBM
> ----- Original Message -----
> 
> I have my RS 35M on the floor also. I shorted it out once momentarily an
> exciting moment. The problem is that the transistor cases that you see
> sticking out of the back on the heat shield are at V+ level. If something
> like a ground braid (this was my case) touches the transistors or the 12V
> output terminal you have a short. 
> 
> I ended up finding a cardboard box and cut the top and front off and most
> of
> the sides off. What is left is a cardboard "back shield" with lots of
> ventilation to prevent accidental connections to the wire maze I have down
> there on the floor.
> 
> Mike Scott - AE6WA
> Tarzana, CA (DM04 / near LA)
> K3-100 #508/ KX1  #1311
> 
> 
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