Switching vs Linear Power Supplies

[Jack]

I am moving my shack to a new location and was considering repacing my Astron 70M  (70 amps with meters)with something smaller.

I saw some small switching supplies that seemed to do what I wanted but they all have fans.  The last thing I want is more noise in my shack.

Anyway, is there any advantage to a switching power supply (with a fan) vs a linear supply (with no fan) other than the size and weight?

Jack, AE6GC
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[Joseph Reed-2]

Noise aside, I have two big honking linear power supplies and a switching supply of the same rating.  No difference except you don't risk a hernia when you move the switcher.

Some folks will say the linear is quieter.  But in an urban environment you can't tell the difference.  Noise is everywhere.

To answer your question directly - No.  They both do the same job.  But not all switchers are made equal.  Some are very noisy, others make a concious effort to minimize noise.  My Astron switcher is very quiet, and I have never noticed the fan as it is about 4 feet from the operating position.   Your mileage may vary depending on how close you place it.

Joe N9JR

----- Original Message ----
From: Jack Regan <[hidden email]>
To: [hidden email]
Sent: Wednesday, October 3, 2007 9:08:47 PM
Subject: [Elecraft] Switching vs Linear Power Supplies


I am moving my shack to a new location and was considering repacing my Astron 70M  (70 amps with meters)with something smaller.

I saw some small switching supplies that seemed to do what I wanted but they all have fans.  The last thing I want is more noise in my shack.

Anyway, is there any advantage to a switching power supply (with a fan) vs a linear supply (with no fan) other than the size and weight?

Jack, AE6GC
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[Clark B. Wierda]

Jack Regan wrote:
> I am moving my shack to a new location and was considering repacing my Astron 70M  (70 amps with meters)with something smaller.
>
> I saw some small switching supplies that seemed to do what I wanted but they all have fans.  The last thing I want is more noise in my shack.
>
> Anyway, is there any advantage to a switching power supply (with a fan) vs a linear supply (with no fan) other than the size and weight?
>
> Jack, AE6GC

Properly designed and manufactured, switching power supplies can be more
efficient ( 70-80 %) than linear power supplies (~50%).  For a given
load, they should use less power and run cooler.

The issue to be considered is the EMI produced by the switching power
supply.  Some are good and others aren't.  It depends on the model and
the installation.

As to the noise the fan makes, you might have to try it to see.  There
are some very quiet fans in use these days.  Are you going to have a
computer in the shack?  If so, its fan(s) is likely to be louder than
the one in the switching power supply.

73,
--
Clark B. Wierda
N8CBW
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[Jack]

Thanks to all who answered so quickly!
I have all the info I need to make a decision now!

Jack, AE6GC

PS.  I will probalbly sell the Astron 70M when I get  my new, light weight, small, quiet, switching power supply.

J
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[Brett gazdzinski-2]

 
One more thing that might come into play, some of the old
non switching power supplies were very robust, in that they
could take a lightning hit and laugh at it, while switching
supplies would fry. The big transformer protects things somewhat...

I have some fero resonant power supplies that are very simple,
transformer, rectifier, a few caps, that have been in service
for 20 years without failure.
Fero resonant supplies are very noisy though, and not in the RF way...

Brett
N2DTS

 


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