[Elecraft] Switching v. Linear Power Supplies

[Eddy Avila]

Rick, based on a review in QST (and price) I bought the mfj 4225 switching 
supply and not been disappointed (unique for mfj products!) -- I've powered 
eveything from QRp rigs to my power hungry Kenwood and ICOM hf rigs and the 
supply handles it all with regulation better than my linear supplies! Never 
heard any RF hash on any band and I really checked throughly when I first 
got the supply.

Quality (on the outside) appears good, but I'm still amazed mfj can make a 
good product that works as advertised....HI

73....ed


>From: Rick Lellinger <relellin@yahoo.com>

>Greetings,
>
>I've been working with electronics as a hobbyist for over twenty years and
>I've always powered my projects with linear power supplies.  I no longer
>have access to my heavy 30amp Astron supply and I'm considering an MFJ 
>13.8v
>25amp (#4225) switching supply (reduced weight and size). It will power 
>both
>my K2 and a VHF radio. However, I am concerned about RF hash from the unit
>as well as ripple. I noticed that the MJF supply has a ripple figure of 
>35mv
>while a comparable Astron linear supply has a mere 5mv of ripple. The
>voltage regulation is fine, which is good.
>
>1. Has anyone used the MFJ 4225 switching supply with good results, that is
>decent regulation and NO hash (Rx OR TX) ?
>
>2. Is 35mv of ripple too high? I know that the K2 and most good radios
>contain excellent voltage regulating circuitry and so this may not be an
>issue.
>
>Thanks
>
>Rick L


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