Bob Miller ) writes:

There is absolutely no reason in the world to use a switching supply for
this.

The radio doesn't require much current, but the switching supply will
be far noisier than a linear supply unless it's really carefully filtered
and shielded.

Michael

Well, switching or linear, whatever. The point is, if the Sony AC
adaptor is so hard to find, and it's $100, a small, conventional power
supply would suffice.

A communications-quality switching supply would work (all ham
transceivers nowadays are paired up with such critters), or a standard
linear supply.

But the reason transceivers use switching supplies is because on
transmit a lot of power is needed.

That requirement isn't there for just a receiver.

But the "cost" of a switching supply in the application is the noise,
or the real cost of something carefully filtered and shielded, or
doing it yourself, to keep that noise to a minimum.

But that cost has no return, since the receiver requires so little
current that a linear supply will be small and not heavy, and
efficienty will not be an issue.

Michael