"Michael A. Terrell" ) writes:
Unrevealed Source wrote:

In general, is it better to run a receiver off a good external DC power
supply, or using AC power and the built-in transformer? It would seem to me
that I might get less noise using an external DC power supply, but what is
the general concensus here? Thanks.

Jeff


What do you base this on? Why do you think an external supply is
better or quieter than the one designed for the radio?

The wording "external DC supply" versus "AC power" makes me think
that he thinks he's comparing apples and oranges. Unless he's
talking about running it off batteries, an "external DC supply" runs
off AC and is the same thing as "AC power".

Michael

Michael Black wrote:

The wording "external DC supply" versus "AC power" makes me think
that he thinks he's comparing apples and oranges. Unless he's
talking about running it off batteries, an "external DC supply" runs
off AC and is the same thing as "AC power".


Even then he could have more noise from batteries due to the internal
resistance of the battery causing poor regulation, and noise picked up
on the wires that connect the battery to the radio.

--
Former professional electron wrangler.

Michael A. Terrell
Central Florida

There should be some regulation in the radio itself on the DC input,
This doesn't have to be the case, but most radios provide a DC input
for use in mobile applications, and car voltages vary from a low if the
car is not running to a high if the battery is being charged. Even
worse would be spikes from a bad diode in the alternator. Generally a
device designed to work from auto power is designed to handle at least
16V. Many put the limit at 24V, which comes from some case where people
would put car batteries in series. Yeah, I know this sounds odd, but I
worked on a bid with Chrysler and they had a 24V upper limit on the
electronics at the time. The story I got was some people would jump
start cars with two batteries in series.

The DC input should be filtered a bit in the radio as well since auto
power isn't all that clean.