I'm running a 6v 300ma adapter to run my Sangean ATS800 radio. I was
wondering if applying a couple of ferrite chocks like this to the DC power
cord would eliminate any humming noise created by the adapter.

http://www.piurl.com/p/22mW


The humm is not very loud, but it's noticeable. I know batteries are the
best solution, but in this case it's more convenient to use the adapter.

In message , homepc
writes
I'm running a 6v 300ma adapter to run my Sangean ATS800 radio. I was
wondering if applying a couple of ferrite chocks like this to the DC power
cord would eliminate any humming noise created by the adapter.

http://www.piurl.com/p/22mW


The humm is not very loud, but it's noticeable. I know batteries are the
best solution, but in this case it's more convenient to use the adapter.

Presumably you are referring to hum coming from the radio, and not
directly from the power adapter. However, either way, these chokes won't
make a scrap of difference.
--
Ian

"Ian Jackson" wrote in message
...
In message , homepc
writes
I'm running a 6v 300ma adapter to run my Sangean ATS800 radio. I was
wondering if applying a couple of ferrite chocks like this to the DC power
cord would eliminate any humming noise created by the adapter.

http://www.piurl.com/p/22mW


The humm is not very loud, but it's noticeable. I know batteries are the
best solution, but in this case it's more convenient to use the adapter.

Presumably you are referring to hum coming from the radio, and not
directly from the power adapter. However, either way, these chokes won't
make a scrap of difference.
--
Ian

So you are saying the RFI humm created by the wall wart is not being
directly transmitted by the power cord? I have a bit of excess power cable
bound up behind the radio and I notice if I move it around it creates a
variable humm. The fact that it is bound up there makes no difference, the
adapter interference was always apparent.

In message , homepc
writes

"Ian Jackson" wrote in message
...
In message , homepc
writes
I'm running a 6v 300ma adapter to run my Sangean ATS800 radio. I was
wondering if applying a couple of ferrite chocks like this to the DC power
cord would eliminate any humming noise created by the adapter.

http://www.piurl.com/p/22mW


The humm is not very loud, but it's noticeable. I know batteries are the
best solution, but in this case it's more convenient to use the adapter.

Presumably you are referring to hum coming from the radio, and not
directly from the power adapter. However, either way, these chokes won't
make a scrap of difference.
--
Ian

So you are saying the RFI humm created by the wall wart is not being
directly transmitted by the power cord? I have a bit of excess power cable
bound up behind the radio and I notice if I move it around it creates a
variable humm. The fact that it is bound up there makes no difference, the
adapter interference was always apparent.

OK, if it's a switchmode power supply emitting RF radiation, it might
help.
The only way is to try it.
--
Ian

Have you ever seen an adapter go BLOOEY! and ruin whatever it was
connected to? I have.
cuhulin

On Wed, 3 Feb 2010 16:21:54 -0600, "homepc"
wrote:

I'm running a 6v 300ma adapter to run my Sangean ATS800 radio. I was
wondering if applying a couple of ferrite chocks like this to the DC power
cord would eliminate any humming noise created by the adapter.

http://www.piurl.com/p/22mW


The humm is not very loud, but it's noticeable. I know batteries are the
best solution, but in this case it's more convenient to use the adapter.


I doubt it. The ferrite cores act as the core of a choke. If the AC
adapter used a switching supply, perhaps, but most wall warts are very
simple linear supplies (keeps the cost down0, so the hum is at 60Hz.
You are going to need a lot more inductance than a couple of ferrite
cores to keep it out.

On 2/4/10 13:30 , matt weber wrote:
On Wed, 3 Feb 2010 16:21:54 -0600,
wrote:

I'm running a 6v 300ma adapter to run my Sangean ATS800 radio. I was
wondering if applying a couple of ferrite chocks like this to the DC power
cord would eliminate any humming noise created by the adapter.

http://www.piurl.com/p/22mW


The humm is not very loud, but it's noticeable. I know batteries are the
best solution, but in this case it's more convenient to use the adapter.


I doubt it. The ferrite cores act as the core of a choke. If the AC
adapter used a switching supply, perhaps, but most wall warts are very
simple linear supplies (keeps the cost down0, so the hum is at 60Hz.
You are going to need a lot more inductance than a couple of ferrite
cores to keep it out.

That depends on whether the hum is simple ripple, or if it's an
artifact of rf mix products from local sources coming in on the DC
line from the adaptor. That's actually fairly common if there's a
local radio source. This type of hum may be distinguished from
simple ripple by the fact that it shows up at odd places across the
dial, and changes as the DC cord is moved. It shows up on stronger
stations than weaker, and generally isn't present during
interstation noise.

Usually, cores at the wall wart and cores at the DC connector
will, for all intents and purposes, eliminate this type of hum. In
sever cases, other types of filtration and a grounded wall wart will
be necessary.

On Feb 3, 4:29*pm, wrote:
Have you ever seen an adapter go BLOOEY! and ruin whatever it was
connected to? I have.
cuhulin

Ah, and what country did the bad wal-wart come from?

On 2/5/10 22:53 , wrote:
On Feb 3, 4:29 pm, wrote:
Have you ever seen an adapter go BLOOEY! and ruin whatever it was
connected to? I have.
cuhulin

Ah, and what country did the bad wal-wart come from?

In my own case, The Netherlands.

It was a little portable tv/radio combo with about a four something
inches tv screen size, ran on batteries/cig lighter plug/wal wart.I
think the wal wart zapped the tv/radio gadget.Maybe it caused an
internal short, or something.I don't like wall warts.
cuhulin