Beware the wall rat

[ef37a]

Or in this case the line lump. For many years I have butchered the LT leads on these things when I needed certain volts/amps but the plug was the wrong size or indeed wanted to splice it directly into a circuit.

I always found that the cable was screened, I assumed to contain much of the residual 'hash' that such supplies put out. Today I stripped one back to find a single red and single black wire. No screen.

The supply was a R.S brand (NOT to be confused with RS Components) and rated at 22V 1A. So, if any of you find an odd noise in your systems, especially one that has come about after purchasing a bit of rat powered kit, an unscreened power lead could be the cause?

Dave. (that's R dot S)

[resistorman]

In my repurposing and chopping of rats, lumps and warts I’ve rarely seen one that WAS screened.

[ef37a]

In my repurposing and chopping of rats, lumps and warts I’ve rarely seen one that WAS screened.

I don't mean the cheaper 5V things you get for powering phones and small devices like S/PDIF switches. I mean 12V at an amp and up.

Dave.

[resistorman]

In my repurposing and chopping of rats, lumps and warts I’ve rarely seen one that WAS screened.

I don't mean the cheaper 5V things you get for powering phones and small devices like S/PDIF switches. I mean 12V at an amp and up.

Dave.

Me too And since almost none of them are actually grounded, I don’t know what a shield would do?

[ef37a]

In my repurposing and chopping of rats, lumps and warts I’ve rarely seen one that WAS screened.

I don't mean the cheaper 5V things you get for powering phones and small devices like S/PDIF switches. I mean 12V at an amp and up.

Dave.

Me too And since almost none of them are actually grounded, I don’t know what a shield would do?

Thought of that too, they would find earth at their destination much of the time e.g. an AI via either USB or audio connections.

Of course, gear is increasingly becoming earth free...

Dave

[Hugh Robjohns]

The screening suggestion doesn't hold much water for the reasons above. I suspect they use coax cable just because it's easier to terminate with a coaxial DC plug.

[ef37a]

The screening suggestion doesn't hold much water for the reasons above. I suspect they use coax cable just because it's easier to terminate with a coaxial DC plug.

This two wire PSU HAD a co ax plug! Jeez! I can do without all this negativity...Jus' sayin!

Dave.

[Folderol]

The screening suggestion doesn't hold much water for the reasons above. I suspect they use coax cable just because it's easier to terminate with a coaxial DC plug.

This two wire PSU HAD a co ax plug! Jeez! I can do without all this negativity...Jus' sayin!

Dave.

Exactly. I remember those coax DC leads - much easier to secure with a simple gland. Oh, and (of course) the figure of eight cables STILL feed a coax plug.

And another thing. I'm pretty sure that in their original transformer and fat caps form, in the UK at least, they were not floating, but earthed.

[ef37a]

The screening suggestion doesn't hold much water for the reasons above. I suspect they use coax cable just because it's easier to terminate with a coaxial DC plug.

This two wire PSU HAD a co ax plug! Jeez! I can do without all this negativity...Jus' sayin!

Dave.

Exactly. I remember those coax DC leads - much easier to secure with a simple gland. Oh, and (of course) the figure of eight cables STILL feed a coax plug.

And another thing. I'm pretty sure that in their original transformer and fat caps form, in the UK at least, they were not floating, but earthed.

THANK you Will! I don't even mean the fig 8 jobs. The one I stripped had a round, quite stiff cable...THAT is why I was surprised at the lack of a screen.
(I know I am getting on but I'm not quite THAT daft...yet.)

Dave.