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Walwarts - linear supplies

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N2TK

Walwarts - linear supplies

I believe recently there was talk about noise from walwarts. Jameco
Reliapro offers a line of linear regulated walwarts. They are reasonable in
price and so far noise free.

They range from 2-24VDC with .2-1A output.

N2TK, Tony

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JT Croteau-3

Re: Walwarts - linear supplies

They are nice warts Tony. I have a 1A 12VAC Jameco Reliapro wallwart
for my beverage direction controller. It is extremely clean and noise
free.

73
N1ESE

On Mon, Nov 20, 2017 at 3:37 PM, N2TK, Tony <[hidden email]> wrote:

> I believe recently there was talk about noise from walwarts. Jameco
> Reliapro offers a line of linear regulated walwarts. They are reasonable in
> price and so far noise free.
>
> They range from 2-24VDC with .2-1A output.
>
> N2TK, Tony
>
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Joe Subich, W4TV-4

Re: Walwarts - linear supplies

In reply to this post by N2TK

All Electroncs (www.allelectronics.com) has analog wall warts of various
voltage/current capability depending on what is available in surplus at
any given time. One may not even need regulated voltage as many devices
contain internal regulators ...

They presently show 12 V @ 500 mA and 12.5V @ 410 mA units that appear
to be analog for less than $5.00 each in Q=1.

73,

... Joe, W4TV

On 11/20/2017 3:37 PM, N2TK, Tony wrote:

Jim Brown-10

Re: Walwarts - linear supplies

Older wall warts are linear. If you're smart enough to have saved them,
there's a good chance you won't have buy anything. Simply select one
with the matching voltage and rated for the needed current, cut the
cables to both old and new warts, splice the old wart to the connector
that mates with the unit you need to power.

Older warts are often available at second hand stores and flea markets.
$1 is the going rate. In general, linear warts are much heavier than
SMPS units, so that's a good first check. A better one is to plug it
into AC and hold a portable radio next to it tuned somewhere near 2 MHz
(like the top of the AM BC band). If you hear hash, it's a switcher. If
you don't., 99% chance that it's linear.

All of this is described in http://k9yc.com/KillingReceiveNoise.pdf

73, Jim K9YC

On 11/20/2017 1:17 PM, Joe Subich, W4TV wrote:
> All Electroncs (www.allelectronics.com) has analog wall warts of various
> voltage/current capability depending on what is available in surplus at
> any given time. One may not even need regulated voltage as many devices
> contain internal regulators ...

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N2TK

Re: Walwarts - linear supplies

Jim,
Good tip. I want to try that with some of my old walwarts
N2tK, Tony

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of Jim Brown
Sent: Monday, November 20, 2017 4:42 PM
To: [hidden email]
Subject: Re: [Elecraft] Walwarts - linear supplies

Older wall warts are linear. If you're smart enough to have saved them, there's a good chance you won't have buy anything. Simply select one with the matching voltage and rated for the needed current, cut the cables to both old and new warts, splice the old wart to the connector that mates with the unit you need to power.

Older warts are often available at second hand stores and flea markets.
$1 is the going rate. In general, linear warts are much heavier than SMPS units, so that's a good first check. A better one is to plug it into AC and hold a portable radio next to it tuned somewhere near 2 MHz (like the top of the AM BC band). If you hear hash, it's a switcher. If you don't., 99% chance that it's linear.

All of this is described in http://k9yc.com/KillingReceiveNoise.pdf

73, Jim K9YC

On 11/20/2017 1:17 PM, Joe Subich, W4TV wrote:
> All Electroncs (www.allelectronics.com) has analog wall warts of
> various voltage/current capability depending on what is available in
> surplus at any given time. One may not even need regulated voltage as
> many devices contain internal regulators ...

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Brian Hunt

Re: Walwarts - linear supplies

In reply to this post by Jim Brown-10

Be careful using the non-regulated linear wall warts. The open circuit voltage can be more than 16 VDC and could be harmful to gear not rated that high. Best to measure OC first!

73,
Brian, K0DTJ
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Jim Brown-10

Re: Walwarts - linear supplies

On 11/20/2017 5:50 PM, Brian Hunt wrote:
> Be careful using the non-regulated linear wall warts. The open circuit voltage can be more than 16 VDC and could be harmful to gear not rated that high.

Yes and no. The vast majority of linear wall warts are UN-regulated,
but the current drawn by the equipment being powered significantly
reduces the output voltage, usually to the rated value. That's how
linear, unregulated power supplies work. That's why it's good to match
both rated voltage and current. AND -- most equipment will tolerate
moderate over-voltage. The K3, for example, is rated for 15VDC max.

And, or course, not all gear runs on 12VDC -- lots of stuff runs on 5V,
7.5V, 9V, and 14V.

> Best to measure OC first!

Measuring OC is a good thing, and EXPECT to see 25-30% higher voltage
than rated. But what matters is the voltage under load. And that's why
my applications note recommends putting Power Poles on both the wart and
the connector to the equipment, then sticking a voltage monitor in line
with the equipment connected. You did read the link I posted, didn't
you? :)

73, Jim K9YC

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Larry (K8UT)

Re: Walwarts - linear supplies

In reply to this post by Joe Subich, W4TV-4

Two years ago, I embarked on a "wallwart-ectomy" in my shack, removing
all wall warts and replacing them with DC power cords that connected to
fused dc power strips, connected to a single shack linear supply. Band
decoder, PC speakers, SDR Rx, wavenode wattmeter... none of those items
have their own power source any more.

-larry (K8UT)

------ Original Message ------
From: "Joe Subich, W4TV" <[hidden email]>
To: [hidden email]
Sent: 2017-11-20 16:17:02
Subject: Re: [Elecraft] Walwarts - linear supplies

>
>All Electroncs (www.allelectronics.com) has analog wall warts of
>various
>voltage/current capability depending on what is available in surplus at
>any given time. One may not even need regulated voltage as many
>devices
>contain internal regulators ...
>
>They presently show 12 V @ 500 mA and 12.5V @ 410 mA units that appear
>to be analog for less than $5.00 each in Q=1.
>
>73,
>
> ... Joe, W4TV
>
>
>On 11/20/2017 3:37 PM, N2TK, Tony wrote:
>>I believe recently there was talk about noise from walwarts. Jameco
>>Reliapro offers a line of linear regulated walwarts. They are
>>reasonable in
>>price and so far noise free.
>>
>>They range from 2-24VDC with .2-1A output.
>>
>>N2TK, Tony
>>
>>______________________________________________________________
>>Elecraft mailing list
>>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>Help: http://mailman.qth.net/mmfaq.htm
>>Post: mailto:[hidden email]
>>
>>This list hosted by: http://www.qsl.net
>>Please help support this email list: http://www.qsl.net/donate.html
>>Message delivered to [hidden email]
>>
>______________________________________________________________
>Elecraft mailing list
>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:[hidden email]
>
>This list hosted by: http://www.qsl.net
>Please help support this email list: http://www.qsl.net/donate.html
>Message delivered to [hidden email]

Vic Rosenthal

Re: Walwarts - linear supplies

In reply to this post by Jim Brown-10

I've added regulators and (when needed) rectifiers to wallwarts. I just
put the components on a piece of perfboard, cut the wire, hook it up and
tape the board to the wart. Presto, a regulated linear wallwart.

73,
Victor, 4X6GP
Rehovot, Israel
Formerly K2VCO
http://www.qsl.net/k2vco/
On 21 Nov 2017 10:43, Jim Brown wrote:

> On 11/20/2017 5:50 PM, Brian Hunt wrote:
>> Be careful using the non-regulated linear wall warts. The open circuit
>> voltage can be more than 16 VDC and could be harmful to gear not rated
>> that high.
>
> Yes and no. The vast majority of linear wall warts are UN-regulated,
> but the current drawn by the equipment being powered significantly
> reduces the output voltage, usually to the rated value. That's how
> linear, unregulated power supplies work. That's why it's good to match
> both rated voltage and current. AND -- most equipment will tolerate
> moderate over-voltage. The K3, for example, is rated for 15VDC max.
>
> And, or course, not all gear runs on 12VDC -- lots of stuff runs on 5V,
> 7.5V, 9V, and 14V.
>
>> Best to measure OC first!
>
> Measuring OC is a good thing, and EXPECT to see 25-30% higher voltage
> than rated. But what matters is the voltage under load. And that's why
> my applications note recommends putting Power Poles on both the wart and
> the connector to the equipment, then sticking a voltage monitor in line
> with the equipment connected. You did read the link I posted, didn't
> you? :)
>
> 73, Jim K9YC