Battery or linear power supply, 18 volt - 300 milliamperes? Build it DIY or Pro

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undertow

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Not sure this is the best circle to post this so here it goes...

I am seeking a source to either build or just buy a reasonable priced 18 v - 300 milliamperes capable DC power supply to replace a generic wall wart.

I have read good and bad about battery based supplies, but I assume they are a little cheaper, and more compact overall vs. a good linear supply.

It will be a dedicated supply in other words feed the DC power output via an umbilical cord so it needs to be in its own chassis with AC IEC input etc... it will not be built into something, but it's own standalone unit.

I did find something from Red Wine Audio that seems to be a type of battery unit, and configurable to 18v, but still want more options, and possibly better pricing.

Thanks

sfox7076

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I imagine the battery supply would be bigger than an LPS if you are keeping the unit on for a while.  You will need a battery big enough to keep the unit going. That is usually big. 

randytsuch

What are you going to power with this?  Is it exactly 18V, or can it be higher or lower?  (batteries are usually not at the voltage on the label)

For DIY, are you looking for a kit, or can you build it yourself?

I'm in the middle of building a power supply for a headphone amp, going to try using lifepo4 batteries.  I need + and - 18vdc, plan to wire 5 batteries in series for each voltage.  With batteries, you also need a charger.

How long do you want to run between charges?

For a linear PS, there are lots of chinese voltage regs on ebay you could use.  I think some of them just need a transformer, and they do the rest. 

Finally, there are liability concerns for DIY Power Supplies, I wouldn't do it if I didn't know what I was doing.

Seems like this might be better in the Lab forum too, at least for DIY.

I've also seen other options for linear PS's you can buy, but I dont remember the names of the places.

Randy


WGH

Without hesitation I would jump on the Acopean B18G30 Linear Regulated power supply for $50 that is on eBay. The Acopean power supplies are my go to brand when replacing wall warts, they are commercial grade and built to last forever.

Output volts:18
Output current: 0.3 amps
Regulation - Load: 0.05%
Regulation - Line: 0.05%
Ripple mV RMS: 1
http://www.acopian.com/store/9-%287%29.aspx?min=18&max=25

Wayne

undertow

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It is for powering a phono amp, yes it is 18v. Actually the phono stage is made by Clearaudio and I just realized they make a battery power supply for it, but it's 900 bucks I rather find something else for that money. I almost prefer working toward a linear power supply all together at this point. See link

http://www.needledoctor.com/Clearaudio-Accu-Battery-Power-Supply?category=35447
« Last Edit: 5 Oct 2015, 12:48 am by undertow »

randytsuch

FYI, 18V is not always 18V.  Strange, right? 

When I measure walwarts, they rarely put out the voltage that is printed on them, usually more.  My 115V is a little high, more like 120V out of the wall, so that may be why it's high for me.

You can measure the walwart, and see what it puts out.  Also, if the walwart is rated for 300 ma, your phono stage almost certainly uses less, but I can't tell you how much less.

Your stage may (I would say it's likely) have another regulator inside, so it may not need exactly 18V.

For a phono stage, it's probably worthwhile to get a very low noise supply.

good luck
Randy

undertow

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Okay Core Audio Technology builds Linear power supplies which are pretty pricey, but they gave me a great deal on this one due to having very low power requirements, and they had some left over 18 volt boards due to their current moving sale on the site.

Thanks guys.