So I was thinking of building a linear psu for a new PC.

I came across this kit on ebay

https://www.ebay.com/itm/LPS200-Linear-Power-supply-kit-board-LPS-DC5V-9V-12V-15V-19V-24V-28V-L164-5/111964387845?hash=item1a1198fa05:m:m3fiLyO2CiBO8ZWg77rtjeQ

Anyone ever use something like this kit?  The Teradak products are really cool but pricey

Apart from its use as a PC linear supply, that is good value for a grunty supply anyway.

The thing to watch is reliability though. If one of the linear supplies goes down and the other voltages stay up, what happens? Or if one of the linear regulator series pass transistors go into second breakdown and shove raw rectified voltage up a supply line. A bit of failure mode thinking might be in order.

Edited July 4, 20188 yr by Craig Sawyers

Yeah, you can use it for a bunch of things.  The module itself seems to be in a bunch of psu's that power dacs, music servers, nas boxes.

In my case I'm going to use a mini stx board so the only power connection is 19Vdc.  The board then does the rest.  The trick for me is to find the right transformer.  I figure I need 25 Vac but not sure about VA, I'm thinking 150 VA or 200VA.  The complete psu's that you see are either toroids or r cores so I'd like to try and find both.  Antek has the toroid but can't find an r core in that size

How about https://www.yuan-jing.com/transformer/r-core/200VA/r-core-transformer-200va-input-ac-0-220v-output-ac-0-12v-x2-ac-0-24v-x2 . Ignore the low-current 12V, and parallel the 24V secondaries for 7.4A. No idea what the quality is like - Chinese of course, inevitably.

Shipping is quite expensive - about $64 (I put one in the basket and requested shipping cost to the UK) - but it does weigh 2.6kg (5.7lbs) so it is a hefty beast.

Just found from a google search. There must be other manufacturers out there.

Edited July 4, 20188 yr by Craig Sawyers

I did the same and found that the model number is common between a few vendors.  I'm in the US so I need 115V primary.  I found one of the same on ebay that's right around $100 us shipped from hong kong.  At triple the price I'm not sure R-Core is worth is unless someone else wants to chime in that it is 

A toroid will be just fine for what you are using it for. Audio applications sure, R-core is something to seriously consider, but for powering a PC I'd go toroid in a heartbeat. You're just after raw juice.

May want to check out Hd-plex 400W LPS ? 

For DIY, check out DIYinHk ?

They have upto 15V too! Ultra low noises

 

Edited July 5, 20188 yr by Whitigir

Yeah, I saw the HD-plex stuff.  I'll checkout the DIYinHK

I ordered that kit and a transformer.  Does anyone know where to get good quality 5.5 x 2.5 mm barrel plug ?

Doesn’t Mouser have anything?


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On 7/3/2018 at 10:12 PM, sbelyo said:

So I was thinking of building a linear psu for a new PC.

Very few, if any, components in a computer run off of 19V. There are doubtless myriad switchers throughout. What is the benefit of a linear supply here?

1 hour ago, Pars said:

Doesn’t Mouser have anything?


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Just found the S10 series from switchcraft.  Rated to 11 Amps

53 minutes ago, dsavitsk said:

Very few, if any, components in a computer run off of 19V. There are doubtless myriad switchers throughout. What is the benefit of a linear supply here?

I'm using a SFF (small form factor) mini STX board.  The power requirements are 19 V DC with wattage depending on what cpu is in use.  As you said it uses a myriad of switchers throughout to split that up into the required voltages.  It's really just to see if adding a linear supply at the source would make an audible difference.

On 7/24/2018 at 11:55 AM, Pars said:

Doesn’t Mouser have anything?


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Found this

https://www.mouser.com/ProductDetail/Switchcraft/760H?qs=%2fha2pyFaduhK01O5cZ%2fQBtF8MAu9dZTmuh89WSiPnHk%3d

good up to 8 amps +

Here's some scans of the part list and top and bottom of the board.

could this be given the GRLV treatment?

On 7/4/2018 at 4:39 AM, Craig Sawyers said:

Apart from its use as a PC linear supply, that is good value for a grunty supply anyway.

The thing to watch is reliability though. If one of the linear supplies goes down and the other voltages stay up, what happens? Or if one of the linear regulator series pass transistors go into second breakdown and shove raw rectified voltage up a supply line. A bit of failure mode thinking might be in order.

Both Craig and Kevin made a good point that I failed to see.  If any of the regulators let go it will send unwanted high voltage upstream.  Does anyone know if there are some crowbar circuit pcb's out there?  There's plenty of circuits I see on the web but not sure what to use.

this is already very similar to the grlv. missing the double noise inverting current source, but that is about it.

ic2 is an optional and higher quality alternate reference.

Edited November 1, 20187 yr by kevin gilmore

Very cool, thanks for looking at it.  I'm going to build it and run it without a crowbar circuit for now until I can figure out what circuit to use.  I asked for the schematic btw and they said no

Edited November 2, 20187 yr by sbelyo

 

ic2 is replacement for ic1, ref01,ref02,lt1021 etc

 

lps200.PDF

Edited November 2, 20187 yr by kevin gilmore

Thanks for the schematic!  When I look at the board JP1 seems to be in the mix.  Can you tell if I have to close JP1 to use U2?  

Looks like this is the part number I need for U2 LT1021DIN8-5#PBF

Edited November 2, 20187 yr by sbelyo

 you use either of the 2 references not both, and you have to adjust the resistor string for desired voltage

jp1 jumpers pin 8 of ic2 to ground.  definitely not for the lt1021 or ref01/02.

 

Edited November 2, 20187 yr by kevin gilmore

got it

Got my 24V assembled and running. I dont think it handles high current nicely. with 2A load @ 24v, I have about 1V drop at the output. 

 

On 11/2/2018 at 7:46 PM, kevin gilmore said:

 

ic2 is replacement for ic1, ref01,ref02,lt1021 etc

 

lps200.PDF

Does that mean you only require either u1/ic2, or they can both be fitted?

Edited July 29, 20196 yr by penmarker

I wound up ditching that kit I got from ebay since there was little in the way of protection if the regulators failed.  A few weeks ago Salas over at DIY audio came up with the L-Adapter board.  He tested failure in three different ways all of which ended with 0V on the output.  I got the board last week and will be ordering parts in a few weeks

https://www.diyaudio.com/forums/power-supplies/336685-adapter.html

I should have all the parts by the end of August