Experience with brick PSU for ATX board?

silvervarg · Post by **silvervarg** » Fri Aug 13, 2004 1:22 am

I searched the PSU forum carefully, but could find very little on what experience users have with brick PSUs at all.
I know some use them to power VIA C3 mini-itx boxes, and some of the kits are made explicitly to power these boxes.
What does interest me is how they work to run normal ATX computers (mATX or ATX). It should work fine to run them with any low power system, but I lack any practical experience.

So, everyone that is running an mATX or ATX system with a brick PSU please post your knowledge here. Also post what PSU you are using, what hardware you are running on that PSU and if you know how many watts the PSU has.

Perhaps MikeC could do his PSU test on a few brick PSU to see what they could do.

I guess most ATX systems today require the square 4-pin P4 connector, so only DC/DC boards with this connector works, right?

josti · Post by **josti** » Mon Aug 16, 2004 12:51 pm

I've got an external psu, which powers my p4 system. i bought this psu on ebay last september and never had any problem. it's divided in an external ac/dc-converter and an internal converter which provides the atx-voltages. it even has the 4-pin connector for p4 systems.

here my system:
- Albatron PX845GEV Pro mainboard (normal atx-board with graphic onboard). it allows to undervolt to 1.1v.
- P4 1.6 GHz (clocked at 2 Ghz and 1.225v, needs 20-25w)
- 512 MB PC2700-Ram
- 20 gb 2.5''-hd from toshiba (can't be heard), and a 80 gb samsung (most time sleeping, needs 5w when running)
- DVD burner
- Technotrend DVB-S card (consumes ~7w)
- Wlan-card

under full load (with 80gb hd and burner off) the system consumes about 62 watt (normal psu consumes almost 80 watt with the same system), and the best thing is that you can't hear it. the external brick has a temperature of 45-50Â°C (~25Â° over room temp).
I could clock the p4 higher but i don't like the psu getting any hotter.

the system is always on and crunshes for http://www.climateprediction.net

if you want to use such a psu with a modern cpu (p4 northwood, athlon64) and want to use it under full load, it would be good if the motherboard allows to undervolt the cpu, i think.
and of course the graphics card shouldn't need to much power.

on the following link the psu was offered (sorry it's in german, but i may help):
http://cgi.ebay.de/ws/eBayISAPI.dll?Vie ... 3486337720

somebody · Post by **somebody** » Wed Aug 25, 2004 12:03 pm

Does anyone know where to purchase a brick PSU that provides more than 110W?

msde · Post by **msde** » Wed Aug 25, 2004 3:55 pm

http://www.mini-box.com/pw-200.htm

200W, but I'm not sure which brick you'd use.

somebody · Post by **somebody** » Wed Aug 25, 2004 6:05 pm

I asked about "where to purchase a brick PSU".

silvervarg · Post by **silvervarg** » Wed Aug 25, 2004 11:17 pm

Does anyone know where to purchase a brick PSU that provides more than 110W?

dc2dc.com has a 120W. Available both as only brick and as full kit.

mini-itx.com has a 150W, but it has a fan in the brick part.
The biggest fanless they have is 110W.

The problem with higher power is the heat that is generated in the PSU.
Either you make a much bigger brick part so it can dissipate heat better or they have to increase the efficiency a lot, and that would probably make the brick very expensive.

msde · Post by **msde** » Thu Aug 26, 2004 9:00 am

somebody wrote:I asked about "where to purchase a brick PSU".

I replied with a link to a brick PSU. /shrug

If your complaint is that you couldn't add it to a shopping cart, then I apologize, but you could have just clicked on the words "buy online" on the page I originally linked.

http://store.mini-box.com/ituner/pw1220atxmip.html

hvengel · Post by **hvengel** » Thu Aug 26, 2004 10:49 am

"Brick" power supplies of various sizes are used for powering ham radios. Many of these are fanless and all are very high quality. These can be had as large as 57 amps (786 watts at 13.8 volts) continous. Most of the larger units have fans but many of the small and medium sized ones do not. They are fairly expensive for thier power output compared to normal PC PSUs. One that will handle 200 watts should be around $150 to $250 new depending on features and these are available from a number of vendors.

For example the Astron RS-35A is rated at 25 amps continous and 35 @ 50% duty cycle (5 min. @ 35 amps 5 min. off). It has no fan and the voltage can be internaly adjusted from 11v to 15v. It comes from the factory setup for 13.8 volts (same as a 12 volt battery). Output voltage is regulated to +- 0.05 volts and max ripple is 5mv at all loads. This is a big transformer based (not switching) power supply that measures 5x11x11 inches and has a shipping weight of 27 pounds. I have seen web sites that price this unit at $149.95 + shipping (some offer free shipping). Not cheap but it would easily handle 200 watts.

Another option is the RS-20A which is rated at 16 amps contiunous (220 watts @ 13.8v) 20 @ 50% duty cycle (276 watts). This unit is 5x9x10.5 inches with a shipping weight of 18 pounds and a cost of $97.95 + shipping.

If you live in a larger city you should be able to find a local store that specializes in ham radio gear. For example in my area there are three HRO discount ham radio stores with in a one hour drive of where I live. The folks there are very friendly and very well versed in electronics. Everyone that works there is a ham and has taken tests in radio therory (electronics) to get thier license. I am sure that they would be willing to spend some time talking to you about what power supplies are available and which do not have fans. I am sure that they could also arrange to have a unit adjusted to output 12v for a nominal fee. Most of those there are also into computers as well as radios so they would likely bend over backwards to help out.

There are also units that allow the user to adjust the voltage externaly (a knob on the front of the case) but these are also more expensive since they also have voltage and amperage meters. The Astron VS-20M and VS-35M would be the models that corespond to the fixed voltage models above. As an example I just looked up the price for the VS-35M and it is $199.95 from HRO (free shipping).

In addition some of the RS and RM series can be ordered with a battery backup circuit that with the addition of a battery will also make the unit a UPS.

The RS-20A and RS-35A have been in production for ever and many people are running units that that have been in nearly continous use for 20 and 30 years. There are many of these on ebay. I just looked and there are currently 5 listings for the RS-35A and 13 for the RS-20A. So these are widely available.

The only noise complaints I have seen on these are that some units (perhaps 5%) have some transformer hum. But I am sure that the stores that sell these will exchange any unit that has this problem.

somebody · Post by **somebody** » Thu Aug 26, 2004 11:28 am

msde wrote:
somebody wrote:I asked about "where to purchase a brick PSU".
I replied with a link to a brick PSU. /shrug

If your complaint is that you couldn't add it to a shopping cart, then I apologize, but you could have just clicked on the words "buy online" on the page I originally linked.

http://store.mini-box.com/ituner/pw1220atxmip.html

What you have linked is a dc-dc converter. By brick PSU, I mean a PSU shaped like a block. If you have a better way of describing what I mean then please tell me.

somebody · Post by **somebody** » Thu Aug 26, 2004 11:49 am

Thanks for the info hvengel. I might go with one of the options you described if I am not able to decrease the amount of power I use. Otherwise, I'll probably purchase the 120W PSU that silvervarg mentioned.

msde · Post by **msde** » Thu Aug 26, 2004 12:14 pm

somebody wrote:What you have linked is a dc-dc converter. By brick PSU, I mean a PSU shaped like a block. If you have a better way of describing what I mean then please tell me.

Ah, I see what you mean now. My personal vision of a "brick PSU" consists of two parts, the brick (AC to regulated DC in) and the PSU (DC to ATX standard DC converter).

Have you considered making an adapter to let you wire 2 bricks in parallel?

hvengel · Post by **hvengel** » Thu Aug 26, 2004 12:43 pm

Somebody the solutions I listed will have 200 to 300 watts continous capacity depending on which unit you select and have peak capacities that are significantly higher (400 to 500 watts).

The real limitation is the internal to the PC DC to DC unit. The one the msde posted a link to is a 200 watt unit and when I looked at thier web site I thought that it said that the 200 watt rating was continous and that it would handle peaks 50% over the rated power. So if my memory is correct about the DC to DC unit then the Astron RS-35A with that unit is about like having a 300 watt conventional PC PSU only with lower ripple and tighter voltage regulation.

These power supplies are designed to handle loads that are much more complex than a PC and can go from milliwatts (receive only) to 100s of watts (transmitter on) and back very quickly and very often while at the same time requiring very clean tightly regulated power. Therefore these are somewhat over kill for this application.

This should handle just about any PC short of a real power hungy monster. So I would not try to use this to power a dual Operton machine with a 5 disk raid array and a NV 6800 graphics card. But it should be fine with any single CPU, single or dual hard drive machine with a GPU that is moderate in power use (>50 watts). In short just about any typical PC. Again the real limitation is the DC to DC unit and with a more powerful DC to DC unit it would be possible to pair it with a ham radio power supply that could power any PC no matter how power hungry.

Total cost for a RS-35A and the DC to DC device will be about $200. With some what lower power capacity the RS-20A and the DC to DC unit would cost about $150. So this is not cheap but also not totaly out of the question either. So the slightly higher cost is the real draw back.

The other thing to keep in mind is that you will have to fabricate the cable to go from the RS-35A/RS-20A to the DC to DC unit so this will add to the cost and effort needed. With large enough DC power cable you could place the RS-35A/20A a significant distance from the PC.

Edited to add - I just checked the specs on the DC to DC device and it is about 204 watts continous and 295 peak. So my memory was mostly correct.

somebody · Post by **somebody** » Thu Aug 26, 2004 1:11 pm

I wonder how much Zalman's fanless external PSU is going to cost. If it is less than $200, I might choose it instead.

silvervarg · Post by **silvervarg** » Fri Aug 27, 2004 6:45 am

Note that the link msde posted might not be very good for ATX boards.

Eg.
Compact design, less cables. The PW-200-V is the only cableless micro-atx dc to dc power supply for. Compatible with an entire range of mini-itx motherboards (as well as other board types) such as VIA EPIA M 6000, EPIA M 9000, EPIA-M 10000, EPIA-1000 MII, provides cool, silent power for your small mini-itx board from a single 12V power source.

No square 4-pin-plug etc, so it might not work with many normal boards.

If you want to use a HAM power supply make sure the DC-DC board likes 12V (or something close). Many recent brick-PSU + DC-DC kit uses a higher voltage, like 20V. I guess this might partly fix the heat problem in the brick without adding a lot of cost or weight to the system.

Link19 · Post by **Link19** » Tue Oct 05, 2004 5:32 pm

What about the Astron SS series? Will any of these work for a PC power supply when used in conjunction with the 200WATT micro DC to DC power supply? I'm looking to power an underclocked and undervolted Athlon system being fanless. Will any of the Astrons fit in your PC case where a power supply normally goes? And do they run hot?

silvervarg · Post by **silvervarg** » Wed Oct 06, 2004 1:40 am

Thanks for the tip. I did a quick search for it, and it seems to be nice swiching power supplies that produce 12V DC. At least the smaller models are fanless. They are made with external enclosures, so if put internally in a computer it might not be wise to use the full power for too long due to heat.
The only problem I see with this supply is cost (around $100 and then you still need to DC-DC board and cabels).
If you can do with around 100W a brick PSU will be smaller and much cheaper.