Quiet computer

[soralx at cydem.org]

> >>> You might wants to consider using a low-power 'brick'-type AC->DC
> >>> PSU (~90W?) and a DC-DC voltage converter that plugs directly into
> >>> a mainboard's power connector. This will be quite noiseless.
> >> Do you have any recommendations? Ideally it would mount on the case
> >> (<http://www.logicsupply.com/product_info.php/products_id/134>) like
> >> the current power supply does but I'm open to other options
> > something like this (random example):
> > http://www.logicsupply.com/product_info.php/products_id/596
> 
> The only types of power supplies with which I'm familiar are the ones  
> that typically ship with most cases, so I'm a little confused by  
> this, excuse my obvious ignorance :)
> 
> What does the DC-DC converter do, if the AC-DC converter supplies DC  
> power?

it converts the single supplied DC voltage (that is sometimes allowed to
range as much as 6Vdc to 20Vdc) to multiple DC voltages required by the
mainboard and other devices (+12V, +5V, +3.3V, -5V, etc)

> What would be an example of this AC-DC converter?

just any AC->DC power supply that's output is within a DC->DC converter's
input range; e.g., a laptop power adapter

> Could it power two
> 3.5" hard drives in addition to the motherboard?

depends on the DC->DC converter you use
3.5" hard drive sucks a lot of juice at 12V line, so the converter must be
able to supply that; any converter destined to be used in Intel Pentium4
system _probably_ will work (typical model name for such a beast would
look something like '120W', versus '60W' that can supply little power
at 12V)
note, however, that if you use a good, well filtered AC->DC power supply
that produces 12V, you can feed this voltage directly to the hard drives
(I think you can; I'm not sure if the groud loop will affect anything)

Also, I believe that the more powerful version of DC->DC is more efficient
at the same load level than less powerful (i.e., 120W vs 60W)

> How does it differ from a regular power supply?

much smaller in size, _theoretically_ longer life before {failure because
of old age} (assume same temperature), less wires, supposedly more
efficient and lower power. The latter, in particular, means that the
whole AC->DC->DC system will generate little heat, and thus won't require
active cooling (you can even keep the AC->DC PSU outside of case so it
doesn't heat up its interior & take up space).
Of course, a regular ATX PSU won't dissipate a lot of heat either, yet
just disconnecting the fan is hardly a  solution.
One advantage of such a power source is that realizing uninterruptible
power is rather easy: just connect a battery :) This way, you can easily
replace a failing AC->DC PSU without sending the server down, too.


[SorAlx]  ridin' VN1500-B2