Power Supply for 8th gen NUC

[Superdad]

On 4/4/2020 at 12:51 PM, MichaelH said:

UpTone Audio JS-2 $925
- two outputs, 5-12V, 5A each

Hi:

Thanks for the mention.  Just to be clear for others who encounter this thread, our choke-filtered, dual-output JS-2 can deliver 7.4 amps at 12V all day long from a single rail (provided AC mains input is 120/240V; max current at 12V is less with 115/230V or 110/220V)—and barely even get warm. 

The 5A rating is for when a user adjusts to 5V output.

 

There are more than a hundred people using JS-2s to power Intel NUCs and Roon Nucleus+. Yes the DC input jacks and general spec sheets of those machines say 19V, but as pointed out, the actual NUC logic board documentation shows 12~19V.

 

There is some question about the new 10th generation NUCs: Intel’s detailed docs no longer show a 12~19V input range, but it is not at all certain as to if that is true or if it was simply an oversight by whoever was writing/editing the document. 
I really doubt that Intel changed all the DC-DC voltage regulators on the new boards to ones that don’t run from 12V just as well.
 

[Remember, there are no chips in a computer that run directly from any of these high voltages—it ALL gets stepped down to 3.3V, 2.5V, 1.2V, 1.1V for the chips themselves.  Higher input voltages simply allow for lower current outboard supplies; it’s all about the watts and the efficiency of the DC-DC switching converters on the motherboard.]
 

Maybe someone will loan me their 10th-gen NUC for a day so I can run current and voltage tests to definitively determine what’s up with these models. 

[Superdad]

2 hours ago, NYCEnglish said:

Is 12V sufficient when the NUC has two internal SSD drives installed?

 

Sure, 12V is fine.  It is about current capability not voltage level. Extra drives just add a small additional current requirement (SSDs don't draw much though.)

[Think of current as strength to lift, and voltage as height of shelf to lift up to.]

[Superdad]

@Mops911: What @barrows says is correct, but it applies mostly only to equipment that uses linear voltage regulators for step-down of voltage. Less drop equals less heat to dissipate.

 

However, in an Intel NUC, Roon Nucleus, laptop, general purpose computer, there is nary a linear voltage regulator in sight—certainly not at its DC input greeting the 12V or 19V from an external supply. Such computers are filled with DC-DC switching regulators, and those truly don’t care what voltage you give them—efficiency is the same at any voltage in their range.

 

So this goes back to my original point, which is that for these computers it is all about the wattage drawn. Let’s say your computer draws 36 watts.  (And of course volts * amps = watts.) There will be no difference in heat, efficiency, or sound if feed it with a 19V supply capable of 2A versus a 12V supply capable of 3A (this for example only; power supply should have a bit of headroom above actual wattage draw).