Article: Computer Audiophile Pocket Server C.A.P.S. v3 Zuma

[Miki]

Nice Chris. This is the setup I envisioned for my CAPS (sort of). One note. Is it just me or the copper pipes of FC5WS-EVO are not long enough to cover the entire CPU where is located on DH77EB board. It seems that the pipes are covering only about 50% of CPU. This will somewhat diminish cooling efficiency. Please correct me if I am wrong.

 

On the other note, if your input is higher than 12V into PicoPSU, could you not use the Wide Input version of Pico ? Not sure if it is available in 150W though, I have seen 120W.

[Miki]

I tend to agree with i3-3220T. I was going to use it for my CAPS and Intel DH61DL but that board has a weired CPU and 12-pin power placement, so it is out. Anyway, I exchanged some emails with Vinnie from Red Wine Audio and he said:

 

"When the switch is in BATT mode, it only runs on the internal battery packs. If you switch to AC mode, it will charge and play at the same time (not as clean as BATT mode since you'll be using the charger).

 

When it needs charging, the red light on the power switch will begin to blink. At that time, you can switch to AC mode if you want to keep on playing, or shut down your server and then switch off your BL to allow it to charge."

 

I don't think there is any smart logic in BL to power down the server properly.

[Miki]

Miki. In the images of Zuma, that star shaped metal plate contraption with the "Streatcom" label on it sits right over the top of the chip. So I'm not sure what you mean? Do you mean that the heat pipes under this don't go far in enough? They are connected to that metal plate on top right? So why should this matter...? As heat is collected by the plate, then conducted away via the pipes... I'm no computer engineer, but isn't this how heat dissipation is working?

 

Well, I am a sort of thermal related engineer (in different field though) and my point is this: CPU cooling is implemented by thermal conduction in fanless cases. Convection happens here only by free flow of air trough and around the chassis (unlike the fanned cases where air is pushed around providing more efficient cooling). Cooling by pure conduction works well only if the heat sink is of large enough capacity to, well, conduct unwanted heat away from the source and be cooled enough by little convective air movement in the room and radiation to dissipate the heat.

 

In our case the size (mass) of the case coupled with little air draft should provide enough cooling power (95W for FC5) to keep the CPU in the normal operating range of 50-60 C. However, what conducts the heat from CPU to the case are the copper pipes. If the pipes are connected to the CPU only partially the heat conduction between the pipes and CPU (or the plate on top of CPU) slows down and temperature of CPU goes up. You can think of the connection between the pipes and CPU as a tap - fully connected and the tap is wide open, partially connected the tap is partway shut.

 

If one wants to be annal about this, one can purchase extra set of QuickCool heat pipes, bend them using something like Spring Type Tube Bender from ebay which they use to bend copper pipes on air conditioning units since they kink easily and customize the length of heat pipes.

 

Off course, this is all academic since Chris said that it really didn't matter since the temperature of CPU was normal. If one is patient enough to wait for i7 i3770T or use i5 or i3 3220T (my preference) it is even less important.