Production Noctua 40mm 20mm width fan for ENP-7660b and fx600

Mackan

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Jun 2, 2016
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Who bought all the black ones? ;) It says on pre-order now. I managed to get hold of one, but had planned to get two...
 

hooning_hippo

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Jul 11, 2022
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Is the Noctua fan you use to replace the stock fan the 5V or 12V model? In the fan swap guide it says 5V on it but the stock fan is 12V...?
 

Overtek

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Is the Noctua fan you use to replace the stock fan the 5V or 12V model? In the fan swap guide it says 5V on it but the stock fan is 12V...?
Well spotted yes 5Vdc is used, with loads no more than 500W.

Why 5V instead of 12V. Very simply a 40mm noctua fan doesn't have sufficient airflow to cool ENP-7660B under high loads. Also the startup voltage of a Noctua 12V fan is high, around 6.5V. The fan voltage mapping of ENP-7660B means it sits at around 3Vdc to around 480W. So a 12V noc would not spin up at all until thermals reach a point where it comes on. If the load is not near the PSU limit it should cool the PSU sufficiently to move the fan map back down to 3Vdc and so it would cycle on/off. That also then causes the power supply to run much hotter leaving higher residual thermals in the system. The problem is the bearing tech used in Noctua, their fluid bearings can't do high rpms that a dual ball bearing can and that's what limits the max airflow.

Running a 5V with restricted load means we actually end up with a cooler running power supply against stock as at 60% duty cycle (3/5) as opposed to stock which runs at 25% duty cycle (3/12). In a simple linear comparison you'll calculate you get a fraction more cfm from a Noctua running at 60% duty cycle compared to the stock ADDA fan or Yate Loon (which has less cfm than the ADDA fan) - For small form factor this means less heat left radiating into the system.

In short Silverstone FX600 will run hotter than ENP-7660B as the Yate Loon used in the silverstone runs at a lower rpm and has less airflow and although the airflow should be similar between Adda and 5V Noctua, we found the Noctua runs the PSU cooler than the Adda.
 
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robbee

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The fan voltage mapping of ENP-7660B means it sits at around 3Vdc to around 480W. So a 12V noc would not spin up at all until thermals reach a point where it comes on

What happens to the 5V Noctua when load goes above 480W though? Will it not break when the voltage goes too much above its rated voltage?
 

Overtek

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May 22, 2017
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What happens to the 5V Noctua when load goes above 480W though? Will it not break when the voltage goes too much above its rated voltage?
it shortens the fan life. takes about 1-2 months, according to Noctua, ie if you were to run it at 12V constantly.

But it doesn't suddenly kill it.
 

M-Tron

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Jun 13, 2023
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Does this apply to (more or less) any flex PSU? I have an Argus 250W PSU that only powers a 11400/MB/RAM. Would you also recommend a 5V Noctua fan for this one?
 

Overtek

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Does this apply to (more or less) any flex PSU? I have an Argus 250W PSU that only powers a 11400/MB/RAM. Would you also recommend a 5V Noctua fan for this one?
No, it doesn't apply more or less. It depends on the fan control circuit and it's function / mapping. The PSU you have looks a particularly old circuit design >10-15 years and is fairly inefficient. That results in higher thermal losses.

So you'll certainly want to understand the spec of the existing fan to compare its CFM. Also the no load voltage of fan control circuit and understand if it's load control and or thermal controlled. Consider also that fdb fans like noctua have a much higher start up duty cycle approx 55% compared to dual ball or sleeve bearing (Sleeve bearing fans are not usually deployed, unless PSU is cheaped out for absolute min cost point, this would usually always be accompanied by a short warranty period)

Best of luck with it and be careful. Some older and budget designs may not implement capacitor voltage discharge on mains disconnection as they should do under various compliance regulations. So there maybe around 420-460Vdc retained in the primary cap, and present, of course, when powered.
 

kotas

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Dec 2, 2023
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@Overtek are you still selling these custom 2 pin black Noctuas? Or even the cream ones.
I did fan swap on my ENP 7660B since it was sounding mini jet using the adapter Noctua provides with the fan but after maybe a week I did notice that PSU runs very hot and the fan was not spinning. I think my total system consumption should not be more than 180W.
After taking the Noctua fan out it was a little bit smelly, but so was the PSU. Luckily it still works. I used 5V 3pin version and with included Omni Join adapter made it 2 pin. It was spinning in after i boot the system but must have stopped after a while. Noticed approx after a week.
So I would like to try yours fan made with more professional care since I am not really satisfied by the Adda fan the ENP has. Sadly while playing Cypberunk it is almost as loud as GPU fan or maybe even more.
Thanks
 

Overtek

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May 22, 2017
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@Overtek are you still selling these custom 2 pin black Noctuas? Or even the cream ones.
I did fan swap on my ENP 7660B since it was sounding mini jet using the adapter Noctua provides with the fan but after maybe a week I did notice that PSU runs very hot and the fan was not spinning. I think my total system consumption should not be more than 180W.
After taking the Noctua fan out it was a little bit smelly, but so was the PSU. Luckily it still works. I used 5V 3pin version and with included Omni Join adapter made it 2 pin. It was spinning in after i boot the system but must have stopped after a while. Noticed approx after a week.
So I would like to try yours fan made with more professional care since I am not really satisfied by the Adda fan the ENP has. Sadly while playing Cypberunk it is almost as loud as GPU fan or maybe even more.
Thanks
Safety is your responsibility, should you be in any doubt seek a professional for the following.Measure your fan header voltage with ps on taken active low