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Which resistor to slow down my 6600's fan ?

Last response: in Graphics & Displays
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January 18, 2005 2:18:49 PM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

We have discussed the possibility to quiet down the original fan soldering a
resistor on the fan's wire but I am not sure which resistor I should try. We
started from 10K Ohm then 1k, then even 27ohm....

I am a bit confused, any experience ?

More about : resistor slow 6600 fan

January 18, 2005 2:18:50 PM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

OK. You made me curious so I dug out my multimeter and measured a case fan
that I had modded this way. I have two resistor in parallel. Each 150 ohms
for a total resistance of 75 ohms. This probably cuts to fans RPMs by about
half. So a good value to start with might be around 27 ohms and then go up
from there. Be sure to use at least 1/2 watt resistors. For this
particular mod the 150 ohm resistor are both 1/4 watt for a total of 1/2
watt.

Sorry for my earlier mistake. It had been a while since I had played with
that. I hope nobody burned up anything based on my errant post.

DaveL


"MaSTeR" <sorry@nospam.com> wrote in message
news:3549kpF4htn50U1@individual.net...
> We have discussed the possibility to quiet down the original fan soldering
> a
> resistor on the fan's wire but I am not sure which resistor I should try.
> We
> started from 10K Ohm then 1k, then even 27ohm....
>
> I am a bit confused, any experience ?
>
>
January 18, 2005 8:59:27 PM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

Resistors go up in what is known as preferred values.

For 12v fans.

anything between 18, 22,27,33,47 and 68ohm can be used.

you will find the next highest after 68 is a little too high and the fan may
have difficulty starting up.

I find either 33,47 or 68ohm gives a good reduction in noise. A lot depends how
efficient the air flow is through the case on choosing the right value.

47 or 68 I find give good results. Dependant on the fans used.

As not to create more heat I suggest 3watt wirewound type, as they are easily
obtained. They are still quite small in size and will easily support a couple of
case fans if necessary.

Wattage divided by voltage = Amps
voltage multiplied by Amperage = Watts

etc etc.

Mike
Related resources
January 18, 2005 9:17:12 PM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

Just noticed the subject line and you mention its to slow down the fan on a 6600
card.

Sorry but the brain is a little slow today... case fans are one thing but the
gpu's on these modern graphic cards run quite warm and the fans tend to be on
the small side... so I would suggest you don't slow it down too much.
certainly no higher than 33ohm. Choose 22 or 27ohm.

I run a 6800gt card and like you I find the noise is too loud for my liking.

What I did was to make a blank pci card out of a piece of pcb board, matched to
the shape of a proper pci card with a round cutout to carry a low noise 80mm
fan. I then mount it on an old card back plate and fit it in the adjacent pci
slow below the graphics card.. a bit of trouble I know but it works very well
and is almost silent.
Obviously make sure there is no possibility of a metal contact taking place
where it plugs into the pci slot. :-))))) LOL

The other option is to get one of the VGA Silencers by Artic Cooling, these work
quite well too, but for some reason the fans they currently use are not so quiet
as the ones they used to fit when they first marketed the product, but are still
a better than the original fan.


Mike
Anonymous
January 19, 2005 7:42:07 AM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

On Tue, 18 Jan 2005 11:18:49 -0000, "MaSTeR" <sorry@nospam.com> wrote:

>We have discussed the possibility to quiet down the original fan soldering a
>resistor on the fan's wire but I am not sure which resistor I should try. We
>started from 10K Ohm then 1k, then even 27ohm....
>
>I am a bit confused, any experience ?
>
>

Putting a resistor in series with a fan runs the risk of the fan
intermittently failing to start on power-up. A very inexpensive way of
irreversibly damaging the GPU.

John Lewis
Anonymous
January 20, 2005 4:56:01 PM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

"MaSTeR" <sorry@nospam.co.uk> wrote in message
news:356pe1F3pukvtU1@individual.net
> "John Lewis" <john.dsl@verizon.net> wrote in message
> news:41ede454.35615683@news.verizon.net...
>> On Tue, 18 Jan 2005 11:18:49 -0000, "MaSTeR" <sorry@nospam.com> wrote:
>>
>>> We have discussed the possibility to quiet down the original fan
>>> soldering a
>>> resistor on the fan's wire but I am not sure which resistor I should
>>> try. We
>>> started from 10K Ohm then 1k, then even 27ohm....
>>>
>>> I am a bit confused, any experience ?
>>>
>>>
>>
>> Putting a resistor in series with a fan runs the risk of the fan
>> intermittently failing to start on power-up. A very inexpensive way of
>> irreversibly damaging the GPU.
>>
>> John Lewis
>>
> Points of view. I ran my overnight and it is just 7C hotter than before.
> The noise is completely gone and the fan even if slower doesn't struggle
> at all.

depends on what's your room temp +7C can be already way too much..next
summer!

Besides:
> - if the card gets hotter the fan will increase its speed, thus if stuck
> (very unlikely) will start anyway

dont bet on it since the resistor inline will affect this speed as well..
the fan won't start spinning if there is not enough current (amps)
available - even more problematic if the fan must spin "uphill" (card
mounted upright)


....
Anonymous
January 20, 2005 5:05:33 PM

Archived from groups: alt.comp.periphs.videocards.nvidia (More info?)

"MaSTeR" <sorry@nospam.com> wrote in message
news:3549kpF4htn50U1@individual.net
> We have discussed the possibility to quiet down the original fan
> soldering a resistor on the fan's wire but I am not sure which resistor I
> should try. We started from 10K Ohm then 1k, then even 27ohm....
>
> I am a bit confused, any experience ?

Usually a 10-20% rpm reduction is sufficient to silence a fan.
1) Find out how much the actual current through the fan is
2) substract 10-20% from this current (desired current)
3) calculate the resistor value based on the difference of the actual
current and the desired current.

simple like that! BTW, u dont need 2 Watt - 1 Watt will be plenty enough
!