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noisy fan :(

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Feb 26, 2002
i very bad in this moment , i buy new cpu cooler for my xp2000
and my board Epox 8k3a+
i very frustracion
my buy is ThermalRight AX-7 w/ Delta 80 Model FFB0812EHE, 80 CFM.
because ppl say this fan is the better in the world
but is to noisy , the noise it makes is like an airplane
im looking for another fan that operate at a low noise level but
with a good air volume but without noise

i need finish my pc this weekend

thanks my friends

i desesperatly for repair this
do a 7V mod instead of 12V will quiet that fan down but you will loose performance as well
How about using a rheostat to control the voltage which would affect the fan speed & minimize the turbulence created by the leading edge therefore decreasing the noise?:D If you need help doing any of the mod just continue to post on this thread. Just remember that with 7V mods you will not be able to monitor the fan rpm.
where can buy one rheostat
i phone a electronic shop and miss i need one rheostat
she answer what rheostat ??

i no have idea what reostat specifications
I'm not sure how to explain it so that the lady from the store can understand it. How about telling her that you need a variable resistor or how about telling her that it is like a like a potentiometer but with higher capacity.....

pics courtesy of Hoot
you know specifications

ohms, amp, watts??
what info i need for buy

Gosu said:
DELTA 80MM FFB812EHE 82 cfm aprox
DC 12v 1.35A
This is how to compute it;

Ohms = (MaxVoltage - MinVoltage) / Amps

Ohms = (12V - 7V) / 1.35A
Ohms = 3.7

Watts = Voltage X Amps
Watts = 12 X 1.35
Watts = 16.2

The closest you can get to that spec would be 25W. I dont think the 5W will handle that great fan. Better to mod it since it is cheaper to buy the rheostat & you can easily turn it up when you want to lose some of your hearing:eek:
here is the spec on that fan
according to that the fan draw

10.80w / 12V = 0.9A

at 7V fan operation the reostat needs to be
(12V-7V)/ 0.9A = 5.56 Ohms
(12V-7V) * 0.9A = 4.5W

The best is a 5W 10 Ohm reostat but 100 Ohm will do too.

one can also modify the connections to change the 3 leads 100Ohm reostat to a 50Ohm 2 leads reostat by connecting the 2 ends together.
connect it as follow

12V -> reostat 2 ends
reostat middle lead -> red fan wire
black fan wire -> PSU black wire
Last edited:
Sorry about the babo math. I guess I'm too used to it.
I use some Ohms law and physic formula to solve it. Here are some more explanation

W = V * I
where W is watt
V is voltage
I is current in ampere

V = I * R

R is resistance in Ohms

Since your little mod circuit (fan and reostat) is in serial I also use

Vt = sum of V components
12V = 7V (fan) + 5V (reostat)

Also the reostat mod to 50 Ohms use the Ohm's law parallel resistance formula. Actually, I was wrong the total max resistance would be 25 Ohms. When 2 resistors hook up in parallel. Assume your reostat dial is at middle (max resistance) each side is 50 Ohms

1/ Rt = 1/ R1 + 1/R2

or Rt = 1/ (1/R1 + 1/R2) = 1/ (1/50 + 1/50) = 25 Ohms

more here

which part you don't understand. Tell me I'll explain. Hope that help
in my country (mexico ) no sale reostat only potenciometers

i can buy potenciometer 5w 10kohms??

or what i need
how i say a saleman in electronic shop

he say what all potenciometers is in kohms
10, 20, 50, 100, 250, etc
potential meter is the same as reostat just different name for it

Kohm is Kilo Ohms. You don't want that.

The best is 5W 10 Ohms potential meter, 100 Ohms one is fine too. Just do the mod as I show above.
in my city no sale in ohms

salesman say 5w 500ohms is more litle
Yes, a potientiomiter and a variable resisor will do the same thing. If, however you can only find KOhm rated potentiomitors, you will either have to buy one online or hook up a second resistor in parallel to decrease the effective resistance.

If you go with plan B, you will need a resitor close to 3.7 Ohms with the 10K potentiometer. You will take this resisor and hook it up so it will go around the potentiometer. Then they will feed the fan. The resistor will drop the total resistance down to around the correct resistance.

Pictures of course!