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7 Volt mod

LOUD is not the answer! Then again.. neither is electrical fire...
 
Necrofire said:
That fan blows a crap load of air. It's some cheap fan with 7 fins. It's just loud.

I traded it for the quiet one I have, and put a quiet 80mm on my graphics card in place of that. Now my system purrs along.

For $3 more than the Antec Tricool fans, I got a variable fan that is ~5dB quieter on its lowest setting, and is louder on highest setting than all these items combined...
1. 3 hard drives
2. stock 8600GTS fan
3. cpu fan on highest setting
4. 2 80mm fans in power supply

It's like a miniature tornado when I turn it up.
Click to expand...

loud is bad :P all my systems rate as either quiet or silent (the air conditioner here drowns them out from two rooms away)
 
Yeah, that's a link for a basic switch-type. The one I had in mind was based on a rheostat and (depending on the load of the fan or fans), can run anywhere between 4V and 12V.

In fact, I think I may still have a couple of the rheostats I used in the garage. All you have to do is cut the 12V wire and solder the rheostat in place. Pretty easy stuff.

EDIT: Found this:

http://www.virtual-hideout.net/guides/rheostats/index.shtml
 
I guess I don't understand what he is trying to do here. He wants to reduce the voltage to the 12 volt fans but he wants to do it cheap. So I don't see where building a 30 or 40 dollar fan controller would do when you can buy one just as cheap. Fact is his first link shows a strange way of doing it, his brother has a degree in electrical engineering yet won't help him figure this problem out. So far there are half a dozen different ways to do it here but all cost more than 3 dollars. My point is this if you want a whisper quite PC its going to cost more than 3 dollars.
Sorry truth hurts :laugh:
 
go to radio shack and buy some (large diodes #1N4003), they will drop the voltage down 0.75v for each one you use so if you use 8 of them soldered end to end you will drop your voltage from 12v to 8v, you can add as many as needed to reach the desired fan speed but you might not get enough cooling if you go too slow.

NOTE: diodes only allow voltage to go in one direction just like leds so pay attention to how you connect them, the stripe always goes on the fan side for the red wire and if used on the negative wire the stripe goes to the plug side away from the fan.
 
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strick94u said:
I guess I don't understand what he is trying to do here. He wants to reduce the voltage to the 12 volt fans but he wants to do it cheap. So I don't see where building a 30 or 40 dollar fan controller would do when you can buy one just as cheap. Fact is his first link shows a strange way of doing it, his brother has a degree in electrical engineering yet won't help him figure this problem out. So far there are half a dozen different ways to do it here but all cost more than 3 dollars. My point is this if you want a whisper quite PC its going to cost more than 3 dollars.
Sorry truth hurts :laugh:
Click to expand...

Nah, mine only costs about $3 per fan or two.
 
t_ski said:
Nah, mine only costs about $3 per fan or two.
Click to expand...

i pay upto $30 per fan... thn again, i'm willing to pay for quality here.
 
Part of the fun in those days was being able to make something like these fan controllers. I must have made half a dozen of them. Today, I have a Zalman MFC1 that I use instead, and I love Yate Loon fans: they're inexpensive, not too loud at full speed even though they're pushing a good amount of air, and at 5v they're quieter than any other fan in the system.
 
t_ski said:
Part of the fun in those days was being able to make something like these fan controllers. I must have made half a dozen of them. Today, I have a Zalman MFC1 that I use instead, and I love Yate Loon fans: they're inexpensive, not too loud at full speed even though they're pushing a good amount of air, and at 5v they're quieter than any other fan in the system.
Click to expand...

cant get yates in aus :( i get teh nexus orange and run them at 7v :) pretty much the same as you. (i've heard that nexus orange are rebadged yate loons)
 
keakar said:
go to radio shack and buy some diodes, they will drop the voltage down 1.5v for each one you use so if you use 4 of them soldered end to end you will drop your voltage from 12v to 8v, you can even add a 5th diode to get it down to 6.5v if you really need to but you might not get enough airflow if you go too slow.

NOTE: diodes only allow voltage to go in one direction just like leds so pay attention to how you connect them, the stripe always goes on the fan side for the red wire and if used on the negative wire the stripe goes to the plug side away from the fan.
Click to expand...

Diodes drop approximately .5 volts per diode;)
 
Well, doesn't the power get converted to heat?
Heat = bad in my book.
Rheostats are nice, but a little pricey. I'm just gonna leave my setup as it is:
Quiet adjustable fan I already own in front, 80mm quiet fan on GPU, and tornado fan on desk somewhere.

EDIT: I'm so stupid, I had just assumed that my 12 volt fan could not start at 5 volts. Well, I'm thinking of reusing my 12 volt tornado at 5 volts, since I just tried it and it's really quiet.
I can't believe I never thought of just trying it.
 
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Usually with a rheostat, if the ground wires are connected to the third terminal on the rheostat, then it will generate a lot of heat. When I made ones for my rigs I did not do that, and never noticed any issues or excess heat.

Many fans can start at 5v, but there are some that won't start until 7v. In that case, you just need to crank it up for the fan to start, then turn it back down to where you want to run it at.
 
strick94u said:
Diodes drop approximately .5 volts per diode;)
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the ones im using (1N4003) have a 0.75v voltage drop so it depends on the size you use. with the ones i use it takes 2 to get a 1.5v drop measured with a multimeter.

the main advantage of the diode over the resister is the resistor gets way way hotter than the diode will so while the diode will be very warm, the resistor will be HOT
 
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I suppose that may depend on the resistor you are using. None of the resistors I've used got hot, however I didn't use them for fans.

BTW, a diode is basicly a one-way resistor. Another advantage is the voltage can't go back through the wrong way.
 
Necrofire said:
Well, doesn't the power get converted to heat?
Heat = bad in my book.
Rheostats are nice, but a little pricey. I'm just gonna leave my setup as it is:
Quiet adjustable fan I already own in front, 80mm quiet fan on GPU, and tornado fan on desk somewhere.

EDIT: I'm so stupid, I had just assumed that my 12 volt fan could not start at 5 volts. Well, I'm thinking of reusing my 12 volt tornado at 5 volts, since I just tried it and it's really quiet.
I can't believe I never thought of just trying it.
Click to expand...

most times its just the 120mm + fans that have trouble starting on only 5v
 
t_ski said:
I suppose that may depend on the resistor you are using. None of the resistors I've used got hot, however I didn't use them for fans.

BTW, a diode is basicly a one-way resistor. Another advantage is the voltage can't go back through the wrong way.
Click to expand...

when you start putting some juice through em resistors will get hot enough to burn your fingers.
 
keakar said:
most times its just the 120mm + fans that have trouble starting on only 5v
Click to expand...

That's waht I thought also. Seeing as how this fan is a 120mm fan, I had just assumed it didn't start at 5 volts. It makes sense, the smaller the fan, the smaller the motor (generally) and the less resistance to "turning over."
Anyway, the fan turns over at 5 volts, so I'm happy that I don't have to mess with 7 volt crap or anything. What I might do though is put a switch that'll go between 5 volts and 12 volts.

Molex___12V___
.....................|__...........____Neg____molex
Molex___5V____...|.........|
......................|..|........|
....................Switch____Fan

Yay for ascii diagrams:rockout:
 
Necrofire said:
That's waht I thought also. Seeing as how this fan is a 120mm fan, I had just assumed it didn't start at 5 volts. It makes sense, the smaller the fan, the smaller the motor (generally) and the less resistance to "turning over."
Anyway, the fan turns over at 5 volts, so I'm happy that I don't have to mess with 7 volt crap or anything. What I might do though is put a switch that'll go between 5 volts and 12 volts.

Molex___12V___
.....................|__...........____Neg____molex
Molex___5V____...|.........|
......................|..|........|
....................Switch____Fan

Yay for ascii diagrams:rockout:
Click to expand...

noooo dont do the switch, its rare to happen but it can "bridge" the two if the switch fails and while the psu protection should kick in and trip, you always have that chance something can be hurt by a short. just not worth risking for a minor convienience

http://www.kpsec.freeuk.com/components/switch.htm#standard
 
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keakar said:
noooo dont do the switch, its rare to happen but it can "bridge" the two if the switch fails and while the psu protection should kick in and trip, you always have that chance something can be hurt by a short. just not worth risking for a minor convienience

http://www.kpsec.freeuk.com/components/switch.htm#standard
Click to expand...

I had already pondered that happening, and the switch I tested can't do that. I tested it, and as soon as it's about middle way, it's off for both sides, so I'm in the clear unless somehow the switch magically expands to contact both at once momentarily while switching. The switch I have is a SPDT, and it's nearly impossible to contact the opposite ends.
 
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Most of the fan controller I built for myself were made that same way. Only recently did I find the rheostat version. Never had any problems.
 
No need for a rheostat, I'm building a custom case and I won't need that much fine tuning for the fans, just a "low" setting and a "tornado" setting.
 
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