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Discussion Starter #1
Is there anything wrong with replacing the 12v wire on a pwm fan with a 5v wire? I'm doing this to a spare 4 pin extension wire atm because I want to reduce the speed/minimum speed of my pwm intake fans.
 

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Is there anything wrong with replacing the 12v wire on a pwm fan with a 5v wire? I'm doing this to a spare 4 pin extension wire atm because I want to reduce the speed/minimum speed of my pwm intake fans.
Voltage might be too low to run motor or too low for motor to reach high enough speeds. For example 2500rpm Ty-143 at 5v is 1165rom, Gentle Typhoon 3000rpm at 5v is 1251rpm. On PWM control my TY-143 idle down to 550-600rpm .. that's slow enough for me. ;)
 

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Discussion Starter #4
5v is enough for 800rpm on my p14's and that's 100rpm higher than I ever use on my intakes so I'm ok with the loss of rpm. The upside is I've reduced minimum rpm from 300rpm to 140rpm, I only need 200rpm so it's ok. I wanted the reduced minimum rpm for less dust buildup during idle.
I considered using 7v for more rpm's which would be better but 5v is easier and possibly safer for the psu.
 

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Good to know, thanks!
 

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Discussion Starter #6
Anyone else thinking of doing this instead of buying a low noise adapter(most low noise adapters don't reduce minimum rpm very much like this adapter) you can get very cheap step down buck converters and use any voltage you want like 8v. If you were going to use 5v it would be better to do it the way I did it but a buck converter is much cleaner(can just run off the 12v your pwm fan already has) and can just be electric taped to your pwm wire.
 

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but a buck converter is much cleaner(can just run off the 12v your pwm fan already has) and can just be electric taped to your pwm wire.
You seem having wrong understanding of the word CLEANER ... such low end buck converter will backfire electrical noise and the pollution it might cause instability at other circuits.
The humble voltage stabilizers L7808 or L7806 this is a much safer equivalent
 

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Discussion Starter #8
Yeah ok that looks 'cleaner' and safer than the buck converter, no variable output voltage though.
 

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Yeah ok that looks 'cleaner' and safer than the buck converter, no variable output voltage though.
You may combine L7809 and L7808 and L7806 in a single PCB and use a miniature switch (three positions).
The most classic three steps adjustable mini PSU.


(tip of the day ... use quote at your reply so the other member to get notified by the forum engine)
 

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Discussion Starter #10
Finally got some l7808cv linear voltage regulators and ghetto rigged a pwm 8v low noise adapter.
A few pictures of the construction.
2474054


Lots of hot glue for maximum ghetto rigged stability and safety.
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and inside the case
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I have it connected to my 120mm shadow wings 2 pwm PSU fan. It works as expected minimum rpm has been reduced from 460rpm to 280rpm and maximum speed has been reduced to 750rpm from 1100rpm. I also stress tested it for 10min at maximum fan speed and therefore heat dissipation inside the regulator to make sure it wasn't going to melt the hot glue, which is 0.48w (0.12A max current x 4v = 0.48w). It ran fine the hot glue surrounding the regulator barely felt any warmer than room temperature after 10min.
2474061
 
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