Is it safe to "stack" fanmates (and the likes)?

Nepenthe · Post by **Nepenthe** » Wed Nov 17, 2004 3:28 pm

With "stack" I mean to send the output of one fanmate into another one to further reduce the voltage.
Since I'm not really a electronic savvy person, I think I'd better ask first before I burn anything

Actually, I only have one Fanmate2 by Zalman, but I also have a Nexus NRC-1000 Noise Reduction Cable which converts 12V to 10V; and a NoiseControl EWMS Fan Voltage Control & Splitter, which can take 2 12V fans and reduce the voltage down to 6V.

Right now there are 3 fans in my Chenbro Gaming Bomb case, the CPU fan on the Zalman 7000, a 92mm Nexus intake and a 120mm Nexus exhaust, and very soon I'll be getting a Geforce 6800GT (probably a Galaxy with preinstalled NV Silencer 5) and I'm sure the fan on the NV5 will have to be dealt with too.

I've been using the lowest setting of the Zalman Fanmate 2 with my CPU fan, even overclocked it idles at below 30°C and peaks at 50°C, so I think it'd be reasonable to further reduce the fan speed, therefore I bought the Resistor Cable and the Voltage Control, but not really sure if it's safe to simply stack them.

Can someone give me some suggestions about the best way to use my stuff? My major concern is the CPU fan because it is quite audible even when FanMated down, and the Geforce will also need some drastic measure. The two Nexus fans are pretty quiet as they are.

Many thanks in advance!

burcakb · Post by **burcakb** » Thu Nov 18, 2004 5:59 am

I vaguely remember two fanmates in series don't work. I may be wrong. BUT a fanmate + inline resistor (like the Nexus noise reduction cable) work just fine. Just remember to put the resistor cable to the lead going to the FAN not the motherboard. I run both my Zalman7000s this way and I'm quite pleased.

Warning! Once you do that, I think you'll be finding the Nexus (especially the 120mm) too loud

there really is no end.....

Jan Kivar · Post by **Jan Kivar** » Thu Nov 18, 2004 8:14 am

burcakb wrote:I vaguely remember two fanmates in series don't work. ...

Surely two Fan Mates can be used in series.

If one turns a Fan Mate to the max., it acts as an 1,5V Zener diode - whatever voltage one puts in, out comes (input - 1,5V). E.g. 12V in -> 10,5V out, 5V in -> 3.5V out and so on.

So, by combining one Fan Mate that has been dialed down to min (5V) and another Fan Mate is connected in series, the output voltage will be around 3,5V. This particular combination is rather dull, as better solution would be to power the second Fan Mate from a 5V rail direcly, thus eliminating the other Fan Mate. But using two Fan Mates will enable the use of voltage range between 3,5-5V.

Nepenthe, I haven't played with my CNPS7000's fan, but if the fan is identical to the 92mm Zalman fan one can buy from the store, I can confirm that (at least my sample) it starts just fine with 3,5V (the fan is from CNPS6000). Though I think that the speed would be too slow to cool properly.

The easy solution would be to get more Fan Mates...

Cheers,

Jan

Nepenthe · Post by **Nepenthe** » Thu Nov 18, 2004 1:37 pm

Thanks to you all for the advices!
Today I serialized the Resistor Cable with the Fanmate and it really worked! Now the CPU Fan only rotates at about 750RPM

when the FanMate is turned way down, and thanks to Cool&Quiet, I now idle at about 34°C, need some extensive load test yet though.

@burcakb: Sadly, you are right, now I can finally hear the Nexus 120mm, well well well...

burcakb · Post by **burcakb** » Thu Nov 18, 2004 1:50 pm

Jan,

I suppose I didn't look carefully when I did the two fanmates. The fan on the Z7000 is NOT the same as the one sold seperately (I asked Zalman) though the practical differences are extremely small IMO.

Z7000 at 750 rpms cools just fine and the fan starts very reliably.

Nepenthe,

welcome to the dark side

As for that Nexus 120mm.. You could try the voltage splitter. That fan should start at 6V. I don't have a voltage splitter so I just spliced a 39 Ohm resistor in between (it should give slightly higher than 6V). They run at about 720 rpm with no sound

Be sure you've gotton rid of your fangrills though, at 720mm airflow is VERY low.

Nepenthe · Post by **Nepenthe** » Fri Nov 19, 2004 1:11 am

burcakb wrote:Jan,
Be sure you've gotton rid of your fangrills though, at 720mm airflow is VERY low.

Hehe, thought about that myself briefly, because I think some of the noise is generated by the air hitting the fangrills. But since I lack both the tools and skills for such a task, I'll just have to leave it be.

burcakb · Post by **burcakb** » Fri Nov 19, 2004 7:11 am

tinsnips are your friend

Still if you've got two nexus in pull-push (I forgot what your rig was like) it may still be enough at 6V.

For reference, I'm running such a system (but I did cut my fangrills) with a heavily undervolted CPU (6V 2xNexus 120, 3.5V on the Z7000) and my CPU temp at 100% FAH load is 45C at 25C ambient. Case is 35C max. perfectly safe