Alchemy LED strips + CW611

umfaddi · November 30, 2015

Hello all and kindly thank you for stumbling upon this thread.

I have just bought myself two Alchemy 2.0 30cm LED strips and would like to connect them to my Lamptron CW611.

Now, the problem is the connectivity off the LED strips.

^ This is what I got in the Alchemy box.

^ This is what I use to connect fans to the CW611, basically 3-pin fan extensions with male at the ends.

What I want to do is connect the 2 LED strips through an Akasa fan splitter and use one channel to control the brightness. Now, how do I connect the two of them together seeing how the adapters I bought the Noctua NA-SAC1 have males at the end as well (obviously very stupid of me for not checking before hand).

I am writing because I am pretty sure I am missing on something really obvious and any help would be greatly appreciated. Many thanks!

Naeaes · November 30, 2015

Let me shoot your dreams full of holes right here and now! Really, I'm sorry to say this but I don't think this'll work.

LED's need certain voltage to light up. There are leds for 3V, 5V, 7V, 12V and so on. But they're different models and you can't light up a 12V LED using just 3 Volts and so on. It's not just dimmer, it won't light up at all. Also if you plug a 3V LED into 12V power supply, it'll blow. But that's not the point. The fact that a minimum level of voltage is required, is.

The mechanism of slowing down the fans that panel uses is very basically lowering the voltage. Give a 12V fan just 10 volts and it'll spin slower. Give it 7 Volts and i'll spin even slower. At some point the voltage gets too low for the fan to overcome it's own friction and the air resistance so it'll no longer spin. Again, not the point. The fact that fans can be 'dimmed', if you will, by lowering the voltage, is.

The fact that the adapter for the LED strip takes it's power from the +12V pins on the Molex connector, tells me, you're dealing with 12V LEDs.

It is possible to dim an LED without lowering it's operating voltage. The method is called PWM (Pulse Width Modulation). Basically the same 12V is retained constant but it's switched on and off very rapidly. The LED won't shut down instantly, instead it dims slowly for a while (order of microseconds, I believe) while no voltage is applied and it also won't go to full strength instantly once it gets the power. So by varying the length of the power-on and power-off periods, an LED can be dimmed.

It's entirely possible for a fan controller to have a +12V PWM function but Lamptron CW611 doesn't have one. I can tell by the fact that it doesn't have the 4-pin fan connectors which is a requirement for PWM fans to operate. Not all PWM are the same though. I don't actually know what the pulse widths are for fans so I can't even guess how an LED strip would function when plugged to a PWM fan controller. In the risk of blowing stuff up, I'm not brave enough to plug my own LED strip to a CPU fan header to test it.

Tl;Dr: You should forget about this and get a dedicated PWM-enabled LED controller instead. NZXT Hue for example. It's also possible to make your own from something like an Adruino.

W-L · November 30, 2015

-SNIP-

Welcome to the Forums!

As Naeaes said using DC voltage control to vary the brightness of 12V LED's while possible is a very small limited range but can be used to dim LED's while not ideal.

The Bitfenix alchemy use SMD5050 LED's in a 3 line array with resistor to give a forward voltage of 12V, where they can theoretically drop down to approx 8V to be voltage dimmed. The main thing is for the LED strips and your fan controller is I would ensure you have the correct connections to enable this to 3 pin fan and that each header has the capability to provide enough amps to not overload the controller.

umfaddi · November 30, 2015

Thank you very much for both of your answers, looks like I will have to resort on the default brightness of the LEDs.

musonius · October 2, 2016

sorry for necroposting

actually lamptron cw611 works with led strips but not RGB and 12V only. I use it with my 9 coolers (3 in 3 packs) and 2 led strips. so it took 3 channels for coolers and 2 channels for led.

I use phobya uv-led strips, 1 big HD 240cm for one channel and 2 small HD 30cm connected to Y-wire for the other channel.

works perfectly. just put the channel used for strips to manual and choose flow meter. it'll give constant 12V output. no blinking, no turn off/on problem, no problems at all.

I dont have onecolored strips (only RGB and hue and hue+ controllers), but it seems to work fine with them too.