12v Trigger Relay For Cabinet Fan Controller? - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 7 Old 09-29-2012, 11:35 AM - Thread Starter
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Not sure if this is the right forum section for this ... mods, please move if necessary.

I currently have a credenza-type TV stand with a cabinet for A/V equipment. When I bought the credenza, I installed a modified back panel mounted with 4 x 120mm fans to provide air circulation inside the cabinet. I have the fans connected to a small fan controller with LCD temp display and thermal probe. The controller is currently plugged into a switched 120v outlet on the back of my digital cable box, so it switches on/off with the cable box.

Normally this works fine, but I think the controller might be pulling a little bit too much current from the cable box as occasionally when the fans switch on the box's HDMI output either blanks out or I get static snow. Turning the cable box off and on again fixes the problem.

I'm getting ready to buy an upper-mid-range A/V receiver, and I'm looking for one with a 12v trigger. I won't be using an outboard amplifier (at least not at the moment), but am hoping to be able to use the trigger with a relay to switch the fan controller on/off with the receiver. Instead of running the controller's power from the 120v output of the cable box, I would then be able to plug it directly into the wall outlet.

Is this possible? If so, can anyone recommend a relay that would be simple to hook up and could provide automatic on/off switching based on the 12v trigger output from the receiver?

I'm also open to other suggestions. This idea requires me to power on the receiver every time, and there may be occasions when I don't want or need to turn it on (maybe when I just want to use my TV's built-in speakers to keep volume low?) Admittedly, I can't think of any times now when that might happen, but I like to keep as many options open as possible.
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post #2 of 7 Old 09-29-2012, 01:09 PM
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There are quite a few options to control the dc fans.

1. 12 volt trigger power outlet. Xantech and Niles makes one. I have never used these.

xantech link:

Niles AC-3 Link: You may need more parts

2. A Smart Power strip. I have tried a couple of these over the years and have had very little consistent success controlling 12 volt fans.

3. Thermostat controlled 12 volt fans. This is a little cheaper and what I ended up using from Coolerguys:

Coolerguys Thermal Fan control:

Coolerguys 110 v AC to 5v dc:

A big quite fan from Noctura:

I hope this helps. The Xantech AC-1 looks pretty nice to.
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post #3 of 7 Old 09-29-2012, 02:00 PM - Thread Starter
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Thanks for the suggestions, Chrisc31759.

1. These trigger-controlled power outlets would fit the bill, if they weren't so expensive. The Xantech AC-1 is nearly $70 on Amazon, the Niles is even higher, over $100. I was hoping for a less-costly solution, but I'll keep these in mind.

2. The smart power strips, from what I understand, cut power completely when they "sense" that the components are in a stand-by mode. I guess this would work, but the receiver would need to be plugged into the same power strip to provide the "stand-by" status. Not sure how well these actually work in practice.

3. The thermostat-controlled unit from Coolerguys is exactly what I have now. I'm trying to use it without having to leave it on all the time, switched to turn on when the receiver is on. The power converter you linked to is a replacement for the one that I bought with the fan controller, and the Noctua fan is nice - but I've already for four nice 120mm Scythes mounted on the rear panel.

Out of the three, I think the trigger-controlled power outlets come closest to what I need. But, I'm still wondering if there's a simpler (and cheaper) relay that can take the 12v trigger from the receiver and switch the fan controller on/off, while the controller is plugged into a normal outlet.
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post #4 of 7 Old 09-29-2012, 11:41 PM
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Originally Posted by Matsutake View Post

3. The thermostat-controlled unit from Coolerguys is exactly what I have now. I'm trying to use it without having to leave it on all the time, switched to turn on when the receiver is on.

I assume that means you have a fixed-point thermostat unit, which is triggering below the standby / ambient temperature for that location?

Switch to an adjustable set point thermostat, dial it up so that it doesn't operate when everything is off:



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post #5 of 7 Old 09-30-2012, 07:05 PM
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I use the Nile 12v trigger for my amp to AVR and it works very well - and yes, I thought it was pricey too, but it does do the job easily. I also use the thermostat switch for my quad fan unit from Cooler Guys, but I do not think the fan turns on very often since the components are not enclosed.

There is another possibility that you may want to look into for more bang for the buck. Try researching power conditioner units from manufacturers like Furman, Panamax, UPC, Belkin and Monster. Some come with 12 v triggers and the unit will regulate your power, which should eliminate your power drop problem. Some also have battery back-up depending on your available budget.
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post #6 of 7 Old 11-26-2012, 10:20 PM
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The Niles comes up on eBay a lot and I've gotten a couple for $30 to $40 shipped. Just wait... There will be an auction that works for you. Otherwise you can use a relay board but those are $15 (2 relays though) plus everything to get them wired (a 12V source maybe, a box, outlets, lots of your time smile.gif, etc.)

Edit: AC-3 on Ebay.

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post #7 of 7 Old 08-14-2014, 11:23 AM
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Old topic but for those who were looking foward something to do the job, i´ve just set up one small relay and a 12v 2a power supply to run 2 fans (1 over my receiver and another one taking air out of my cabinet).

I´ve used a diagram i´ve found on google (where is written battery i´ve put the positive of the power supply)

It´s easy to find and cheap
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