I'm trying to come up with a way to get improved airflow to my amp which runs hot (she's old but still pushing hard). I'm thinking that some 40 mm computer fans would work well.

I've got on '04 Chevy Colorado Ext Cab and the amp is on the floorboard where one of the toolboxes/fold down seats are located. I'm going to build a small frame to hold my amp in place and be able to use a rear fold down seat. I mention this, because I can mount several fans around this frame. I'm thinking that a few fans on each side would help out.

Any thoughts on this? What I'm not sure about yet is how to power them...

8/30/2009 12:58:41 AM

just use 2 12V fans, one that pushes and the other that pulls the air on the opposing side

8/30/2009 1:02:07 AM

They're 12 volt usually, so it's not a big deal on where to get your power from. I'd put a small relay in with the trigger on your amp on lead from your head unit. Your best bet is to build a shroud for your amp and use two fans on the same end in a draw-through arrangement. Actually, it doesn't matter the arrangement, whether push or pull, and in retrospect, a push-style would probably be better. Just elevate your amp between 1/2 and 1 inch off the floor if you can using standoffs.

Better yet would be to use two pieces of c-channel extruded aluminum as they will help with heat sinking.

A single 80 mm fan will push a lot more air, though.

Which amp in particular do you have? I have one of the original Fosgate Punch 45 HDs...and a cooling shroud to go with it.

8/30/2009 1:06:10 AM

thanks. can you elaborate more on how to wire all this?

best google result so far: http://www.bcae1.com/coolfans.htm but I'm not fully clear on what they're saying as far as connecting them to the remote.

^An old jensen 400 watt-4 channel (LXA400)

I'm stuck to using 40 mm or 50 mm as I only have about 75 mm to work with

[Edited on August 30, 2009 at 1:21 AM. Reason : .]

8/30/2009 1:08:27 AM

Ok, I think I have this correct now, double check me please.

Splice off the amp's power wire to terminal 87 (match power wire gauge)
Splice off the remote to terminal 86 (match remote wire gauge)
Run wire from terminal 30 to fan + (match power wire gauge)
Run fan - to chassis/ground (match power wire gauge)
Add a fuse between terminal 30 and the fan, according the fans pull ~ 5 amps maybe?

[Edited on August 30, 2009 at 1:39 AM. Reason : .]

the fans I'm seeing appear to have 3 or 4 pin connections...?

[Edited on August 30, 2009 at 1:44 AM. Reason : .]

8/30/2009 1:38:21 AM

I would use 1 or 2 120mm fans so they're quiet. Hopefully this pic comes out

       /+---------------+\
     /  |                      |  \ 
  [F]  |                      |    [F]
  |A|  |       AMP         |    |A|                              +--------------------+
  [N]  |                      |    [N]                               |           Amp           |
    \    +---------------+   /                                  +--------------------+
                Baffling                                               || || || || || || || || 
     \---------------------/

8/30/2009 3:32:47 AM

pins 86 and 85 are the coil in the relay. So one of those has to be the trigger, whether it's power or ground. Then the opposite polarity of the trigger should be put on the other pin. So if you are triggering the relay with +12V on pin 86, ground pin 85.

Then 87 and 30 are normally open contacts. So when you trigger the coil (power and ground on pins 85 and 86), the circuit closes. Power or ground would then flow from pin 87 to pin 30 or vice versa. So in your case the power source could be hooked to pin 87 and then pin 30 could be hooked to the fan(s).

8/30/2009 4:24:36 AM

^^,^thanks. ^^is roughly what I'm planning to do. I'm not sure on my ability to raise my amp - I'll have to measure some things.

^thanks, but I"m stuck with 40-50 mm fans since I only have 3 inches to work with. and your explanation was helpful, and it seems to me that it matches this:

Splice off the amp's power wire to terminal 87 (match power wire gauge)
Splice off the remote to terminal 86 (match remote wire gauge)
Run wire from terminal 30 to fan + (match power wire gauge)
Run fan - to chassis/ground (match power wire gauge)
Add a fuse between terminal 30 and the fan, according the fans pull ~ 5 amps maybe?
Run 85 to ground.

8/30/2009 11:11:29 AM

also, what about the fans wires - I've only seen 3/4 pin; which wires to I need to splice into? or does anyone carry amp fans with just +/- fans

8/30/2009 11:50:23 AM

What colors are the wires?

8/30/2009 12:03:42 PM

yellow = 12v higher then blk
red = 5v higher then blk


For PC fans.

8/30/2009 12:20:26 PM

I have a suggestion, ditch the Jensen for an amp that will run cooler putting out the same amount of power.

I have 2 PPI's buried under my back seats in my Jeep (ie, an oven) and about the only time I've ever had one turn off is when I've started blasting bass as soon as I get in while my ride has been baking in 100 degree sun all day.

8/30/2009 12:23:57 PM

just thinking about it... if you want to extend the life of the fans or reduce fan noise, you could even do a two-speed deal if you want to. You would need an additional 5 pin relay, a resistor, and whatever you would like to use to trigger it from low speed to high speed (temperature probe, manual switch, timer, whatever). 87a is the normally closed contact on a 5 pin relay (the one in the middle). That one is connected to pin 30 unless you engage the coil, which turns off pin 87a and turns on pin 87.



A lot of multi-speed engine cooling fan systems are triggered this way. But they usually have either 2 relays (2 speed fan systems) or 4 relays (3 speed), depending on the design of the fans etc.

[Edited on August 30, 2009 at 12:26 PM. Reason : yeah Jensen is turd. none of this should be necessary anyway, it's just something to talk about]

8/30/2009 12:25:29 PM

Quote :

"I have a suggestion, ditch the Jensen for an amp that will run cooler putting out the same amount of power. I have 2 PPI's buried under my back seats in my Jeep (ie, an oven) and about the only time I've ever had one turn off is when I've started blasting bass as soon as I get in while my ride has been baking in 100 degree sun all day."

$20 repair versus $100's on a new amp for a system that I've put together for about $100.

I'm saving up to get a good & working system. until then I'll keep cheaply repairing my cheap system.


^I think a simple one speed setup would do fine/trying to keep things simple.

^^^^wires are red, yellow, and black

Quote :

"yellow = 12v higher then blk red = 5v higher then blk"

so what does this mean for wiring this up?



[Edited on August 30, 2009 at 12:54 PM. Reason : .]

8/30/2009 12:49:51 PM

sounds like a project that can get more pricey since you have no idea how many fans you'll need. i'm with fail boat... you can spend 20$ and countless time "repairing " your system or you could sell the jensen and buy something better used.

8/30/2009 2:20:36 PM

I'm only going to do 2 or 4 fans and I'm pretty sure that will do fine; if not oh well. The main problem is that the place where I have/need the amp doesn't get good airflow. So even with a new amp, I'd probably need fans for airflow. And this amp isn't worth anything and I'm not buying a new amp until I have enough money to redo the entire set up. I'd rather do everything for the new system at one time for install ease and because prices and products are always changing.

That being said, I think I'll just order a few amp fans since those don't give me as many wiring issues (unless I can find a case fan with 2 wires) and use the wiring stated above.

Thanks for the input.

http://www.geeks.com/details.asp?invtid=40MM-CASE-FAN-2PIN&cat=CAS

[Edited on August 30, 2009 at 3:16 PM. Reason : .]

8/30/2009 3:07:09 PM

I know we're not going to change your mind, but if you get a better amp now, one that you'll have in your final system, you can begin enjoying it now.

Quote :

"So even with a new amp, I'd probably need fans for airflow."

Did you read what I wrote? I have amps buried in my seats. So, I don't even have the benefit of being able to radiate the heat to free air and I don't have problems.

Quote :

"I'd rather do everything for the new system at one time for install ease "

An amp change should take 10 minutes tops.

Quote :

"because prices and products are always changing"

Not so much. The products that have always been solid are more or less at the prices they are going to be if they are used.

8/30/2009 4:17:57 PM

Thanks for the input, but I don't have the money for a new amp right now, I'm not sure what my needs will be for my next system, and what I have works, I'd just like to provide airflow/cool it down some.

As for your preferences/system, that's fine. If what you have works and you are fine with it, then so be it. I'd prefer to have increased airflow over mine and I don't think spending $20 and one hour of work is ridiculous.

I know how long it takes to exchange amps. I just don't want to buy an amp now and have to get another one in the next year.

Prices and products do change. One pioneer I was considering dropped $200 from its release price over a period of about 3-4 months.

8/30/2009 4:54:52 PM

make sure you use a brushless fan otherwise you will be introducing noise into the audio system. I recommend this fan. http://www.hifisoundconnection.com/Shop/Control/Product/fp/vpid/1331966/vpcsid/0/SFV/30046

8/31/2009 1:14:35 PM

ok, thanks. I'm not too sure about getting a stinger though. I had one of their line level converters and it was complete crap...

^ what would be wrong with using a case fan such as http://www.geeks.com/details.asp?invtid=40MM-CASE-FAN-2PIN&cat=CAS compared to the one you posted (other than cfm rating)?

[Edited on August 31, 2009 at 4:26 PM. Reason : .]

8/31/2009 4:22:50 PM

Every computer case fan made is of the brushless variety. It doesn't fucking matter.

8/31/2009 4:37:02 PM

dispite you avoiding the obvious answer to your problems i guess i'll still help.

don't do a 40 mm fan. for it to move a amount a reasonable amount of air it has to spin FAST and running 4 of them would produce a super annoying whine. go with a 60 mm or 70mm if you can. they'll move a ton more air and be a lot less noisy.

[Edited on August 31, 2009 at 7:01 PM. Reason : .]

8/31/2009 6:59:04 PM

Honestly, I think a single 120mm just laid on top of the fins should be a big step up over what you have, no need to make any tunnels or anything. Having said that, we'll be entering some cooler weather in another month or so. Is the amp turning off from overheating or something?

8/31/2009 9:45:00 PM

is the "remote" or amp turn on wire ( i think it is commonly the color blue) active high or low and at what voltage?

8/31/2009 9:49:40 PM

^^the problem with that is that a fold down seat comes over the top of it (it rests on a wood frame around the amp). it hasn't turned off yet, but it gets so hot I can barely even touch it (hotter than ever before). I'm just trying to salvage any life that's left in it. And that being said, I haven't run it hard for long since adding some speakers, so it may very well overheat under those circumstances.

^I have no clue on that actually. It is on 12v power, blue wire, on something like a 15 amp fuse.

8/31/2009 10:08:18 PM

You don't need a complex setup. One or two 12v fans blowing across the top of the amp should give more than enough convection, especially if it's 2 or 3 inches tall or more to fit vertically underneath the seat. Most that size would run approx 100mA to 500mA. Personally I would run the +12V/hot wire to the accesory fuse box in the cab. Find a higher amperage fuse (15 or 20, 2.5 or 5 is too low and will blow the fuse for the circuit) that is turned into a hot circuit whenever your ignition is switched to accessories or run/on so your fan doesn't draw down the battery or run whenever your audio system isn't on either. Use a multimeter to check for voltage at those fuse terminals to find that out. Run the ground to ground (dur). You should be able to lay down the hot wire underneath the carpet and/or trim and ground out to the seat brackets.

[Edited on August 31, 2009 at 10:17 PM. Reason : .]

8/31/2009 10:16:32 PM

Quote :

"And that being said, I haven't run it hard for long since adding some speakers"

What speakers did you add? How did you wire them? Are you running the amp at 2ohms now? My guess is the Jensen is not stable at 2 ohms and thats why it is heating up.

Quote :

"Every computer case fan made is of the brushless variety. It doesn't fucking matter."

Didnt know that.

9/1/2009 8:50:38 AM

Quote :

"You don't need a complex setup. One or two 12v fans blowing across the top of the amp should give more than enough convection, especially if it's 2 or 3 inches tall or more to fit vertically underneath the seat. Most that size would run approx 100mA to 500mA. Personally I would run the +12V/hot wire to the accesory fuse box in the cab. Find a higher amperage fuse (15 or 20, 2.5 or 5 is too low and will blow the fuse for the circuit) that is turned into a hot circuit whenever your ignition is switched to accessories or run/on so your fan doesn't draw down the battery or run whenever your audio system isn't on either. Use a multimeter to check for voltage at those fuse terminals to find that out. Run the ground to ground (dur). You should be able to lay down the hot wire underneath the carpet and/or trim and ground out to the seat brackets."

Oddly, you said he doesn't need a complex setup, then suggested something more complex than tapping off the remote lead that is already run to the amp.

Quinn, the remote turn on is active high. I've never measured it, so it's possible it just floats with the battery voltage. I can't imagine HU makers go through the trouble of regulating it. As soon as I get out of my PJs and decide to be productive today, I'll go measure it.

9/1/2009 8:59:27 AM

^^ added 2 6 x9s (for a total of 4) and an 8" sub 6x9s are wired in series and bridged

though, I have had it wired with 4 6x9s only, bridged in parallel and the amp still got damn hot - as in , can hardy touch it hot.

[Edited on September 1, 2009 at 9:04 AM. Reason : .]

[Edited on September 1, 2009 at 9:09 AM. Reason : .]

9/1/2009 9:02:07 AM

let me clarify ^ just in case:

2 6x9s bridged on C+/D- in series
2 6x9s bridged on D+/C- in series
1 8" sub bridged on A+/B-

9/1/2009 9:35:50 AM

Now I see why your amp is so hot. The bridged channels are acting like they see a 2 ohm load with this configuration. I understand the amp can do it (3 channel mode) but I'll be surprised if fans help much. If this is the case, again, rather than spending $20 on a fan setup, just get another small amp to power the other 6x9s in the back

http://cgi.ebay.com/SONY-CAR-POWER-AMPLIFIER-XM-4520-2-CHANNEL-MOSFET-NICE_W0QQitemZ360183330862QQcmdZViewItemQQptZCar_Amplifiers?hash=item53dc99782e&_trksid=p3286.c0.m14

9/1/2009 12:52:49 PM

yeah your wiring is wrong. Channels C and D should only have one way of bridging them. Either C+ and D- or D+ and C- not both.

Assuming you have 4 ohm speakers, the best way (coolest way) to run them is...

2 6x9's running in series to channel C. That would give Channel C a 8 ohm load.

2 6x9's running in series to channel D. That would give Channel D a 8 ohm load.

This setup will still give you stereo separation. If you dont care about that, then run both 8 ohm loads parallel and bridge them to channels C and D. This will give you a mono 4 ohm load. Check the amp and see which + and which - to use when bridging. One is usually correct and one is not. It should be drawn out on there.

Leave the sub as it is.

It wont be as loud (the 8ohm stereo option) but also wont try and draw more current than your amp can deliver. Also an undersized power or ground cable (or a bad ground) can cause it to overheat.

9/1/2009 4:22:18 PM

No, apparently his amp is spec to do 3 channel operation and I think he has it wired right. It just means it's extracting every last ounce of power out of the transistors and the amp is running at its limit.

9/1/2009 6:01:16 PM

if the amp hasn't turned off due to heat yet and your saving for new equipment i would scrap your whole fan idea. amps are designed to run until they hit a certain temp at which they go into protect , if it hasn't done that your should be fine until you upgrade. i've orion amps for years that ran hot enough to scramble eggs never shut off or missed a beat. unless you don't have the appropriate wire awg then it sounds like the sink is just doing it's job.

9/1/2009 6:30:39 PM

^^Well in response to being more complex, I guess for someone who hasn't tried to do it before it can be a pita. I was refering moreso to the likes of multispeed fan control and building wind tunnels. It's not hard by any means.

^True

[Edited on September 1, 2009 at 6:34 PM. Reason : ^'s]

9/1/2009 6:32:34 PM

thanks for the latest responses. according to the install manual, the wiring I have set up is correct, except for placing them in series - there's no information on that. I'll keep playing around with it.

as for the fans, since many of you seem to think they'll do no good, I'll scrap that idea for now. I've drilled holes in the wood frame around the amp and I can leave the fold down seat up when it's not in use.

I was just worried about excessive heat for long periods of time on such an old amp (i'm fairly certain its about 10 years old) even if it didn't go into protect mode.

thanks again

9/1/2009 8:46:44 PM

HHR Fan ~$60@RockAuto

9/1/2009 11:01:45 PM

Quote :

"^^Well in response to being more complex, I guess for someone who hasn't tried to do it before it can be a pita. I was refering moreso to the likes of multispeed fan control and building wind tunnels. It's not hard by any means."

It's not that your suggestion is hard, it's unnecessary. You're advocating tapping off the fuse box and running wires under carpet and such when he already has a switch available at the amp (the remote turn on), a ready power source (the 12v line coming in), and a ground (can use the amp terminal if lazy, otherwise the chassis).

Your solution trades the relay for having to get into the fuse box and pulling up carpet and trim to run the wires.

Quote :

"I was just worried about excessive heat for long periods of time on such an old amp (i'm fairly certain its about 10 years old) even if it didn't go into protect mode."

For sure, running the amp at around it's thermal limit will result in a reduced lifespan. But no one really knows when it will die as no amp maker that I am aware of does any sort of a test like this.

9/2/2009 8:28:56 AM

whatever floats your boat i guess

10/15/2009 2:50:16 PM