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PostPosted: Mon Mar 13, 2017 2:00 pm 
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Joined: Fri Nov 04, 2016 12:53 pm
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Location: Surrey, BC, CA
I'm using this power amp to power my two subs. It does the job just fine but the fan noise can be annoying. I can't really hear it when playing music, even at lower volumes but when a song fades out/in, you are greeted with an audible humming.

I'v heard of fan mods and was wondering if this is an option for this thing. I was wondering if I could just turn off the fan. I don't really drive this thing hard and only listen to music for an hour or two every now and then at low to moderate volume levels.

Any suggestions or alternatives?

Thanks


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PostPosted: Mon Mar 13, 2017 2:32 pm 
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Joined: Wed Jul 09, 2014 2:06 am
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Location: toronto, ON, CA
I had the same amplifier years ago.
It drove 2 18 inch subs and crossed over to 2 JBL full range speakers.
The fan was always noticeable at lower volumes.
the reason the fan ran all the time it was designed for PA systems.
You could open it up and put in switch to turn off the fan.
When you run it loud you could turn it on.
I had another amp that I put in a pot to vary the voltage to the fan.
That would allow you to control the fan speed.


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PostPosted: Mon Mar 13, 2017 3:02 pm 
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Joined: Sat Feb 23, 2013 10:41 am
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Location: Burlington, ON, CA
Disconnect the fan, remove the cover, and put a cage over it.

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PostPosted: Mon Mar 13, 2017 3:55 pm 
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Joined: Sat Jul 04, 2009 6:08 pm
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Location: Montreal, QC, CA
Its a commercial PA amp meant to be used in high powered live venues where the ambient noise drowns out the fan noise. The fans are there to keep temperatures under control and prevent the amp from blowing up from overheating. Either put the amp in an adjoining room and run appropriate cabling, modify the amp with thermostatic control for the fans or learn to live with the noise.


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PostPosted: Mon Mar 13, 2017 4:03 pm 
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Joined: Fri Jul 01, 2005 1:56 pm
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Location: near PETERBOROUGH, ON, CA
Stick this inline with the fan wiring.......
http://www.ebay.ca/itm/KSD301-40-C-104- ... Swo3pWcocA

Locate the sensor close to the hotest spot.

This is not expert/CSA advice!


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PostPosted: Mon Mar 13, 2017 4:20 pm 
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Joined: Wed Feb 27, 2013 8:43 am
Posts: 1177
Location: Stratford, ON, CA
Hi,

Che wrote: 'Disconnect the fan, remove the cover, and put a cage over it. '

Exactly right. The fan is there because the style in PA work is to stack the amps in racks, one on top of the other, maybe six or eight deep. The fan drives the cooler air over the heat sinks because there is no way the hot air can get away (by rising) fast enough without heating the amp above it and so on up the rack ladder. For your application, getting the lid off and ensuring there is about a foot of clear air above the amp will suffice. Usually there is some thermal protection in PA amps so worst case will be it shuts down and then resets. Generally PA amps in PA applications are run full throttle, with the gain knob at maximum. But for domestic use, you can cut the gain knob to a lower power output (say a 2 pm setting) and that will ensure that overheating will never happen. Just unplug the fan, and let the hot air rise.

Cheers,
David Neice

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PostPosted: Mon Mar 13, 2017 4:32 pm 
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Joined: Thu Nov 29, 2007 4:20 pm
Posts: 36
Location: saskatoon, SK, CA
I own a ap4040 and a ap4020, have for years. The fan died in my 4040 called long mcquad see what to do. I was told not to worry about the fan. I could run the amp just fine without it. I ordered a new one,It made no diffrence with fan or with out.


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PostPosted: Mon Mar 13, 2017 4:58 pm 
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Joined: Fri Feb 13, 2009 4:51 am
Posts: 244
Location: kanata, ON, CA
Some really good advice here. But whenever I'm confused, I go directly to the manufacturer, where the real experts are.

They happen to be in Pickering ON.

http://yorkville.com/contact


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PostPosted: Mon Mar 13, 2017 5:09 pm 
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Joined: Thu Nov 25, 2004 4:52 pm
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Location: Montreal, QC, CA
The fan is there for a reason, do not disconnect it under any circumstance. Some power amplifiers will go into thermal shut down even in a quiescent state without one.
Being a Pro amp means that the fan has been spinning for a while and is likely in need of a cleaning, lubrication or in a worst case replacement due to bearing wear and pending failure. Those are the most common contributors to fan noise, fan grilles and finger protectors cause turbulence and too contribute to noise.

You have many choices available to you without running the risk of overheating. You should first try servicing the fan but if it is not salvageable, replace it.
Although modern fans run quietly, you may not need the full CFM cooling spec in your application so you may insert a dropping resistor to lower RPMs. Depending on your level of OCD, a shunting thermal switch can be placed in parallel with the resistor. Since many fan speeds are thermostatically controlled, you will still benefit from high speeds when the duty is called for.
I`ve had success in using 220 volt fans in place of 110v originals. Another cooling solution I`ve found to be most effective with convection designs is to place a laptop cooler underneath it.


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PostPosted: Mon Mar 13, 2017 9:27 pm 
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Joined: Fri Nov 04, 2016 12:53 pm
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Location: Surrey, BC, CA
Cool. Thanks for all the tips. I think I'll open it up tomorrow and clean it up first. Maybe that will make it more tolerable.

I'll tinker around without it and see what happens.

I'll give yorkville a call as well.

Thanks!


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PostPosted: Mon Mar 13, 2017 11:58 pm 
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Location: Surrey, BC, CA
Gave it a good cleaning. Dust bunnies took over everything in there. But....the noise persists. I found the model number for that fan and read up on the specs. It creates 43dBA of noise as per the specifications.

It is easy easy to disconnect and I gave it a try. As predicted, it killed the noise. I'm just going to leave it disassembled and not use it until I hear back from yorkville, Hopefully they tell me that "undertenposts" is right.

Another question, a few people suggested I make a cage for the top. Ummmm....how exactly do I do this? Seems like something I would give a try.

After looking into this a bit further, I think with some splicing, I should be able to use a regular computer fan. I'm not an electronics wizard and was hoping to get some clarification with what I can use.

Here are specs of the fan that it comes with:
Model: Ebmpapst 12v 80mm
Power rating: 4W
CFM: 39.4
Operating Voltage: 6-15V DC

I found another fan that has half the fan noise with similar specs. See below:
Power Rating: 2.88w (maximum speed setting)
CFM: 75 (maximum setting)
Operating Voltage: 10.2V to 13.8V

Would something like this work?

I also noticed that there are some USB powered 80mm fans out there that I can use without touching any of the internals of the power amp. That might be the easiest option. I would just have to sneak the USB cable out of the back somewhere.


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PostPosted: Tue Mar 14, 2017 5:18 am 
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Location: Montreal, QC, CA
By cage, what most people are referring to is a electrically well insulated, perforated metal top cover and/or bottom cover. Perforated metal sheets are readily available at REAL hardware stores and lumber yards and will require a bit of DIY metalsmithing skills and the existing top cover as a template. You want a pattern that doesn't restrict air flow but which prevents larger dust and foreign objects from getting in.Just make sure that the inside of the perforated metal is well painted/insulated so it doesn't accidentally short anything out.

Attachment:
Perforated stainless steel sheet templates (20).jpg
Perforated stainless steel sheet templates (20).jpg [ 117.1 KiB | Viewed 1134 times ]


As for replacement fans, as long as the size, voltage, mounting holes, connector and CFM ratings are within tolerance, any suitable fan should do. Just avoid going overboard on the CFM rating +/-25% should work just fine; doubling it will probably result in increased airflow noise.


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PostPosted: Tue Mar 14, 2017 12:56 pm 
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Joined: Fri Nov 04, 2016 12:53 pm
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Location: Surrey, BC, CA
Ok so here's what I did:

I know this thing has thermal protection so I thought I'd see how long I can use it with no fan. I placed the cover back on. I played at a volume I normally do (maybe a bit higher just for testing purposes) and it's still going strong 2 hours later.

That being said, this can't be good long term so I did buy a USB fan that will do the trick (I think). it is a little smaller but specs indicate it is quite a bit quieter.

That's it. Done with this project.

Thanks for all the help!


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