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Quieter Fan Mod for Behringer EP2500

148K views 206 replies 86 participants last post by  KraftwerkTurbo 
#1 · (Edited)
Hi

The Behringer EP2500 has been getting more and more popular with IB subwoofer builders. (and other sub builders of course)

It offers plenty of power at a price that makes domestic stereo power amps seem foolishly expensive. For our subwoofer needs we aren't looking for "air", pinpoint imagery or crystal clear highs. Crossed over at around 80Hz you couldn't ask for a more affordable tractor to get those big cones moving. (and stopping just as quickly)

My opinion (shared by others) is that the original cooling fan is far too noisy. Niagara Falls or Victoria Falls don't even come close. (I'm joking of course but you get the picture) ;)

These amps are designed for live performances where they are probably screwed up to maximum volume into 2 Ohms and left that way until the gig ends.

For HT use and reproducing music at home these amplifier don't get nearly the same hard treatment. That means we can slow the rush of cooling air with quieter fan options.

The original fan is a standard PC size but runs on 24 Volts. I couldn't obtain a quiet Panaflow locally in 24 Volts so ordered a Papst from the Danish importer instead.

First you must remove the screws which hold the amplifier lid down. These are fixed along both sides near the top and along the back only at the very top. Don't start unscrewing the socket fixing screws further down at the back. You'll also have to remove the 4 screws which fix the lid down to the heatsink. Use a decent crosshead screwdriver to avoid damaging the screws. They are fitted quite tightly so you will ruin the screwheads with a poorly-fitting screwdriver!

Here are a some images to show what's involved in swapping the fan. The twisted red, black and white wires are the motor connection to the small PCB on the left. (seen from the front of the amp)

If you're past your guarantee period you could just snip the wires and use a connector block to join the new fan wires to the old ones wherever you consider convenient.

My amp is still under guarantee so I didn't want it to be blatantly obvious that I'd swapped fans.

Behringer do not approve of fan swaps. You can't really blame them considering the abuse they get in a live gig. The modded amp might be sold on with the quiet fan and nobody would be the wiser until the amp got fried. The unhappy new owner would then start badmouthing Behringer products. So keep your original Behringer fan in a safe place in case it's needed in the future.

The original fan wires have a little plug which is held to the PCB with hot glue. A scalpel or similarly sharp tool will release the glue and the plug can come free.

Careful examination of the tiny plug will show that it sits in a little holster which then sits on the pins protruding from the PCB. If you are lucky you may be able to do a plug swap in the original holster. My new Papst fan came with bare wires so I had to find a plug on another cooling fan which was compatible with the holster.

General view of Behringer EP2500 with arrow pointing to twisted fan motor wires.



Here's where the plug fits on the PCB pins.



The new silent Papst fan fitted. It blows air forward through the long, box-shaped heatsink.The fan sits in a thin, folded metal shell and is held by four long screws. The same screws hold the wire protective cage to keep fingers out of the fan blades.

Do not undo the four fan screws until you have the lid safely off the amp and can see inside.



I have monitored the amp temperature with a digital temperature probe and found a maximum of 4F above ambient after an hour of Metallica's Black Album at a steady 100dB on my RS meter. On action films the amp doesn't get enough exercise to warm up above ambient at all. In use a quite ticking can be heard if I stand close enough. A far cry from the roar of air from the original fan. Which could be heard form 12 feet away through the cones of my IB.

Others have mentioned using resistors to slow the original 24Volt fan. Perhaps somebody will chip in with their experiences using resistors and the values required. :)

UPDATE:

Here's a picture of the original Behringer fan. The size is 80 x 80 x 25mm.



Note that the wire is double insulated with a black sleeve over black and red. NOT the twisted R/B/W wires shown above.

It plugs into the small PCB on the left exactly as shown above.

Here's an image of the original plug within a plug. I had to buy a cheap fan with the same kind of plug because no local computer dealers sold the plug on its own.

 
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#121 · (Edited)
First, thanks to everyone who contributed to this thread. I love the internet. I found out about these amps on another forum and one of the members on that forum did a lot of bench testing comparing about 10 amps. He benched the amps at 2/4/8 ohms and regular and bridged. This amp is a FANTASTIC bargain compared to the Crown K2, Velodyne SC-1250 and a couple of others. The amps more than held its own and for under $300 it is a no brainer as a sub amp.

But, the fan is annoying. So thank you for sharing your experiences about replacing yours!

I do have a question regarding fans. I researched Papst fans and found the following 24volt 80x80x25 fans.

[Part] [V] [m³/h] [dB(A)] [Bel] [mm]
8414 NGL 24 DC 33 12 80 x 80 x 25
8414 NL 24 DC 33 17 80 x 80 x 25
8414 NGML 24 DC 45 19 80 x 80 x 25
8414 NML 24 DC 45 21 80 x 80 x 25
8414 NGM 24 DC 58 26 4,3 80 x 80 x 25
8414 NM 24 DC 58 27 4,4 80 x 80 x 25
8414 N 24 DC 69 32 4,7 80 x 80 x 25
8414 NG 24 DC 69 32 4,7 80 x 80 x 25
8414 NH 24 DC 79 37 5 80 x 80 x 25
8414 NH-221 24 DC 79 37 5 80 x 80 x 25

So, is the 8414 NGL ok, or does it not have a high enough CFM? I'd like to use it if it does. Otherwise, I think the 8414 NGML would work.

What do you think? Newark carries Papst fans! So, I just need to know if the 8414 NGL/NGML will work. They are a little more expensive, but with a higher flow and lower noise level the extra $10 wouldn't bother me over the next few years. :T

If neither Papst will work, I will go ahead and buy the NMB - FBA08A24L1A from Newark as suggested.

Thanks,
Mark
 
#122 ·
I am only familiar with the fan from Digi-Key NMB - FBA08A24L1A... Digi-Key part number P9739-ND.

If the manufacturers part number is the same, then certainly the fan should be the same.

I do not know the requirements needed... but I do know the fans I have ordered from Digi-Key are plenty quite for the four EP2500's I run that are located on an open shelf just ten feet in front of me. I have not had any over-heating issues thus far.
 
#124 ·
If my calculations are correct, the NMB does 40 m3/h at 21dBA. This is a proven solution so I would try to at least meet this.

The 8414 NGL is good for 33 m3/h at 12 dBA. Very quiet, but falls a little short of the NMB. It might work, but it would be a gamble.

The 8414 NGML is good for 45 m3/h at 19 dBA. More flow and less noise than the NMB...but more the twice the cost ($20 vs $8.68)...and I couldn't find a pic on Newark to confirm it is the correct shape.
 
#125 ·
I agree with your analysis. However, I'm a little confused when you wrote, "confirm it is the correct shape."

I have communicate with the folks at Papst, so I can get a pic a post it on here if you'd like, but don't fans come in one shape? Why would Papst manufacture a completely different fan shape in the same line? Again, I'l write them an email and let you guys know if it is a different shape.

That being said, I may pick up the 12 dBA b/c I don't want to hear the fan at all and I'm concerned that I'l hear it if it is at 19 dBA. Unless you guys think I have nothing to worry about a 19 dBA. The amp sits about 10' away from me.

I highly doubt I'm going to run amp that hard because it is used to drive very effiicient speakers on my Zu Definition Pro speakers. In fact, the amp only drives the woofer array and I can't use too much wattage for the woofers b/c my front array (MTM) is being driven by a Yamamoto A-08S that puts out a whopping 2 watts per channel.

Regards,
Mark
 
#126 ·
Dont worry about 19db. its inside the amp, in the back, in a rack away from you. 19db will not really be heard at all. I would be very surprised if you could hear it from 10 feet away. But you also have to think that the 12db one will be just about as good at cooling as in reality these amps dont get even warm even with spirited output. Mine does not get hot unless i am watching some reference material where i turn the sub up to its limits to show it off a bit. Either way youll be just fine.
 
#127 ·
I wrote to Papst asking for pics or a URL that contains pics so I can post them here. Then hopefully we can confirm the shape.

I don't mind spending $20 vs. $10 on a fan if it is going to *nearly* eliminate the fan noise. Nothing worse than hearing the fan as the volume in a song or piece of music diminishes.

Other than the fan noise, this amp has really impressed me. I hope this doesn't sound like boasting because I don't intend it to be. Rather it is a compliment. This amp is a part of my $35k stereo system and I seriously couldn't be more satisfied.

I'll post the pics or the URL as soon as I hear back from Papst.

Regards,
Mark
 
#129 ·
Here's another idea (from someone who is just about to order their own EP4000), what about a 12cm externally mounted 24v fan ?

I'm pretty sure you can get shroud that brings it back to 8cm, which you mount up against the back of the case where the internal fan is.

You gut an old 8cm fan or make your own extended shroud to ensure that you're sucking the air all the way through the 'tunnel'.

Larger fans tend to be always a bit quieter than a smaller fan, and also move more air than a smaller fan can.

You can also choose how you supply power to the externally mounted fan, either by through the existing fan slot then through a small hole in the shroud, or by a plugpack/wallwart, in which case you go for a 12v fan with a 9v or 12v plugpack.

Since all of this is out of reach of prying kid fingers, being at the back of your cabinet or rack, then I can't really see any safety issues.

With this idea of externally powered, you have the options of many different 12v fans, both 8cm and 12cm with a shroud, which should be a whole lot cheaper than 24v fans.

:)
 
#134 ·
I finally got my PAPST fan and did the mod. I simply cut the wires and soldered them and wrapped the soldering with "shrinking" plastic.

The new fan is dead quiet. I mean it's not even audible. I had to doublecheck it was running as it was so quiet. I can feel the air move out front though so there is circulation. Watching Queen live at montreal on blu ray at MV-8 the amp doesn't even get warm enough that I care about it. I should add I also have installed a fan inside my rack.

Button line is, the fan mod is, in my opinion, a must if the amp is placed in a living space. It's well worth it and if I get a second EP2500 I'm so confident in this solution that I will place right on top of the one I have now, inside the rack and fire away at MV-5 all day long :)
 
#143 ·
I have 2 of those Enermax fans in mine, wired in series since they're 12v fans. Both at the rear of the heat sink, blowing hot air out. One fan, once inside the case, does not move much air so I'm glad I bought two.

I've had my fans shutoff on me once when I was listening to an hour long bass heavy dance mix. The amp didn't get hot enough to thermally shut down, but it was still hot. I have a theory that the fans got too hot having the hot air blow across them, causing them to shut down for some reason, but since I've not been able to repeat the scenario and do tests/rule things out, I can't prove anything.

So to answer your question, I bet the Enermax will be quieter (it's real quiet), but it's also not a 24v fan. And by itself, it won't move much air.
 
#138 ·
A quick update that may help, especially those looking for UK fan suppliers.

I purchased my 12dB fan here: http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=2991403

It works fine and is completely silent in your hand but obviously vibrates slightly as it does buzz a little when installed. This is still a lot quieter than the stock fan and still provides adequate airflow IMO.

I decided to keep the fan facing forward as I have always had better results 'pushing' air through heatsinks than I have 'pulling'.

As a final mod to reduce the buzzing I was getting, I used 4 rubber washers left over from some old PC fans to isolate the fan from the chassis. You can still hear it with your ear close but it is much better.

The photo shows the type of washers I used, they actually work better if you don't tighten the screws too much, I actually loosened them off a fair bit after taking that photo.



Cheers,

Adam :shh:
 
#139 ·
As a final mod to reduce the buzzing I was getting, I used 4 rubber washers left over from some old PC fans to isolate the fan from the chassis. You can still hear it with your ear close but it is much better.

The photo shows the type of washers I used, they actually work better if you don't tighten the screws too much, I actually loosened them off a fair bit after taking that photo.

Adam :shh:
Hi Adam

The rubber washers sound like a good idea. :T

I get an irritating metallic buzz from my Papst fan despite the low airflow noise level.

Thanks

Chris
 
#144 ·
Re: Quieter fan mod for Behringer EP2500

I have the same exact annoying problem with my QSC rmx 2450. That amp has a real warm sound but that fan THAT FAN!!!! it drives me nuts! it is noisy and it is terrible. And it is also 24 volts. That amp as I said before looks so much like my QSC inside. the only difference inside is the boards in the QSC are blue color and bigger. I need a new fan.
 
#148 ·
Okay so I ended up ordering a fan from digikey since they had them in stock. I got a model # FBA08A24L
24v. But I encountered a problem when I hooked it up. When I did a preliminary check after soldering the connections the fan worked. But after I put the shrink tube over each wire I checked it again (prior to putting the cover back on) the fan did not work. I checked all the connections and the fan does not work. So I disconnected it and reattached the original and that one works fine.
So did I get a bum fan?? or did I order the incorrect one?? The new one spins freely and does not bind. The only difference I can find is that the original one says 0.25A and the new one says 0.09A. Could that be the issue?
I shouldn't even be messing with any of this since I have h1n1 right now but I was sick of being stuck in the house for 3 days..... probably should have left it for later.
 
#149 ·
Great thread guys. I know - and old too. But I had to post to let you know because of this thread I can now let my Behringer EP1500 in the house! I installed the P9739-ND from Digi-Key following the very easy directions here.

I know why Behringer makes the fan so energetic -- they expect these amps to be used in a torturous environment - but you'd think they would market an amp with a sub letter on it like with an 'H' to let those buying it that it has a quiet fan inside so we don't need to open it up and void the warranty. Put a 'P' behind the model number and viola! its a pro amp with special high velocity cooling - with special noise effects all it's own!

Anyways - kudos to you guys who make the discoveries so people like myself can chug on without having to reinvent things.

Ya gotta love the internet. 20 years ago I'd never buy an amp like this.
 
#150 ·
G,day all. Like so many I have found the 2400 to be an excellent sub amp,yet the roar of the fan was unbearable. The cost of an suitable 'low noise' after-market fan was untenable,combined with a lack of real estate to house this and other boxes,led to an easy decision. Using a brick bolster and hammer,I knocked an opening through to an adjacent room,and housed the amp there.Problem solved! Yet,in the still of the night,I can hear the (distant) fan noise beyond a solid brick wall. Cheers, Mike.
 
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