Quieter fan mod for Behringer EP2500

**Chrisbee** · **02-24-07, 09:23 AM**

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.

**FlashJim** · **02-24-07, 10:09 AM**

Timely post for me. I just ordered an EP2500. Thanks for the post!

Do you have a link for the fan?

**Chrisbee** · **02-24-07, 10:31 AM**

Quote:

FlashJim wrote:

Timely post for me. I just ordered an EP2500. Thanks for the post!

Do you have a link for the fan?

Thanks, Jim.

As I live in Denmark I doubt a link would be of much use to you.

It would be a matter of searching for a supplier of quiet 24V fans in the USA.

Examples are: Panaflo FBA08A24L1A, 24V, 80x25.5, 21dB or 24 V Papst TYP8414L or 8414NGL (the Papst model difference lies in the bearing type)

No doubt others more local to you can help here.

It has been suggested that placing an LED in series with a quiet new fan will check that it is always working. As they are usually so quiet after modification this might be a good idea. (But only if you remember to monitor the LED)

Regards

Chrisbee

**Exocer** · **02-24-07, 11:17 AM**

Thanks for the contribution

Does this mod also apply to the Ep1500?

**Chrisbee** · **02-24-07, 11:22 AM**

My guess would be yes but I have no experience with the EP1500 at all.

**Exocer** · **02-24-07, 01:55 PM**

Ah. I don't mind giving it a shot with the Ep1500 one of these days to let you guys know if it does work.

**Chrisbee** · **02-24-07, 03:03 PM**

I just had an awful thought!

The twisted cooling fan wiring I showed in the images above is nothing to do with the EP2500!
It came from a cheap PC fan I bought just for the matching plug.

I shall have to find the original Behringer fan but my wife has hidden it in the space/time continuum somewhere.

I'll be back!

I have now updated the first post to show the correct original wiring and fan.

**collo** · **02-24-07, 06:33 PM**

I've got an EP2500 on order, so I follow these quieting threads with interest.

It will be going into the room containing the manifolds, so I can probably live with it, but would still do the mod if I can get the bits.

Do any Aussie readers have a local source for these quieter 24v fans?

**Sonnie** · **02-24-07, 09:33 PM**

Thanks Chrisbee... of course my EP2500 is on order as well and Rodny wants to mod his fan too, so we will both be following this thread with interest.

I think we need to make it a sticky too...

**majorloser** · **02-25-07, 08:35 AM**

When you guys get your amps, let us know what the fan voltage is on the US model. Most computer fans are 12VDC. You can buy a ball bearing fan that runs slower and moves more CFM's at a much lower dB level. It looks like the one in the picture is a 80 or 90mm fan. Another nice thing would be to use one of the 12VDC computer fans that have a thermostatic fan speed control or use a pot to control the speed.

**Chrisbee** · **02-25-07, 03:57 PM**

Why would you think that the US market Behringer EP amps use a 12 Volt fan?

There are threads on the IB Cult discussing choice of 24Volt fan to make the amp quieter in use. Posters have been mostly American based.

The original fan is too noisy and doesn't run well with series resistance according to those who have tried.

A 12 Volt fan fed with 24 Volts would scream its little heart out until it died in agony.

**Rodny Alvarez** · **02-25-07, 04:48 PM**

I just order the fans!! they should be here Wednesday.
Sonnie! yours is coming too!!
Thanks guys!!

**majorloser** · **02-25-07, 07:05 PM**

Quote:

Chrisbee wrote:

Why would you think that the US market Behringer EP amps use a 12 Volt fan?

There are threads on the IB Cult discussing choice of 24Volt fan to make the amp quieter in use. Posters have been mostly American based.

The original fan is too noisy and doesn't run well with series resistance according to those who have tried.

A 12 Volt fan fed with 24 Volts would scream its little heart out until it died in agony.

???? Did I ask a bad question?
I asked what the voltage of the US model fan is. There's a lot of great fans ball bearing fans available in 12VDC. Some have remote thermostats that are meant to be attached to a computer heatsink. I guees maybe something along that line would be available in 24V. There are also small fans available in 120V there just not as quiet.

I personally did not buy a EP model Behringer and was curious since I still may if the fan noise can be eliminated. I bought the A500's and run them bridged. They remain very cool after hours of continuous usage. If I ever needed, I do have a 120V three fan system that was meant to mount on a large server rack. It is mounted behind the lowest rack blowing upward to cool the stack. I use a regular ceiling fan dimmer to slow them down yet still keep the closet cool.

**Rodny Alvarez** · **03-01-07, 09:56 PM**

Just finish my fan replacement!
I used a LED from a car alarm, you can see is the same plug, just make sure to match the wires position not the colors, on my plugs the red was the ground and the black was the positive!!!!

IMG_3474.JPG

IMG_3471.JPG

Hey Chrisbee!! look at the shroud (or tunnel

) on my, and look at yours, this is the way it was before I removed the fan!!!

IMG_3470.JPG

**FlashJim** · **03-01-07, 10:20 PM**

Rodny, what fan did you use?

**Sonnie** · **03-01-07, 10:29 PM**

I'll bring my amp with me Saturday, sounds like you can knock that out fairly quickly.

So, how quiet is that fan?

Be sure to let everyone know what fan you ordered too (like Jim...

).

**Rodny Alvarez** · **03-01-07, 11:04 PM**

I order my from Digi-Key, part P9739-ND fan 24VDC 1.30W 80mm, $8.25 + shipping.
http://www.digikey.com/
It is real quiet!! like 75% less noisy.
Sonnie!! your fan has the plug, all we have to do is replace the fan.
I read on the IB cult the let the fan blow out not in, this way you can clean the filter from the front! the factory blows in, what do you guys think??

This is what I called the shroud or tunnel!!

Slide1.JPG

**Sonnie** · **03-01-07, 11:25 PM**

Quote:

Sonnie!! your fan has the plug, all we have to do is replace the fan.

What... did one come with the plug and one not come with it?

**Rodny Alvarez** · **03-01-07, 11:46 PM**

Quote:

Sonnie wrote:

What... did one come with the plug and one not come with it?

NO!!

.... I had two plugs so I did yours!!

**brucek** · **03-02-07, 09:28 AM**

Quote:

I read on the IB cult the let the fan blow out not in, this way you can clean the filter from the front! the factory blows in, what do you guys think??

I would advise against it unless the front intake has a directive shroud identical to the rear one...

Also wonder if you saw this thread?

brucek

**Sonnie** · **03-02-07, 09:47 AM**

I think he had his ON and didn't realize it.

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