Behringer EP2500 Fan Modification

[mike c]

step 1: buy your pro amp

step 2: buy a 24v fan
digikey part number: P9739-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=P9739-ND

since i don't think digikey accepts international credit cards, WmAx was kind enough to ship the fans to me through USPS [thank you very much for that Chris]

step 3: open up your amp
[make sure the amp is unplugged]
unscrew the 4 screws on top holding the cover to the heatsinks
unscrew the TOP left, back and right screws (no front screws) - do not unscrew other screws NOT bordering the top of the amp
[IIRC, there 4-5 screws each of the sides and 5-6 screws at the rear]

step 4: replacing this fan with this fan

when the cover is off, remove the grill protecting your fingers from the fan, it holds the grill, the fan and the "shroud"

step 5: splicing the wires
you are gonna cut this wire ...

the one that says vw-1

[those are not my dirty hands] I did everything BUT splice the wires.

spliced with electrical tape

step 6: put everything back together
[but while we have the unit open]
see the caps and heatsink

BTW, the original design has the fan blowing back to front. "creating an unserviceable vacuum cleaner."
so I changed the direction of this fan to blowing front to back. the fans will have arrows pointing where the fans turn and where they push air to.

 

[mike c]

after going through all that work, what do you get?

at the front "before" 69db

at the front "after" 61db

at the back "before" 80db

at the back "after" 75db

please note that I did this at work and the noise floor is around 60-61db

 

[Rickster71]

Hi Mike, looks like an interesting project.
Can't wait to see more pics.
The fans you're using list the bearing type as "Hydro-Wave"
What's that?

 

[mike c]

Hi Mike, looks like an interesting project.
Can't wait to see more pics.
The fans you're using list the bearing type as "Hydro-Wave"
What's that?

haha, i have no idea.

this fan has been recommended by WmAx / Chris and he said it is at least 16db quieter than the stock fan which btw is a bit disturbing, even with my ACU on.

 

[Rickster71]

Mike,
I did find some good info on fan bearings.
http://www.silentpcreview.com/article690-page2.html
I have fans on all of my amps; so I'm really interested in your project.
Rick

 

[mike c]

i don't know when i can finish this, but if you can't wait ... there's another fan mod thread on this exact same amp

http://www.hometheatershack.com/forums/diy-subwoofers/3658-quieter-fan-mod-behringer-ep2500.html

edit: i must note though that thread confuses the crap out of me. (the initial pictures have the new fans instead of the original ones)
but the pictures and discussion are of great help.

 

[mike c]

funky digikey packaging

for some reason it is "cheaper" per fan to buy 4 fans than 1 or 2 or 3 (all I need now is 3 more pro amps using 24v fans)

 

[mike c]

fan mod completed, now to test it in actual use

 

[jvgillow]

For those who want to do the resistor mod method instead, this are the instructions I followed back when I had my EP2500 (sold it a little while ago).

http://www.cwitt.com/epfanmodification/index.html

 

[WmAx]

You did not get as much attenuation as has been achieved in best case scenario(roughly -15dB), but maybe your work's noise floor is causing a little bit higher reading as you alluded to.

You can also combine the low noise fan with a resistor network to slow the fan RPM if it's still too loud; you should be able to buy resistors available locally, I hope - LOL. For domestic use, not much air flow is needed: remember in pro use, it is common to use averaged power levels near the limit of the amp. In domestic use, the only time high power is used is when short dynamic bursts are reproduced.

-Chris

 

[annunaki]

after going through all that work, what do you get?

at the front "before" 69db

at the front "after" 61db

at the back "before" 80db

at the back "after" 75db

please note that I did this at work and the noise floor is around 60-61db

Your measurements could be skewed some by having the mic on the spl meter in the airflow of the fan.

You should take new measurements while being careful to keep the mic out of the airflow.

 

[mike c]

Your measurements could be skewed some by having the mic on the spl meter in the airflow of the fan.

You should take new measurements while being careful to keep the mic out of the airflow.

i'll try to take new measurements in the HT, with and without the ACU noise floor. (but i'm not putting back the old fans )

You did not get as much attenuation as has been achieved in best case scenario(roughly -15dB), but maybe your work's noise floor is causing a little bit higher reading as you alluded to.

You can also combine the low noise fan with a resistor network to slow the fan RPM if it's still too loud; you should be able to buy resistors available locally, I hope - LOL. For domestic use, not much air flow is needed: remember in pro use, it is common to use averaged power levels near the limit of the amp. In domestic use, the only time high power is used is when short dynamic bursts are reproduced.

-Chris

what's important I think is that it is now much quieter than my projector fan. and with the ACU on, totally disappears. it is inaudible from the listening position now with or without the ACU on (but I never NOT turn on the ACU)

 

[mike c]

i re-measured with an SPL meter the rear fan ... since 60db is the lowest the SPL meter can detect, i started from 1" from the rear fan and moved the SPL meter away.

basically, the sound only registers 60-61db from the rear IF the spl meter is 5-6" away, further than that, the SPL meter doesn't even detect the fan noise.

 

[Matt34]

Bump for a good write-up Mike. Getting ready to do this to my amp soon.

 

[annunaki]

The Fan replacement is well worth it. Mine is loads quieter now.

 

[armstrr]

The Fan replacement is well worth it. Mine is loads quieter now.

i'll 2nd that. it took less than 15 min, and that is for someone with junior soldering skills.

i thought i might be able to avoid doing this mod because i set the ep2500 at the front corner of the room the right speaker enclosure. that is about 12' from the primary seating area. with the original fan, it could be heard clearly from the main seat. with the new fan it can't be heard from more than 2', and even at 2', that is only because i am trying to hear it.

 

[Wafflesomd]

My first question is, is the new fan have a higher CFM rating? Maybe it allows it to operate at lower temperature at equal output, compared to the original fan.

 

[mike c]

My guess is the cfm is lower. But we home theatre users dont need the higher cfm since we don't tax this amp as much as pro users

 

[ParadigmDawg]

Yep, my EP2500 stays pretty darn cool to the touch and I can't hear the fan at all. Now come up with a fan mod for the PS3.

 

[Wafflesomd]

I'd like to try fan mods myself. A higher CFM, probably louder fan.

I'd be going for lower operating temperatures at bridged 4ohm, high output.