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And I should have mentioned that I only run one channel and I never go above -2.0/1.0dB in my AVR(up to +10dB)

If I get a second driver or a different single one that can take the ~2K watts then I will make sure I remember this.
 

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its good to know - i have a qsc amp and did the same thing - i changed out my fan and it seems to work great and no issues at all so far - i did clip once but i was playing the music loud - not the normal loudness - but really loud - plus i had the gains up a little past half - i have since left the gains half way -
 

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Without reading every page of this thread I run my ep2500's pretty hard. Has anyone ever had any problems with them getting too hot etc with this mod? With 3 of them running in my 1 room its pretty loud just don't want to have to worry about them getting to hot or over heating as I am pushing them hard when I am using them.
 

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Without reading every page of this thread I run my ep2500's pretty hard. Has anyone ever had any problems with them getting too hot etc with this mod? With 3 of them running in my 1 room its pretty loud just don't want to have to worry about them getting to hot or over heating as I am pushing them hard when I am using them.
I ran into problems. But I am a minority. I personally suggest to leave it stock, but many have gotten away with it no problems.
 

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I have fitted a 120 ohm 1w resistor inline on the positive line of the original fan, first I fitted a potentiometer and upped resistance until the sound of the fan was reduced enough and made sure there was plenty of air movement still then checked the resistance of the pot and replaced with the resistor. So far it seems to work well I can't hear the fan at -35db from 1.5m away and there actually seems to be more airflow at the front of the filter?? possibly just less turbulant flow and more laminar

I am also planning to fit a mono 3.5mm jack and a relay so it can be switched from a normal receiver switch automatically.

Ash
 

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I notice this amp kicks out a bit of heat even when idling. Well, it stands to reason the 300 watts or so it is taking to idle, is being converted into heat.

The Digikey fan was probably selected partially due to its low noise. Notice, when you look up the specs, it is the quietest but also the lowest flow of a series of several fans. If you replace the letter "L" with an "M" it takes you to a fan which would be louder, but quite a bit more output/flow...and the "H" is even a notch louder/higher flow.
 

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I have fitted a 120 ohm 1w resistor inline on the positive line of the original fan, first I fitted a potentiometer and upped resistance until the sound of the fan was reduced enough and made sure there was plenty of air movement still then checked the resistance of the pot and replaced with the resistor. So far it seems to work well I can't hear the fan at -35db from 1.5m away and there actually seems to be more airflow at the front of the filter?? possibly just less turbulant flow and more laminar
I think I like this approach better than a fan swap. This seems like it would get the best air flow while customizing the maximum amount of noise that can be tolerated. If someone could tolerate more noise, they could simply use a different value of resistor. I am not an electronics expert but I don't see how this simple electrical change could damage the unit. If anyone has any other input, please speak up. Of course, it could still get too hot I guess but I think that is very unlikely unless you are pushing something *EXTREMELY* hard.

Mike
 

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just switched out my fan with one from Digi. The sound is much more tolerable. I simply cut the wires and used wire nuts to connect them together. Took all of about 10 mins, most of it screwing and unscrewing. It is now quieter than my projector (epson 7500) and about as loud as my toshiba HDDVD. I'll let you know if it overheats or has problems.
 

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I am not an electronics expert but I don't see how this simple electrical change could damage the unit. If anyone has any other input, please speak up.
Yes, you certainly can use a series resistor to lower the voltage across your fan to slow it down, but it's considered a bad idea with a DC fan. They really prefer their designed terminal voltage to be present, so depending on the load, they will be able to draw the appropriate current, specifically on start up where the load is the greatest.

The drawback of introducing a fixed series resistance, is when the load on the motor increases through startup requirements (or eventual bearing or sleeve wear). This increased load increases the motors current and subsequently the voltage dropped across the fixed resistor, thus supplying even less voltage for the motor and so on until the motor stalls or can't start in the first place.

The only correct way to control speed on a DC motor is to supply the required specified voltage with a varying pulse width through a speed controller.

There are kits available at very cheap prices to affect a speed change in a DC fan. You could hide and connect it externally with connectors, so as not to modify the amp for warranty or sale concerns.

The best solution though is to simply buy a quieter fan.

brucek
 

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For the aussies, RS components stock the papst fan stock # 299-1403. Awaiting my EP2500 will let you know after i mod mine with this fan.(papst part #8414NGL 1500rpm 12db 24vdc).
So got it in yet? How's the performance of this fan? Not cheap. Worth the dolleros$$?

Cheers
S
 

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Yes, fitted some time ago. Results great as far as noise reduction is concerned, can't really say about heat wise as i haven't yet completed my 18 sonos yet. :daydream:Only have the EP2500 powering a single Audax 12 in a EBS enclosure, not exactly what you would call a challenge for this amp.
 

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Okay, I just purchased the papst for a whooping $55 AUD. However, I have noticed the specs rate the CFM for the papst at 19.4 and the db at 12. However, the Panaflo FBA08A24H1A appears to be rated at 39.6 CFM and so naturally, at a higher db of 32. So the panaflo has 50% more airflow at a cost of almost three times the noise.

So I'm happy I have the quietest fan (if you believe the specs) however, I am little concerned about the airflow. Any thoughts as to whether it will be sufficient (it gets pretty hot here in the middle of summer - and no air con.)? Amp's used for HT primarily.

Thanks for the heads up gtvben

Cheers,
S
 

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Sam, I am assuming (read hoping) that the air flow for HT applications will be sufficient with the papst fan - its not like we are running the amp into 2 ohms flat out all night and mounted into a packed rack as the unit was designed for....
 

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Yep, me hoping too. I'll definitely be keeping my eye on things next summer though.

I installed the fan yesterday. It's quiet but still audible from 7-8 feet away (i.e. the listening position). Still, it's a million times better than the hair-drier noises of the stock motor and so now, quite acceptable (to me). I should note that my amp is sitting exposed (to enhance cooling). If it was in a more restricted cabinet it would probably reduce the noise further. I also installed the fan blowing out - I would think blowing in would again reduce noise further.

Re cooling - there does seem to be some good airflow coming out. For people's information I found the stock fan's specs here: http://www.bisonic.com.tw/27dc8025.html

Unsurprisingly, the stock fan is rated at 55.53 CFM and 40.9db noise! Speed is rated at 4000rpm vs. the papst at 1500rpm.

Thanks everyone for the helpful tips here.

Good luck with the build Ben - will we get pics?

PS. does anyone know if the papst fan will increase in speed as the temperature increases (as did the stock fan)?
 

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Hi Sam,
I would suggest you mount the fan blowing in as originally designed, also the temperature dependant speed control is in the circuitry of the EP2500 so yes the new fan fitted will vary in speed with temperature.
Many projects on the go at the moment, but will send some photos of my sonos when I finally get to them.
 

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I thought I would post an update on the BEHRINGER EP4000 fan mod. I replaced the fan with the NMB-Mat FBA08A24L1A mentioned in this thread. I am very pleased with the results. When I first bench tested the amp after the mod I thought I did something wrong, it was dead silent. I had to look to be sure the fan was spinning. I ran a full hour long session of some massive bass tracks into my dual AudioPulse LMS subs. The amp was still running cool, so it appears the fan does a good job of cooling the EP4000.

Thanks all for the info! At last slience between tracks and no noisy fan for soft intro's

BTW I got the fan at Newark's website for $8.68.
 

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I must also testify to the quietness of the fan mod. I had changed out three of mine and forgot (strangely enough) that I had not changed out the fourth one. The very second I cut them on I was wondering what in the world was all that noise. My first thought was that one of the fans had a bad bearing or the fan blade was brushing against something. Fortunately it was just the original fan. Of course I changed out the fan and all is superbly quiet... very quiet!

There is simply no way you can use these amps with the original fans unless you got the volume cranked high on everything you listen to... and then during quiet scenes, it will be very noticeable.
 
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