EP 2500 Fan Mod . . Revisited

[Hackomatic]

Okay . . been doin' a lot of digging around the various forums on doing the fan mod, but it "seems" there is no real consensus on the preferred way to do it or the preferred fan to use.

So . . Which 24v low db/ adequate cfm fan is preferred, AND . . blow in or blow out??

Saw where one fella used foil tape to seal the gap between the heat sink and fan shroud and then pulled the air from front to back instead of pushing it back to front as is standard. Thought that made good sense, but I'd like to hear the collective's opinion and go with the majority.

[brianpowers27]

Okay . . been doin' a lot of digging around the various forums on doing the fan mod, but it "seems" there is no real consensus on the preferred way to do it or the preferred fan to use.

So . . Which 24v low db/ adequate cfm fan is preferred, AND . . blow in or blow out??

Saw where one fella used foil tape to seal the gap between the heat sink and fan shroud and then pulled the air from front to back instead of pushing it back to front as is standard. Thought that made good sense, but I'd like to hear the collective's opinion and go with the majority.

I guess this question would depend upon the availability of air. If the back of the rack is closed you would probably want to push it... It also depends on what the other rack fans are doing. I would avoid having the amp inhale the exhaust air of other parts.

[blktre]

Its designed to blow in and through the front. Why would anybody change what the manufacturer has designed?

Id also like to learn more about getting a fan that already has the proper connection on it so i don't have to mess up the original fan to swap out the connection.

[chasw98]

I have done most every mod to the fan system you can do in an EP2500. IMHO the best way to go about this is to use a quiet off the shelf fan available form Digikey for about $8. You will have to solder the leads of the fan to the 2 pin plug that attaches to the fan controller board in the amp but it is better than using the 90 or 100 ohm 10 watt resistor trick to slow down the fan. My preference has been to suck the air in from the front rather than from the rear. 2 reasons for this are that the air from the front is usually cooler than the air in the rear of the unit, especially in a roadworthy amp rack, the second reason is that there is an air filter on the front of the amplifier that is worthless if the air is moving from the rear to the front. After several months or years of use, you will find that your heat sinks are covered in dust and dirt that can only be cleaned out by taking the amplifier apart and then getting to the heat sinks physically. If you suck the air in from the front, all you do is run a vacuum cleaner over the front filter and the amplifier will stay much cleaner.

Chuck

[AJ]

Lowering the speed of the original fan may get the noise low enough to solve your problem. Just remember these amps get extremely hot when asked to put out anything near their rated power. Shouldn't be any problem at room temperature.

Keep the fan blowing in as it was designed. Because the heatsinks are right up against the rear panel, next to the fan, it creates turbulence between the fins of the "wind tunnel". This will keep the 'sinks cooler even with reduced air flow. Also, reversing the direction of the fan will pull hot air around the motor of the fan, shortening it's life.

I haven't tried it myself, but this fan has been suggested on other forums.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=P9739-ND

[ctbowman]

I heard at some point in my life that fans are much more efficient at sucking than they are at blowing, every cpu or chipset fan I've ever had sucked from the hardware side out. I'd go with that. I don't think it will get hot enough for the fans motor life to be shortened either. And the next thing is that the bearing motor and balanced blades only get you so far. A pretty comprehensive test that I looked at a while back confirmed that the noise level of the fan directly correlated to the air flow and size of the fan. Basically... if you want a quiet fan, get a big one and run it slower... or you could use an ion propelled unit, but that's a whole new ballgame.

[Hackomatic]

Ordered my fan today from Mouser. The 24L with ball bearings.

http://www.orionfans.com/html/od8025.html


I haven't decided 100%, but I'm thinking of reversing the flow to pull from front to back. I'll probably make my final decision once I get inside and examine the layout.

Does anyone know another amp manufacturer that pushes rather than pull the cooling air through their units??

[chasw98]

Does anyone know another amp manufacturer that pushes rather than pull the cooling air through their units??


Crown, QSC, Crest, Yamaha, Lab Gruppen. Almost all major manufacturers have built units that go both ways, suck and blow. Something to keep in mind is that these amps were designed to sit in a rack with the front and rear covers taken off, left in the sun all day, and expected to put out full power for hours on end. When you transplant them to your controlled environment domicile and use a tenth of the available watts on average, a slower quieter fan will not impact the performance of these units unless you play headbanger at full volume over long periods of time. In which case, I would leave the original fan installed.

Chuck

[Hackomatic]

Made the modification with the Orion bb fan . . Quiet as a church mouse. After examining the entrails, I decided to pull the air through the unit, through the filter, front to back. I did use some foil tape to seal the area between the fan shroud and the heat sink, and also a small strip to seal the small gap on top of the two heat sinks, front to back. At 22 cfm, you can really feel the fan pulling the air straight down the "tunnel" when you place your fingers at the front of the heat sink. In fact, when everything was buttoned back up, you could feel the suction on the front filter. So, I'm pretty satisfied that this will end up flushing the cabinet more than sufficiently.

I was quite impressed with the build quality and the enclosure gauge when taking the unit apart. One thing that I did notice for those who might consider this mod is a little issue with the fan shroud, Get yourself some welting or at least some black tape to place along the bottom edge of the fan shroud. There are two notches in the shroud at the bottom for the wiring harness to pass through. The sharp edge of the shroud presses directly on the wires and I noticed it was making creases in the insulation . . not good!

[brianpowers27]

Do you suppose this fan would work for a QSC 1400 (series one)? I am not much for interpreting schematics but it appears that on page 4 the fan shows the need for 250vac?

Here is a link to the service manual. http://www.qscaudio.com/support/technical_support/schems1.htm

[Hackomatic]

Looks like it uses a 120vac fan. There is also a thermal controller that I imagine increases the speed when the unit reaches a certain temp . . I think it says 55 degrees c.

So to answer your question, no the 24vdc fan won't work, but I imagine there is a substitute that would if you found out the fan model currently inside the amp.

[brianpowers27]

Looks like it uses a 120vac fan. There is also a thermal controller that I imagine increases the speed when the unit reaches a certain temp . . I think it says 55 degrees c.

So to answer your question, no the 24vdc fan won't work, but I imagine there is a substitute that would if you found out the fan model currently inside the amp.

In theory, any 120vac fan should do the trick. I would be shooting for a low-medium cfm quiet fan that fits inside. I could splace the connector, if necessary.

[Hackomatic]

Yep . . most likely an 80 x 80 x 25mm 120vac fan, but I'd make sure before you ordered. I'd recommend a ball bearing over a sleeve bearing unit for longevity and the fact that it will probably take more heat.

[bogie]

FWIW, I was using an EP2500 to run four Quatro 15s (wired as two 2 ohm loads), and had zero problems with heat, even with some extended loud home theater music sessions...

[Hackomatic]

FWIW, I was using an EP2500 to run four Quatro 15s (wired as two 2 ohm loads), and had zero problems with heat, even with some extended loud home theater music sessions...


Is that with the OEM fan config, or with a mod?