EP2500 10 minutes no load-hot 180deg f (summary: do NOT reverse your fan direction) - AVS Forum
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post #1 of 27 Old 12-03-2011, 08:49 AM - Thread Starter
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Sept-24-2011 I posted in this thread, My EP4000 is getting hot very quick , but my issue seems different so making a new thread.


When it's hot, it's HOT, my amp I mean.

My EP2500 still works, but runs too hot as posted in the above AVS link.
I've been using it for only 2 hours max at a time, then off with the HT.

I finally had time to take the EP2500 out of the rack this morning, take the cover off, and inspect it.
Everything looked "ok", nothing looked "burned" brown/bubbled, etc.

Plugged it in the wall, turned on, nothing hooked to it at all.

10-12 minutes later, look at these temps, taken with handy IR thermometer, and felt with my fingers.
What are those white ceramic (I think) things that are getting so hot so fast, w/o any signal?? either they are at/near room temp 70's, or cooking HOT.
Any idea/suggestions to trouble shoot this??


All the other components feel just "normal".

I will cross-post this at my other forum, IB Cult, as a lot of guys there also use this amp.

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post #2 of 27 Old 12-03-2011, 09:07 AM
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wish I had a sensor like that, I have 2 EP4000s and one gets hot the other doesnt...I'd like to check component by component and see whats getting hot on one and not the other
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post #3 of 27 Old 12-03-2011, 09:28 AM
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Quote:
Originally Posted by mtbdudex View Post

What are those white ceramic (I think) things that are getting so hot so fast, w/o any signal??


Those are resistors

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post #4 of 27 Old 12-03-2011, 10:08 AM
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Mike,
Always a pleasure viewing your pics, that pic of the EP2500 internals is the way I wish everyone would submit pics! Well illuminated, in focus, etc..., anyway good lookin' out wrt pic quality.

Now, could you refresh my memory about your driver load? Two channel, mono? Impedance? Also, this amp is fan modded, right?

I'm not familiar with heat buildup causes in these amps, but,...as with any solid state amp, heat is death! These things are so modestly priced, we through-put mucho LF, ULF, with really raises current levels. These high current levels is what really pumps up the heat produced,...and hopefully, all the different elements of the amp can dissipate their fare share.

You mentioned infrequent use, do you allow adequate cool down time after a viewing/prior to turning off? Everyone approaches things differently, however I prefer to limit thermal cycles in my amps/gear, so although it's not energy prudent, I prefer to leave everything I use, on all the time. Professionally, one never powers down unless absolutely necessary, and I carried this over into my best practices at home.

I hope your amp isn't nearing it's useful end, but I'm guessing it is. It seems like I've read about a handful of these becoming problematic recently. Fwiw, stepping back and viewing this in added context, it is a $300, 2000 watt amplifier

Perhaps someone more knowledgeable in this can offer up some insight.



Good luck

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post #5 of 27 Old 12-03-2011, 10:14 AM
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I've had times with my PA rig that if the ground wasn't properly bonded, my PLX's (with switching PS's) would heat up like a oven. And operate with a fraction of output.
However my RMX's (w/ conventional PS's) were fine.

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post #6 of 27 Old 12-03-2011, 10:55 AM - Thread Starter
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Thx FOH, a DSLR and adding text helps bring clarity to discussion.

For my IB sub, the (4) AE 15" drivers are like this:

Re: 5.5ohm
1/5.5 + 1/5.5 = 1/R(e) = 0.3636
R(e) = 2.75 ohm load on each channel, so should not overload the amp.
(This was "ok'd" in my IB Cult thread)


I don't leave the amp cool down per say, when we are done watching a movie usually there is a 3-5 minute clean up and the whole set-up is just on but not really working while we go thru that routine.

The Amp is triggered on/off via 12v trigger from the AVR....
Yes - fan mod for lower noise.

It still works, I'm just kinda scared about the heat.

Definitely making this much heat just sitting "On" is a sure early warning sign.

Curious why this is happening, at least for 2.5 years it ran relatively cool w/o any issue.
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post #7 of 27 Old 12-03-2011, 01:12 PM - Thread Starter
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FYI:
The fan mod was the 1/2 speed fan for lower db, and direction reversed from stock.
>>I just flipped the fan so now flow direction is stock.
>>Fan goes on instantly when turned on

a) Waited 4 minutes, and everything was getting quite hot.
b) After 30 minutes of "idling", the components are all at their same "HOT" temps, but the alum heat sink is dramatically cooler (top) than before and the exit air coming out the front is not hot at all.
>>In hindsight, looks like from this issue I can clearly see Behringer engineered that heat sink/components/air flow as a system to efficiently dissipate heat instead of letting it build up, and airflow of the sink definitely is part of the engineering.

Picts of white ceramic components

70 deg f components


180 deg f components


180 deg f components


140 deg f components



[update 5pm]
2 full hours later its stabilized, exhaust is cool, those specific components are HOT, but the alum heat sink is just warm, 90's, and only in certain areas.
I'm putting the EP2500 back into the HT.
Would recommend only the low db fan, and keep stock airflow direction.

[update 6pm]
I plugged the EP2500 into my Panamax 5300, it went from 124v 0.7 amps (idle draw of : PS3 + Denon AVR-4308CI + Furman PS-PRO II PWR COND/SEQ) to 1.1 amps, meaning the EP2500 idle current is 0.4amps w/o any signal.
It stayed at 1.1 amps for 45+ minutes, so steady state.
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post #8 of 27 Old 12-03-2011, 01:45 PM
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When I did the fan mod, the amp would shut down with decent use. Put it back to stock and moved it to another room, and all is well. Runs all day long many times.
I dont think the fan mod is a good idea, and certainly reversing flow is even worse.

Lot's of low rent stuff stacked up into a medium rent pile.
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post #9 of 27 Old 12-03-2011, 03:18 PM
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What the general consensus regarding airflow direction with the EP series? IMO, typically one pulls air through a chassis for cooling, and I agree. Pushing air, through the sinking area, then into the filter media, seems back-wards.

Wouldn't drawing air into the front, thereby essentially utilizing the filter in somewhat of a better manner seem optimum? I realize there are other point air enters the chassis, but this seems logical.

Mike, what made you reverse airflow the first time, and why did you return it back the stock direction?

Additional thoughts?

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post #10 of 27 Old 12-03-2011, 03:21 PM
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Quote:
Originally Posted by digital desire View Post

When I did the fan mod, the amp would shut down with decent use. Put it back to stock and moved it to another room, and all is well. Runs all day long many times.
I dont think the fan mod is a good idea, and certainly reversing flow is even worse.

I don't think the fan mod is a good idea either, but everyone's different. Also, I think stressing it with full output, HT style LF/ULF(5-20hz), at loads lower than 4 ohms is a recipe for subsequent failure.

YMMV

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post #11 of 27 Old 12-03-2011, 07:45 PM
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The fact that those resistors are in ceramic cases would tell me they are designed to survive at high temp. So...if the amp is working fine, I wouldn't worry about it.
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post #12 of 27 Old 12-04-2011, 06:01 AM
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Mine has had very light use and runs warm with 0.5 A idle. Digikey fan. The comment by kryp regarding 2 identical amps running different is interesting. Kryp can u measure idle current?
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post #13 of 27 Old 12-04-2011, 06:17 AM
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Quote:
Originally Posted by mtbdudex View Post

the EP2500 idle current is 0.4amps w/o any signal.

When you say 0.4 amps it seems innocuous enough. But put your hand on a 40w incandescent light bulb and you'll get a better idea of why you shouldn't be reducing fan capacity or reversing airflow.

Quote:


The fact that those resistors are in ceramic cases would tell me they are designed to survive at high temp. So...if the amp is working fine, I wouldn't worry about it.

They're rated at only 3 and 5 watts, so it's not going to take that high a temperature to cook them.

Bill Fitzmaurice Loudspeaker Design

The Laws of Physics aren't swayed by opinion.
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post #14 of 27 Old 12-04-2011, 10:17 AM
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Engineering is always a series of compromises. Your goals are a physically quiet amp. The engineers who designed the thing had other goals.

As my Father always said when I was a kid and started modding stuff: "What do YOU know that the engineers who designed, built, and tested it do not?"

Most of the time my two ep's see pretty light duty. Sometimes they do not. ON the modded one at funtime, it thermally overloaded and quit. I consider myself lucky it did not let out the magic smoke. Once reverted back to stock, you can beat the tar out of it and it keeps on trucking.

As far as the reversed fan flow, I would think that one reason may be it is because you can increase mass flow on the cold intake air easier than the less dense exhaust. As far as the filter in front, well, only one theory. Since these are sitting in racks and sometimes aimed right at the sound board personnel, it may keep any debris that it sucked in on the intake side from getting ejected forcefully into their face?

Lot's of low rent stuff stacked up into a medium rent pile.
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post #15 of 27 Old 12-04-2011, 12:52 PM
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Quote:
Originally Posted by digital desire View Post

As far as the filter in front, well, only one theory. Since these are sitting in racks and sometimes aimed right at the sound board personnel, it may keep any debris that it sucked in on the intake side from getting ejected forcefully into their face?



Thanks for that, .... as if the lights going down, and the act taking the stage weren't enough stress,....one more item for my OCD self to be consumed by. Amp rack projectiles,.... straffing me upside my head, like an A-10 on the highway of death. Great,..thanks.

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post #16 of 27 Old 12-04-2011, 01:33 PM
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IMO

Stepping back and examining the big picture;

We're tasking these $300 amps,... with out-putting high current levels of infra-sonic signal voltage, coupled to near dead short loads, and then we mod their thermal capabilities.

These EP's are great, I have some,...but man we need to keep our expectations realistic. When designed, the engineering team easily saw the amp hitting the clip indicator with every kick drum beat, and doing so all night long. But wide-band blasts of BluRays like HTTYD, spanning from 3hz-60hz recorded full scale,...is really brutal on these things.

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post #17 of 27 Old 12-04-2011, 01:48 PM
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IIRC, isn't there a gap between the fan and the heatsink in stock form? Taping it sealed may be removing part of the cooling equation that is designed into the product for the rest of the assembly also ( like those emitter follower resistors.)

Lot's of low rent stuff stacked up into a medium rent pile.
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post #18 of 27 Old 12-04-2011, 03:33 PM
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Quote:
Originally Posted by digital desire View Post

IIRC, isn't there a gap between the fan and the heatsink in stock form? Taping it sealed may be removing part of the cooling equation that is designed into the product for the rest of the assembly also ( like those emitter follower resistors.)

Yes there is, it's like 1/4" or so

Upon seeing it for the first time, I too thought it was intentional,...as I think that's a pretty sloppy design aspect if merely coincidental, and from poor tolerances. By taping it, you'd think it'd make the output devices cooler, yet the remainder of the components less so. Conversely, most cooling tunnels like this are properly shrouded.

Any updates Mike?

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post #19 of 27 Old 12-04-2011, 06:55 PM - Thread Starter
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FOH/digital desire;
(went to U of M vs Iowa bball game this afternoon, just noticed this update.)

Thx for bandwidth, yes when I did the amp fan related mods (lowed db fan and reverse direction) I also added that silver HVAC tape for what I thought was improving airflow thru the heatsink and thereby improving convection and removing more btu's, which....should keep it running cooler?

Anyway, like stated yesterday I reversed the fan direction and did remove the silver HVAC tape.
Back to "near stock", I did NOT re-install the original "loud" fan.

When I built my IB sub 3 years ago initially zero amp mod for a few months, and at low passages I could hear the fan, so did the fan mod.

I noticed the heat a few months back, sorta watched it but did nothing.
Being totally honest, possibly it always was running that hot -or near that hot but I never paid attention?? Definitely I never measure it, funny feeling wires/wood 170def f sure feels "hot", but won't burn your skin, but measuring it totally woke me up.

As a re-cap, when I opened the rear doors to the A/V rack it was hot and upon measuring really hot as shown in this old picture with mark-up.


Update as of tonight (Sun 12/4 9:30pm)
Upon coming home from the U of M vs Iowa bball game (UM won), and eating Reuben sandwich bought from zingermans deli, My boys and I watched via Blu-ray StarWars:III Revenge of the Sith.
Not at full reference level, about -12db, still gave the amp a decent workout.
Good news: working fine and running just warm, not hot!!

I think the mystery is sorta solved - and definitely advise people do NOT mess with airflow direction unless you know the "whys".
For my knowledge: why does the amp at "idle" take 0.4 amps? Just to keep the capacitors fully charged??
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post #20 of 27 Old 12-04-2011, 09:17 PM
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Amps are biased slightly (current running through the outputs) to reduce/eliminate crossover distortion. That is not crossover like a speaker, but crossover from switching polarity in a sine (signal) wave. True class A amps (not these!) are fully biased, and thus have huge mass, and not a (relatively) large amount of total output power.

Lot's of low rent stuff stacked up into a medium rent pile.
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post #21 of 27 Old 12-04-2011, 10:03 PM
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Awhile back I reversed the fan on my ep2500 as well. It seems logical that drawing the air through the filter and out the back would work best but instead it runs hot as hell. I even added tape from the fan to the shroud to ensure the best draw. So I put mine back to the original direction and slowed it with a zener diode. Runs quiet enough and never more than vaguely warm even when blasting the IB at 120db+.
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post #22 of 27 Old 12-05-2011, 05:28 AM
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Thanks for the updates Mike,...good luck.

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post #23 of 27 Old 12-05-2011, 05:25 PM
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Quote:
Originally Posted by Jesse S View Post

Awhile back I reversed the fan on my ep2500 as well. It seems logical that drawing the air through the filter and out the back would work best but instead it runs hot as hell. I even added tape from the fan to the shroud to ensure the best draw. So I put mine back to the original direction and slowed it with a zener diode. Runs quiet enough and never more than vaguely warm even when blasting the IB at 120db+.

the fact that the fan is trying to push air which is less dense (already heated) might explain part of it.

This discussion on idle power consumption and heat, hits on why I am not as much of a fan of these amps compared many on here and other forums. But lets face it...considering the price and power output, there has to be a compromise somewhere, right?

In the winter, the heat isn't such a bad thing. In the summer, you are paying for the electricity to make that heat, and then paying again for your A/C system to remove the same heat.
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post #24 of 27 Old 12-06-2011, 03:12 AM
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No where else are you going to come up with about 2 kilowatts for under 400 bucks. The amp is great in stock form, spend the effort to move it out of the theater.

Lot's of low rent stuff stacked up into a medium rent pile.
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post #25 of 27 Old 12-06-2011, 03:59 AM
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Quote:
Originally Posted by digital desire View Post

As my Father always said when I was a kid and started modding stuff: "What do YOU know that the engineers who designed, built, and tested it do not?"

Engineers are human and they get things wrong all the time. Just because they designed it a certain way does not mean they designed it the correct way. As you said before, the bean counters also have a hand in the design specs.

Dumb enough to spend lots of cash on this junk!
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post #26 of 27 Old 12-06-2011, 11:25 AM
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Those look like ballast resistors for the outputs.

Are you sure the thing isn't oscillating, perhaps ultrasonically? That would heat it up quick...

"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley
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post #27 of 27 Old 12-06-2011, 08:11 PM
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Interesting...

I have a new EPX 4000 myself and fortunately I have my rack behind a door so the fan noise was not objectionable. I was going to look at using a NTC thermistor inline with the fan(s) such that when the temperatures inside the amp was low (e.g. not working too hard and thus SPL output is low) the fan would run slower (less noisy). As the temperature increased, the fan would run faster. i.e. the NTC thermistor has lower resistance at higher temperatures.

Never thought too much more about it just an idea......


BTW, just a word of caution opening up those amps.... I noticed in the picture they contain several 12,000 uF capacitors that can stay charged up long after you pull the plug and give you a nasty shock (or worse). Be careful poking around with stuff inside there....
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