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Fans on amps.

Ive been checking out some posts about fans by amps but cannot find anything about them being good or bad for the amps. This is what I would like to know. Ok. I have a Krell Fpb 600 and I listen to my music about a 28-30 volume on my ARC Ref 6 which is pretty loud most of the time depending on recordings. Tonight I felt my amp like a lot of times and felt very hot like u could fry an egg on top. This is the normal with a few hrs of listening. Anyway I put a fan on the right side of amp and about a half hour later I checked the right side and was significantly cooler I mean like a night and day difference between the right and left top and heat sinks. I was wondering if adding 2 fans one on each side to cool the amp down would do more harm than good. Would I get more life out of the amp with fans ? Or are amps designed like that without using fans and just heat sinks to get rid of the heat. Btw my amp has plenty of ventilation as it is on the floor. Thanks. 
128x128Ag insider logo xs@2xtattooedtrackman
teo_audio
2,197 posts
 
I do it my way, you do it yours.

My particular 12VDC fan with the 4.1vdc power supply has been running for over 12 years. 24/7.

Yes, is a fine example, not an outlier. But the power supply and fan were decided upon --together. Tested. Those numbers will not fit all situations.

I’m using it in a situation where no fan is actually needed, not in a situation where a fan is required to not fail. That would be like ..uhm..a closed cabinet with no visual access to the fans to check on them--combined with an amplifier that is likely to die if left in a hotbox like a sealed cabinet. In that scenario the fan is ultra critical. Not a good idea to make the life of the amp dependent on a $5-$20 fan and given power supply for said fan...

As for the rest, we can do it ourselves and arrive anywhere we want or with as much engineering rigor we may desire.

Most folks (95% plus, as a guess) want pre-fab solutions, so that is the reasoning behind indicating commercially available devices and critiquing commercially available devices.


ieales's avatar
ieales
1,201 posts
 
85°C caps rated for 2000h in an amp running @ 35°C [95°F] have an rated life of 8000h.
Oops. 2^5 = 32. 2000h rated are 64,000h @ 35°C. 32k days @ 2h/d ≈ 88y.

However other factors limit the life other than temperature, so 15y is a safe limit.
stringreen's avatar
stringreen
6,478 posts
 
I used to own an Ampzilla which had a fan...never quiet enough
ieales's avatar
ieales
1,201 posts
 
Ya shoulda PM'd me back in the 70's. Mine was dead quiet ;-)
wspohn's avatar
wspohn
609 posts
 
Fans on power amps are rarely quiet enough for listening to acoustic music. 

One friend had a fan cooled power amp and when we tried to listen to solo violin it was like attending a concert with a DC-6 winding up for take off in the room. Had we been listening to loud rock it probably wouldn't have mattered.

You can get away without fans if you have proper heat sinks, but that is expensive. Take a look at the pics of these Classe Class A amps:

https://www.aussieaudiomart.com/details/649274239-pair-of-classe-dr3-vhc/images/1228060/

The amps put out into the hundreds of watts of heat just sitting there (a bit less if they are converting some of the current into sound.

Another friend had some fan cooled Crown (commercial) amps - I couldn't listen to them with the fans going beside us.
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