fan noise

hi all,
only just found this site and looks very good!
i wonder can anyone help me cure my problem? to most this might sound daft but i like the audio qualities of amcron studio amps. i use a dc300a which is an indestructable battleship but i am also trying to incorporate an amcron geodyne 1 to bi-amp. problem is the fan noise on the later geodyne. ive had a peek and it is not the standard type computer fan but an industrial thing.
does anyone know how to silence it a little?
thanks in advance...

 

Fans sound noisy often becuase they are spinning too fast and have poor quality bearings, what I did on my PC was replace the fans with larger ones and ran them at a slower speed by fitting a resistor.

You have to be careful if you do this though, that the fan is good enough, otherwise you may end up with blown tranistors.

 

thanks for the reply,
the reason for the large noisy fan is that these amps spend thier working life in racks being driven hard. i need to find a way to keep it cool as it is class A but the noise it emits into my standard living room is a bit excessive. i dont think the fan is faulty, just built for a harder life than i can give it.

 

Any movement of air will make noise, but as AT says you can reduce the noise by using larger and slower fans. Something to remember is that turbulent air doesn?t cool as well as smooth flowing air so higher speed is not always better after a certain point.

You could always look at heat sinking the amp better so it doesn't need a fan.

Hell, what about water cooling it!

 

You could duct the fan output ....much like a cars exhaust... with baffles as long as you not obstructing the air flow this should be ok.

 

Turn the fan off then. If it is not driven hard it shouldn't need it, right?

 

if someone with experience of these amps told me i could unplug the fan for domestic use i would. they sound better hot anyway. i need to find the supply voltage and look for something a bit quieter. cant really fit anything bigger as its internally mounted into a hole in the chassis and the existing fan is about 5 inch diameter.

 

As long as the amp has thermal cut out protection, and most amps do, then you can safely unplug the fan and if it runs too hot it will simply shut down and you know you need the fan. I don't have experience with these amps though so I am not going to tell you it is defiantly safe... but it probably is, especially as they are designed to be driven hard..

 

your theory is so logical im going to drag an old pair of speakers out and try it.
the worst that can happen is that my amp or speakers ignite

 

can u replace with a silenx fan ? try http://www.leftclicks.co.uk/home.php

 

Silenx's marketing claims aren't strictly honest as they use some bizarre measurement method. 10dB quieter than similar sized/airflow papst? I don't think so...

Rick - there's a great many things that can be done, but it's hard to say without seeing the amp. You'd be welcome to bring it up for me to take a look (west yorks).

 

The Crown(or Amcron) DC300,DC300A and Mk II were Class AB designs,and hence did not run in full Class A,but in respect of their relatively small heatsink area,and that of their intended workplace(i.e. in studio or other professional areas),fan cooling was used.

They were,as you say,pretty much indestructible,but any fan cooled amplifier(and my Krells are no exception)can suffer from fan noise if the fans aren't cleaned regularly,or when their bearings begin to give up the ghost.

The following may be useful to you in terms of data sheets and service manuals,which Crown are sensible and open enough to place on their website.

http://www.crownaudio.com/gen_htm/legacy/legacamp.htm

There are links on this page to all of the various DC300 variants,along with service manuals,if you don't already have them.

Interestingly enough,they appear not to have been fitted with fan cooling as standard,but it is recommended in the DC300 manual for long,heavy use.
It may well be that at moderate levels,you may be able to manage without,and Crown may be able to answer that for you.

 

thanks for all your help,
i have visited the crown website and it is very good as you say. open enough to offer the service manual and circuit diagram in pdf to download. the only shortcoming of the site is a "contact us" tab.

it is not the 300a that is my concearn, the 300 has no cooling fan. mine is the very old mk1 and biased toward B.

the amp i am struggling with is a much later amcron geodyne 1 and is A weighted. my intention is to use the geodyne on the trebble because i find it slightly sweeter than the 300 and let the 300 handle the bass mid where it is much stronger and defined.

thanks for the offer to have a look isaac, can you send me a private message to disclose more accurately where you are?

 

isaac thanks again,
ive tried to send a pm back. dont know if it came because im not very clever with computers or this new forum. the upshot is that i might be trading the geodyne for another dc 300 which would solve my problems permanantly and in the ideal fasion.

thanks all for the help so far..