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Crown Macro-Tech 2400 Noisy Fan


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#1 bobbysdad

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Posted 03 November 2010 - 03:09 AM

Hi all.

Can anyone suggest a way in which to make the fan on the MA-2400 a tad less noisy, please?

I've done my homework and found that the fan (fanformer) is an integral part to the circuitry by providing a source of + and - 15v power for various parts of the circuit.

I've also found one reference to there being available a different fan blade, which supposedly addresses this issue, although I'm not really sure how, if the motor itself is unchanged, and therefore must still be spinning at the same speed. Possibly a different pitch on the blades maybe?

Anyway, please please please, can someone come up with any ideas on how to quieten this beasty down for home use.

Cheers all,
Dad.

UPDATE:

I've just found this: optional replacement fan Crown part C 6594-3 is a quieter low velocity fan.

Can I order this from Crown USA, even though I'm in Australia?
I might be deaf, but I can still hear the bells......

#2 ouragan66

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Posted 03 November 2010 - 06:23 AM

QUOTE(bobbysdad @ Nov 3 2010, 10:09 AM) View Post
Hi all.

Can anyone suggest a way in which to make the fan on the MA-2400 a tad less noisy, please?

I've done my homework and found that the fan (fanformer) is an integral part to the circuitry by providing a source of + and - 15v power for various parts of the circuit.

I've also found one reference to there being available a different fan blade, which supposedly addresses this issue, although I'm not really sure how, if the motor itself is unchanged, and therefore must still be spinning at the same speed. Possibly a different pitch on the blades maybe?

Anyway, please please please, can someone come up with any ideas on how to quieten this beasty down for home use.

Cheers all,
Dad.

UPDATE:

I've just found this: optional replacement fan Crown part C 6594-3 is a quieter low velocity fan.

Can order this from Crown USA, even though I'm in Australia?



http://www.crownaudio.com/forums/index.php?showtopic=3709

ciao
Stefano

#3 bobbysdad

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Posted 03 November 2010 - 06:31 AM

QUOTE(ouragan66 @ Nov 3 2010, 10:23 PM) View Post
QUOTE(bobbysdad @ Nov 3 2010, 10:09 AM) View Post

UPDATE:

I've just found this: optional replacement fan Crown part C 6594-3 is a quieter low velocity fan.

Can order this from Crown USA, even though I'm in Australia?



http://www.crownaudio.com/forums/index.php?showtopic=3709

ciao
Stefano


Thanks Stefano, I did see that, which is why I updated my post, but I was hoping that wasn't the only alternative.

Cheers,
George.
I might be deaf, but I can still hear the bells......

#4 ouragan66

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Posted 03 November 2010 - 07:45 AM

Ciao George

perhaps the alternative is attenuating the tension that arrives to the fan...

Stefano


#5 bobbysdad

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Posted 03 November 2010 - 08:05 AM

Howdy Stefano,

Thanks again for your input.
It seems the 'normal' practices of just reducing the voltage to the actual fan by using a 10W resistor is not recommended, and in fact will stop the amp from powering up correctly.

I was hoping that someone from Crown, could offer their expertise, which would clear this up once and for all.

It would be ideal if it could be modified to use a thermostat and have the fan kick in when it has to, or at least make it two speed.
Maybe someone at Crown could just have a quick look to see if a factory sanctioned mod could be applied.

Home use usually isn't so demanding, (well, sometimes maybe), usually not much more than the 90W the amp uses at idle, so I can't see any overheating problems, until more power is used, therefore turning on the fan as necessary.
Anyone would have to agree, that one of these things for home, would be totally brilliant.
It's always overlooked for home use, because of it's fan noise at low volumes, and it deserves better because it really is a very high quality unit.

.... but again, I'll wait for a Crown Pro to hopefully add their bit to the thread. Otherwise, I'll just give it to my Rocket Scientist friend to see if he can come up with a solution.

Cheers heaps,
George.
I might be deaf, but I can still hear the bells......

#6 ouragan66

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Posted 03 November 2010 - 09:05 AM

Ciao George
kindly let me know what your friend , Rocket Scientist ,says...
wink.gif

Stefano


#7 bobbysdad

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Posted 03 November 2010 - 09:08 AM

QUOTE(ouragan66 @ Nov 4 2010, 01:05 AM) View Post
Ciao George
kindly let me know what your friend , Rocket Scientist ,says...
wink.gif

Stefano



biggrin.gif   I will.

Take care....


I might be deaf, but I can still hear the bells......

#8 kevvywevvywoo

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Posted 20 November 2010 - 02:52 PM

Since the fan windings also provide the power for the rest of the amp, it is not feasible to tamper with its supply.

You might simply have a worn bearing making it 'thrum' or 'beat'. Maybe soaking the phosphor-bronze olive bearing in thin oil will quieten it down a little. Dont use anything thick or else it wont acheive full speed when the amp's cold.



#9 bobbysdad

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Posted 20 November 2010 - 09:12 PM

QUOTE(kevvywevvywoo @ Nov 21 2010, 06:52 AM) View Post
Since the fan windings also provide the power for the rest of the amp, it is not feasible to tamper with its supply.

You might simply have a worn bearing making it 'thrum' or 'beat'. Maybe soaking the phosphor-bronze olive bearing in thin oil will quieten it down a little. Dont use anything thick or else it wont acheive full speed when the amp's cold.


Thanks kevvywevvywoo
It's not so much a noisy bearing. It's more like the sound of a vacuum cleaner!
Of course it wouldn't be a problem if I used it at gigs. It's getting a bit old, so I'd just like to retire it to light 'home duties'.
.... but as long as it's constantly sucking in so much air, I'm afraid it might suck one of my cats in.    blink.gif
Anyway, no hurry, so I've put it aside, and am using a Phase Linear D500 instead for now.
tongue.gif

I might be deaf, but I can still hear the bells......

#10 ouragan66

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Posted 22 November 2010 - 12:58 PM

Hi

http://www.crownaudio.com/forums/index.php?showtopic=3709

change the fan !!!
Now the fan noise is inaudible !!!

ciao
Stefano

#11 bobbysdad

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Posted 22 November 2010 - 11:42 PM

QUOTE(ouragan66 @ Nov 23 2010, 04:58 AM) View Post
Hi

http://www.crownaudio.com/forums/index.php?showtopic=3709

change the fan !!!
Now the fan noise is inaudible !!!

ciao
Stefano


Hi Stefano.   biggrin.gif

Yes, I will be.
I enquired at the local distributor, and they enquired at Crown. It took a week to get a reply.
The cost of the fan blade is $5.86 inc GST each and the freight anywhere within Australia is $16.50, but it gets sent from the USA to Australia via boat.... sad.gif so it'll take a while to get here, pro'ly mid Jan by the look of it.

George.  

I might be deaf, but I can still hear the bells......