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D75A - noise


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#1 nielsenr

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Posted 13 November 2005 - 04:09 PM

Hi everyone.

I have recently puchased a Crown D75-A amplifier to power my Dynaudio Acoustics BM-6 monitors. I must say it sounds sweet!

However, I thought the D75-A was supposed to be completely quite, but I have found that my D75-A isn't. It has a low "buzzing" sound. Nothing to serious but enough to annoy me because I have the amplifier on my desk. The sound decreases when I put some pressure on top of the amplifier with my hand.

Is this normal for the D75-A or is there somthing wrong with mine?

Best regards, Rasmus Nielsen.

#2 DGlass

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Posted 14 November 2005 - 09:35 AM

This sounds like a mechanical vibration that is being induced by the AC transformer. There isn't much you can do about it except to apply a little pressure to the lid, as you have already found. Some are quieter than others in free space. Placing a D75 in a rack, with equipment touching it, usually elevates the mechanical noise as well.

#3 Ancient Audoiphile

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Posted 15 November 2005 - 07:11 PM

Hi David

Unfortunately, I have the same problem with my three D-75A amplifiers. A faint, 60 hertz mechanical buzzing sound coming from the AC transformers. I thought about popping the bottom cover and wedging a small piece of foam rubber between the transformer and the bottom cover.

Is this a good idea? Or am I just buying a whole lot of trouble with heating issues?

Oh, I am sure your wondering what am powering with a K2, K1 and three D-75A amplifiers. For now, my system is a 15" quad amplified 4-way. But, eventually I will get around to adding the sub-woofers.

Just go to the following site and read a complete description of what I am building.

http://www.audioheritage.org/html/perspect.../audiophile.htm

Thanks

#4 DGlass

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Posted 16 November 2005 - 02:37 PM

QUOTE(Ancient Audoiphile @ Nov 15 2005, 07:11 PM)
Hi David

Unfortunately, I have the same problem with my three D-75A amplifiers. A faint, 60 hertz mechanical buzzing sound coming from the AC transformers. I thought about popping the bottom cover and wedging a small piece of foam rubber between the transformer and the bottom cover.

Is this a good idea? Or am I just buying a whole lot of trouble with heating issues?

Oh, I am sure your wondering what am powering with a K2, K1 and three D-75A amplifiers. For now, my system is a 15" quad amplified 4-way. But, eventually I will get around to adding the sub-woofers.

Just go to the following site and read a complete description of what I am building.

http://www.audioheritage.org/html/perspect.../audiophile.htm

Thanks
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You shouldn't have a problem adding a piece of foam but make sure it won't melt or ignite if it gets hot. I can't guarantee that this will fix it completely either.