Denon HA-500 noise issue

[guyb]

Hey all,

I am having a little issue with my Denon HA-500 head amp and wanted some help!

Currently, my Denon HA-500 head amp is performing great and sounding amazing. There is however one issues with it and, although I have a few guesses, I am not sure want to do about it.

The issue is that they unit itself make a humming noise. If I take the outer of the case off - the noise total disappears. If I put it back on there it is again. If I put my hand on top of the unit and press down, the noise nearly goes. If I put something heavy on top it, the noise nearly goes.

I have tightened the power supply to make sure it is not vibrating. I tightened (and loosened) the case to make sure it wasn't vibrating. No difference.

Is the top of the case vibrating and acting like a microphone? And if so, what can I do?

Thanks

Guy

[anubisgrau]

the case - you mean the chassis? obviously not grounded and it has to be done. it always freaks me out when i see this thing omitted in a phono chain. i recently had an exactly similar thing with a top brand $$$$$$ MC SUT, i just couldn't believe when I opened it to find a floating chassis acting like humming antenna.

what can you do? well you need a piece of wire to connect the chassis with a main grounding of the unit - and for sure, no matter if the power cable provides grounding or not, i would try to ground it via a back panel GND connector, this could sort it out too. if you are not sure what you are doing, there's a plenty of ppl here who can help, it's a routine thing.

[guyb]

Hey,

Thanks for the reply.

I have a ground wire connected between the ground output on the HA-500 to my amp.

The chassis is in 2 bits - the bottom bit (that has the ground post) and the top bit. Without the 'top' bit there is no noise.

So, from what you are saying, I need to connect a ground wire between the bottom part of the chassis and the top bit of the chassis - correct?

Thanks

Guy


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[Arkless Electronics]

It's got FA to do with grounding! As you first surmised it will be the case vibrating along.... Nowt you can do other than dampening the vibes down.

[guyb]

I thought that might be the case!

I guess one solution would be to replace the top part of the case with a custom wooden one. I have a friend that is pretty handy in that department.

Would that be a good or bad idea?


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[Ali Tait]

Should be fine.

[Arkless Electronics]

+1

[dowser]

Or place sticky backed dampening material inside the cover, or try small foam pads wherever the top cover touches the chassis. Shouldn't be hard to fix


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[Macca]

Folded bar towel or similar and a weight on top.

Might not pass WAF, though.

[walpurgis]

I had a similar issue with one of my DACs. The mains transformer being noticeably 'buzzy'. I put a small self adhesive pad of Sorbothane between the underside of the top cover and the top of the transformer, leaving the pad under slight compression and making sure air could still circulate around the transformer. This removed about 90% of the noise.

[guyb]

Or place sticky backed dampening material inside the cover, or try small foam pads wherever the top cover touches the chassis. Shouldn't be hard to fix

I was thinking of doing that - I have some of this already - http://www.acoustiproducts.com/en/acoustipack.asp

One issue however - the top slides on to the bottom so I am not sure I would be able to attach it and get the top back on!

Plus, I wasn't 100% sure whether this would be a fire hazard...

[guyb]

I had a similar issue with one of my DACs. The mains transformer being noticeably 'buzzy'. I put a small self adhesive pad of Sorbothane between the underside of the top cover and the top of the transformer, leaving the pad under slight compression and making sure air could still circulate around the transformer. This removed about 90% of the noise.

That would be worth a try :D

[guyb]

I had a similar issue with one of my DACs. The mains transformer being noticeably 'buzzy'. I put a small self adhesive pad of Sorbothane between the underside of the top cover and the top of the transformer, leaving the pad under slight compression and making sure air could still circulate around the transformer. This removed about 90% of the noise.

That did the trick!

A couple of Acoustifeet stuck together and wedged between the top of the transformer and the case!

Not silent but a lot quieter :)

Thanks everyone.

Guy

[walpurgis]

Sorted! :thumbsup: