View Full Version : Advice on vibration damping material for a power amp cover
Hi all I'm looking for something to deaden the vibrations on an amplifier cover, the toroid hums a bit when there is no case on but I can live with that.
The problem is when I replace the cover the vibration/hum is amplified to a level where it is noticeable in any lulls in the music, and I can't leave it off for fear of cooking one of the many furry critters running about.
So I am looking for something thin (no more than about 5mm )and self-adhesive but hopefully not bitumin based as it's a class A power amp and does get a tad warm and I don't want something melting into the innards. I was thinking of using the car deadening stuff but all I can find has a bitumin layer.
Any advice/recommendations?
You could try a few strips of this stuck to the underside:
https://www.ebay.co.uk/itm/291500425176
brian2957
23-02-2017, 10:15
Something like this is usually very effective Martin http://www.ebay.co.uk/itm/RATTLEMATT-x-8-SHEETS-Car-Audio-Sound-Deadening-Proofing-Sheets-Pads-Panels-/290790146520?hash=item43b47181d8:g:jMcAAOxy1klRdWl 9
Yeah don't use that Dynamat, I had that on the inside of my amp cover that the previous owner had fitted and it took 3 hours and many chemicals to remove!
I'm sure someone will be along with an alternative.
Open Door
23-02-2017, 10:35
http://www.partsconnexion.com/damping_soundcoat.html
I didn't think I'd be alone in having this problem:) thanks for the advice chaps.
@Shane never would have thought of a golf product, nice one, bout time that "sport" was good for something.
@Brian looks like the stuff in my CDP that I can't for the life of me remove but at least the bitumin is covered on your recommendation, the stuff in my CDP above the valves:rolleyes::mental: is just bare bitumin so I leave the cover off for obvious reasons.
@Mike sounds like the same stuff as in my CDP, evil, impossible to remove stuff that definately should not be fitted over tubes:doh:
http://www.partsconnexion.com/damping_soundcoat.html
Thanks Robert.
This looks like the winner, thanks for all the time and effort chaps, much appreciated:)
http://www.partsconnexion.com/damping_soundcoat.html
I was thinking of that stuff as I saw you had it in an item you were selling but I didn't know what it was, no doubt similar to what they use under car bonnets 👍
I suppose the other alternative is a thicker cover?
Yeah, Colin Wonfor had my amp in for a minor repair and removed the Dynamat with some nasty chemical and it took him 3 hours and much gnashing of teeth and sweat no doubt. I'm just glad it wasn't me who fitted it, but I know who did 😉 😀
Its fine in speakers etc but not in anything that gets warm.
Yeah, Colin Wonfor had my amp in for a minor repair and removed the Dynamat with some nasty chemical and it took him 3 hours and much gnashing of teeth and sweat no doubt. I'm just glad it wasn't me who fitted it, but I know who did �� ��
Name and shame game? Probably best not, presume they're a member here.:D
Had a quick go at the stuff on my CDP, no chance of removing that quickly. Nasty stuff once heated.
Sherwood
23-02-2017, 11:02
If its damping you want, why not make up a couple of bean bags with silica gel crystals. Quite massy and heat resistant. You dry out the crystals in the oven or microwave.
Geoff
brian2957
23-02-2017, 11:11
Have you tried sitting something heavy on top of the unit to see if that helps Martin ?
The other way would be to try dampening the casing underneath .
If its damping you want, why not make up a couple of bean bags with silica gel crystals. Quite massy and heat resistant. You dry out the crystals in the oven or microwave.
Geoff
Another excellent idea, thank you but I'm gonna try the sound coat stuff Robert recommended, if thats not enough I will try yours as well.
Have you tried sitting something heavy on top of the unit to see if that helps Martin ?
The other way would be to try dampening the casing underneath .
It'll have to be inside the casing as I've got very little room above it as it's in a unit rather than an adjustable rack and it's a bit of a beastie size wise.
Have you tried sitting something heavy on top of the unit to see if that helps Martin ?
The other way would be to try dampening the casing underneath .
Yeah bags od silica sand on top. You get them for speakers, but can make em up yourself. You can buy the leather gem type bags and fill them with play sand or ball bearings. Can look really cool.
walpurgis
23-02-2017, 11:39
I had a DAC with a mains transformer that was causing a buzz through the top panel. I inserted a small pad of Sorbothane between the top of the transformer and underside of the top panel to quieten things. It worked!
A small slate placemat on top.
It will add mass and probably be thin enough to fit. Easy to remove and will leave no residue.
I had a DAC with a mains transformer that was causing a buzz through the top panel. I inserted a small pad of Sorbothane between the top of the transformer and underside of the top panel to quieten things. It worked!
Another good idea, nice one Geoff, I've got some of them semi-circular equipment feet knocking about somewhere that should do
A small slate placemat on top.
It will add mass and probably be thin enough to fit. Easy to remove and will leave no residue.
Funny you should mention slate Kevin, I've just stuck a chopping board on top with some diy carpet underlay feet on top and it's helped quite a bit, great minds........eh;)
Should be able to get the toroid to shut up with my DC blocker and all the helpful hints off here. It's already 20% quieter and I haven't had the top off to play about yet.
Glad I asked, cheers all:)
Lovely helpful forum.:respect:
RothwellAudio
23-02-2017, 14:31
A picture of the amp would be a big help. For example, where are the vent holes (if any)?
Anyway, it's possible that the movement of the metal top plate isn't in itself a problem - it could be that the top plate is "chattering" where it comes into contact with the sides. Sometimes just adjusting the tightness of screws can tune it out.
If it was mine I would look at all other alternatives before applying sticky stuff.
A picture of the amp would be a big help. For example, where are the vent holes (if any)?
Anyway, it's possible that the movement of the metal top plate isn't in itself a problem - it could be that the top plate is "chattering" where it comes into contact with the sides. Sometimes just adjusting the tightness of screws can tune it out.
If it was mine I would look at all other alternatives before applying sticky stuff.
It's an Advance Acoustic MAA-406, I'm afraid I still can't manage to post pictures but here's a link to google images https://www.google.co.uk/search?q=Advance+Acoustics+MAA+406&client=firefox-b&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj67PS1uKbSAhUoKsAKHXdeDDIQ_AUICSgC&biw=1366&bih=696 if that helps, I also didn't get the discs for the bottom of the feet which have a sorbothane pad which I suppose doesn't help, so thats another avenue I have to explore.
i have tried different tension on the screws and it doesn't seem to make an audible difference, it just seems that the top cover amplifies the hum, if I hold it I can feel a very slight vibration through the cover, it is a cheap thin piece of steel, once removed it doesn't even hold its shape properly.
RothwellAudio
23-02-2017, 15:09
Are these two different models?
http://www.audiocostruzioni.com/r_s/ampli/amplificatori/advance-acoustic-maa406/advance%20acoustic%20maa%20406%20ampli%202013.jpg
http://audiophillness.com/wp-content/gallery/maa-406/MAA-406-12_zps4kklkhrn.jpg
Anyway, I would try to put something compliant in between the top panel and whatever it comes into contact with. You can buy sheets of felt from Hobbycraft for about 50p which might stop one panel chattering against the other.
An alternative approach would be to consider this: is the vibration caused by the mains transformer vibrating, or is the magnetic field from the mains transformer inducing eddy currents directly into the top plate? If it is the former, it might be possible to isolate the mains transformer from the metalwork by sitting it on rubber. They usually have a rubber washer anyway, but examining it closely to see if it can be isolated better by prove fruitful.
http://www.audiocostruzioni.com/r_s/ampli/amplificatori/advance-acoustic-maa406/advance%20acousti%20maa%20406.jpg
Well blow me it worked, this is how mine looks but this is a stock photo
walpurgis
23-02-2017, 15:25
Nice looking piece of kit! :D
Thanks for that Robert, the transformer is sitting on a round disc of rubber with another on top before the steel washer, so thats already done but it does sit on a steel tripod, I presume to keep the large bottom nut from coming into contact with the baseplate so maybe this could also be a good place to introduce something like your felt idea?
Can't really fit anything like sheet material on top of the toroid without obscuring the top vent, so maybe I'll try Geoffs Sorbothane idea and use an equipment foot if I can find them.
Are these two different models?
http://www.audiocostruzioni.com/r_s/ampli/amplificatori/advance-acoustic-maa406/advance%20acoustic%20maa%20406%20ampli%202013.jpg
http://audiophillness.com/wp-content/gallery/maa-406/MAA-406-12_zps4kklkhrn.jpg
Anyway, I would try to put something compliant in between the top panel and whatever it comes into contact with. You can buy sheets of felt from Hobbycraft for about 50p which might stop one panel chattering against the other.
An alternative approach would be to consider this: is the vibration caused by the mains transformer vibrating, or is the magnetic field from the mains transformer inducing eddy currents directly into the top plate? If it is the former, it might be possible to isolate the mains transformer from the metalwork by sitting it on rubber. They usually have a rubber washer anyway, but examining it closely to see if it can be isolated better by prove fruitful.
Nice looking piece of kit! :D
Looks mint on a night:stalks: lovely sounding piece of kit as well, very dynamic.
http://www.mokandmartensen.com/v/vspfiles/photos/ADVMAA406-2.jpg
Any ideas what I can use to replace the missing discs for the feet?
This is what mine looks likehttp://www.soundhifi.com/advance/images/MAA406_back.jpg
Feet that you use under spikes would seem to be perfect. Are they called spike cups?
Feet that you use under spikes would seem to be perfect. Are they called spike cups?
Excellent idea, they would look the part as well, nice one Kevin
RothwellAudio
23-02-2017, 15:41
...I presume to keep the large bottom nut from coming into contact with the baseplate so maybe this could also be a good place to introduce something like your felt idea?
Can't really fit anything like sheet material on top of the toroid without obscuring the top vent...
No, I wouldn't put felt near the transformer. Heavy duty rubber to act as a cushion between the transformer and case is what I had in mind.
Use the felt between the top plate and whatever the top plate rests on.
Feet that you use under spikes would seem to be perfect. Are they called spike cups?
Not exactly what I had in mind:Dhttp://thumbs.ebaystatic.com/images/g/2mAAAOSwOVpXVRoD/s-l225.jpg but thats what ebay came up with, very helpful....not
No, I wouldn't put felt near the transformer. Heavy duty rubber to act as a cushion between the transformer and case is what I had in mind.
Use the felt between the top plate and whatever the top plate rests on.
I have some 40mm circular sorbothane feet somewhere which I presume would be suitable and can be cut to give the proper thickness for between the case and transformer, I'll have a dig about this evening,
Not exactly what I had in mind:Dhttp://thumbs.ebaystatic.com/images/g/2mAAAOSwOVpXVRoD/s-l225.jpg but thats what ebay came up with
These look more like ithttp://thumbs.ebaystatic.com/images/g/7cUAAOSwr~lYoF-R/s-l225.jpg and duly ordered
Thanks for holding my hands everyone:), I should be okay now, I'll post the results when I get the necessary materials
All materials have arrived:-
Case has been felt lined on all contact points, no more vibration detectable, good shout Andrew.
Spike cups with sorbothane pads fitted, another slight improvement and it looks much better, nice one Kevin.
Still a little bit of Toroid noise from my seating position so I had to resort to lining the steel box the transformer sits in with some of that car deadening sheet that Brian recommended, now it's only audible when I'm virtually on top of it.............result:)
Didn't need the stick on golf stuff but thanks for the idea Shane, sure I'll find a use for it somewhere.
Again many thanks to all who contributed.
hard1175
10-03-2017, 09:51
Hi Martin
have a look at foQ damping sheet a friend of mine has used it with some very positive results.
Contact
Concertoaudio.co.uk
Bernie
Hi Martin
have a look at foQ damping sheet a friend of mine has used it with some very positive results.
Contact
Concertoaudio.co.uk
Bernie
Thanks Bernie I'll check that out
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