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The sound of chassis?

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Joined 2010
Isolation platform,

Two pieces of glass with bubble wrap in between…LOL
Don’t get using blue or black tack or hot glue under caps…the road to ruin.. LOL
:D

Add some Sorbothane Sheet for good measure....perhaps not... :)

Regards
M. Gregg
 
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Disabled Account
Joined 2010
Just for interest,

You can get aluminium sheet with... not sure if its rubber or plastic sandwiched in the middle...no good for heat transfer but I guess another material for chassis bottom that has a damping effect. Quite strong...

I have seen lots of it not sure what its called... :)

Ummm tube dampers..mount the bases on silicon rubber washers..Then again mount the chassis base plate on silicon washers mount the feet to that...it goes on..

Regards
M. Gregg
 
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Disabled Account
Joined 2010
Just for interest,

I wonder what the shielding is like with the aluminium rubber sandwich it has aluminium on both sides. If earthed you have a double skin chassis..Phono stages etc...


I still like wood with some kind of metal foil Mu is probably best..or RFI tape..

Regards
M. Gregg
 
Disabled Account
Joined 2010
Last comment..LOL

Just my thoughts...Chassis levels Power tx vibration eddy currents etc.

If components are on two levels ie top and bottom I like to ensure some mechanical isolation between ie different materials between bolted sections or some form of damping...gaskets come to mind... or something to stop ringing spreading across the structure. Main thing is to maintain good electrical integrity...and earthing. Passing cables through metal work or ferrite beads<<<if you put a supply cable through a hole in metal make sure the return comes through the same hole...if you don't you will heat up the chassis...Eddy currents come to mind.

I guess everyone has there own Ideas.. :)


Regards
M. Gregg
 
I did a lot of work on the LF EQ box for my Infinity speakers and was able to greatly reduce the noise level, as measured using TrueRTA. The noise level nearly doubled, however, when I put the steel lid back on the box; the effect was real and very repeatable, and corresponded to the frequencies emitted by the power supply. I'm thinking that the lid served to increase the noise transfer by induction from the PS half to the EQ half of the box, which are separated with a partition of TI-Shield (see picture). I wonder if making a lid from plastic to replace the steel lid would prevent that effect...
 

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I'll probably end up doing what I should have done in the first place, which is build a separate power supply box using a real center-tapped transformer and diode bridge to supply the +/- 18V required, instead of the wall wart/ voltage doubler setup that came stock.
 
I'd just like to briefly contribute with my little experience.

The preamp i've made was firstly done on a wooden frame with relatively thin copper top plate. Then i changed the top for a thick pine board as the copper and was very touch sensitive (microphonics) and not very stiff because it was thin.

Change in sound was quite apparent and i cannot describe it in terms or good/bad. Surely the first one sounded more metallic with shimmering highs. Not necessarily bad, for example trumpets were amazing, so real. Pipe organs were 'ringing' more. The wooden version removed this bite and made everything more smoothed out and 'theoretically correct' soundwise, more universal, balanced.

Oh and i'm talking about near field listening, no ground shaking stuff.
 
Of interest - research we did at the materials science lab in the 1970s showed that one of the single most effective dampened plate designs was a pair of thin high-tensile aluminum sheets, as the outer sandwich having a filling of clay-impregnated silicone (setting) putty. Clay about 1/3 by weight. We mixed it using a glazers trowel directly on the bottom plate, then spread it (by trowel) out to about 1 mm thick, as uniformly as possible. To apply the top plate, it was alcohol and methyl-ethyl-ketone cleaned first (as was the bottom plate, MEK from ACE hardware), and very slightly bent into a curved form. Doing so allowed one edge to be clamped down, then the other (curved up a few centimeters) pressed down and again clamped. To cause the silicone to cure, just before clamping, we sprayed it with a woman's perfume atomizer, with ordinary water. Very little. 1/50th the amount of the silicone.

The plates of course overnight were bonded. They became as "dead as lead", yet had the strength and resilience of the aluminum.

Mercedes Benz, Boeing, McDonald-Douglas, Toyota and quite a few Japanese elevator manufacturers consider it now to be their "proprietary/patented" technology. This doesn't prevent it from being used for OTHER purposes though, especially microphonics reduction.

GoatGuy
 
indeed. there is no universal system that can do everything the best. people often talk about 'fidelity', original information on the medium etc.. and it all becomes irrelevant once we want to transform it to mechanical waves.

long ago i experimented with cheap stick-on transducers. in general the complex sound was rubbish of course, but when i put it on acoustic guitar and played Paco de Lucia or even solo violin tracks, it was unbeatable since my guitar physically played it. im still planning to make some dedicated speakers for wooden acoustic instruments as well as for brass, just for special occasions. to some extent its the same for chassis as i see it. but of course, there are many things that 'matter' more for sure.
 
Well, this is not what I meant.

Talking about the "sound" of certain chassis materials sounds more than eccentric, even esoteric to me, as I bet that no physical or chemical parameters related to chassis materials are reliably (!) proven to have any influence on the "sound" of an amplifier at all. A chassis' only duties are to provide mechanical stability and electro-magnetic screening.

Best regards!
 
Well, this is not what I meant.

Talking about the "sound" of certain chassis materials sounds more than eccentric, even esoteric to me, as I bet that no physical or chemical parameters related to chassis materials are reliably (!) proven to have any influence on the "sound" of an amplifier at all. A chassis' only duties are to provide mechanical stability and electro-magnetic screening.

Best regards!
hi Kay,
i was thinking like this for years and i still accent importance of another factors contributing to sound, but we cannot overlook the phenomenon of microphonics, especially with tubes and capacitors. I realized it on my chassis rebuild described above and i wasn't expecting anything sound-wise (i just wanted more rigid chassis) so no mind programming took place. I'm not over-emphasizing it though..
 
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