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Old 3rd January 2006, 04:02 PM   #1
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Default Vibration Control for UcD 700

I've been thinking about vibration control for the UcD 700 and have decided I will experiment with potting the amplifier and power supply modules by suspending them in Fluorinert. The Fluorinert will act as a cooling agent, and will damp incoming and module-generated vibrations. The main question I have regarding this experiment is what material should I use for the potting can .... aluminum, copper, acrylic? I think acrylic is inadvisable for the amplifier module because of heating concerns. As for copper or aluminum cans, I can see both a cost and benefit of shielding: incoming EMI would be bounced away while outgoing EMI would be bounced back and returned to source, as it were. Has anyone any thoughts about what material might be optimal?
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Old 3rd January 2006, 05:21 PM   #2
SSassen is offline SSassen  Netherlands
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Oh c'mon, get real, if you're that afraid of microphonics you should then also suspend your speaker cables above the floor and route your interlinks through 4" sand filled tubes. Really, you're looking for solutions where there's no problem.

Furthermore you failed to spot one obvious flaw in your reasoning, and that's the simple fact that a liquid is not compressible and hence conducts vibrations several magnitudes better than air, so if you're serious about cancelling microphonics you should be operating the amplifier in a vacuum, where no air induced vibration can get to it.

Whether your electrolytic caps will like being operated in a vacuum I wonder, they might decide to blow up on you due to the pressure difference

Best regards,

Sander Sassen
http://www.hardwareanalysis.com
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Old 3rd January 2006, 06:07 PM   #3
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Furthermore it will only act as a cooling agent if you cool it, unless a set limitation of use is appealing to you.

Consider also the time constant of the cooling system you haven't considered to employ, and also the time it would take for the temperature to establish some level of steady state, and all the effects associated with that.

Had you considered also the physical properties of the enclosure and it's affects on the turbulence of the transmitted vibrations through the liquid?

So you're probably thinking I'll just add heatsinks ... had you considered hotspots? The fluid would have to flow.

What are the electrical properties of the fluid, I know it's the thing to use, but this stuff wasn't designed for audio. Dielectric properties etc.. I hope this is starting to look silly to you too.

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Old 3rd January 2006, 07:43 PM   #4
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....incidentally, I know they say that fluid is good for damping vibrations. I would think that's more from the point of view of the noise emitted from an old hard drive placed within it, being better distributed amongst the surface of the enclosure, changed frequencies etc.

From the point of view of pressure waves hitting the enclosure from the outside, being transmitted to the electronics within, consider a water hammer.

If you can demonstrate this being an audible or even a measurable problem under normal working conditions, I'll make it my life's goal to solve it for you.

Regards,
Chris
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Old 3rd January 2006, 08:41 PM   #5
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Hi, Sander, I think I'm more fearful of microphonics than afraid of them, but that's to put quite a fine point on it.

I use vibration control for my home setup, and find it among the nice additions to better sound.

I don't think hotspots would be a problem as Fluorinert has decent thermal conductivity .... if used in a metal container, it should cool the UcD module sufficiently. I don't plan to run the module ever near 700W.

As to damping vibrations, I do like the quiet of submerging my head in the tub. That's as far as my experimenting with liquid vibration control taken me so far. Problem is when I submerge my head in the tub I can't hear my UcDs, so then I thought, why not submerge the UcDs instead?
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Old 4th January 2006, 12:10 AM   #6
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That's funny. I do hope you're still laughing as hard when your modules go up in bubbles.

This fluid is actually a coolant, but as with most liquid cooling systems you need both a suitable heat exchanger, which isn't a simple enclosure, and a means to circulate the coolant.

I wouldnt' dismiss this advice if you're going to try this.

Then there's still the water hammer argument.

When you submerse your head in the tub, hit the side of of it with something hard and tell me if you think it's dampened when you hear it under the water.

It's evident you've put little thought into this. I think you're doing it for the cool factor, but going about it in this way just isn't.

As far as vibration control improving things, sure, on a CD transport, or rattling windows.

Regards,
Chris
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Old 4th January 2006, 02:00 AM   #7
cowanrg is offline cowanrg  United States
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not to mention that coolant is FAR too expensive for your needs. mineral oil would serve the purpose just fine.

micro-harmonics travel through liquids better than air. tap on your tub with your head under water. think sonar?

if you really want to deal with microharmonics, deal with mounting the module suspended somehow, or isolate it the way a turntable platter would be mounted, etc. you just dont need to submerge it in a fluid.
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Old 4th January 2006, 03:43 AM   #8
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Chris, nothing I do in audio is for the cool factor. I have some Fluorinert left over from a capacitor project I have going now (Fluorinert capacitors, now that's cool ... 1.75 dielectric constant, baby). I got wondering if perhaps the output inductors on the UcD boards could use some damping in the way wiring of electrical transformers is damped by potting. As to incoming vibrations it seems I'm no further ahead using liquid.
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Old 4th January 2006, 05:49 AM   #9
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If your coil hums.... teach it the lyrics.
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Old 4th January 2006, 05:56 AM   #10
cowanrg is offline cowanrg  United States
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it was bruno or jan-peter that told me that the coils make noise because they expand and contract to the frequency of the signal. this makes sense of course. im sure damping this somehow would be a very bad idea. my explaination is no more scientific than your bathtub analogy, but its logical.

if something is creating a mechanical contractions and not causing harm to itself, but merely producing heat (energy), i would think that doing something to defeat those vibrations or contractions would have a negative effect. the energy is being created, and translating into mechanical movement of the coil. if you stop that from happening, it will just heat up MORE and could possibly cause overheating. or, maybe the coil wont operate as intended, etc...
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