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vortecjr

Introducing Dark Matter system clarifier by Barrows Worm

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48 minutes ago, vortecjr said:

It’s always fun to sit back and watch people in a forum get worked up over nothing. RF absorbing material is nothing new, readily available, and well documented.

I'm only trying to understand the benefit of a small piece of RF absorbing material that doesn't begin to cover even one side of the equipment. Sure, it will shield against RF sources in the narrow cone defined by the component and the black box. That just doesn't seem particularly useful.

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46 minutes ago, mansr said:

I'm only trying to understand the benefit of a small piece of RF absorbing material that doesn't begin to cover even one side of the equipment. Sure, it will shield against RF sources in the narrow cone defined by the component and the black box. That just doesn't seem particularly useful.

mansr:  Dark Matter is not shield.  It works by coupling with RF energy and converting it to heat.  One places it where one expects there to be a source of RF, and at that location it damps the RF energy.  Shields are different, they do not damp the energy, they just reflect it.

So far in my testing I placed one inside my amplifier, with the AC input wiring running directly over it.  This proved to be effective in improving sound quality in listening tests.  I recommended the same approach to other testers, and I just asked the testers to report their findings, without giving them any expectations (I did not relate my experience to them, jus asked to see if they hear any differences), and the testers reported similar results to mine.  At this point I decided that it might be worthwhile to make it available.

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6 minutes ago, barrows said:

mansr:  Dark Matter is not shield.  It works by coupling with RF energy and converting it to heat.  One places it where one expects there to be a source of RF, and at that location it damps the RF energy.

Whatever the mechanism, it can only interact with radiation that actually hits it.

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34 minutes ago, mansr said:

Whatever the mechanism, it can only interact with radiation that actually hits it.

Yes, that is why placement is important.  The point is that it reduces the level of the RF which it encounters, so when placed in a location where there is a lot of RF, the net result is less RF to propagate into sensitive circuitry.

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2 minutes ago, barrows said:

Yes, that is why placement is important.  The point is that it reduces the level of the RF which it encounters, so when placed in a location where there is a lot of RF, the net result is less RF to propagate into sensitive circuitry.

Yes, but it must be placed such that the sensitive circuit is within the shadow cast by the absorber. Seems to me a flat sheet would be rather more efficient than a cube in achieving this.

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1 hour ago, mansr said:

I'm only trying to understand the benefit of a small piece of RF absorbing material that doesn't begin to cover even one side of the equipment. Sure, it will shield against RF sources in the narrow cone defined by the component and the black box. That just doesn't seem particularly useful.

We are trying to understand it as well and that is the point of the exercise. If there is anything that has the potential to compliment projects we are working on it might be worth investigating it.

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21 minutes ago, mansr said:

Yes, but it must be placed such that the sensitive circuit is within the shadow cast by the absorber. Seems to me a flat sheet would be rather more efficient than a cube in achieving this.

 

I had mentioned this earlier in the thread.  Here was @barrows' reply:

 

On 7/21/2018 at 9:31 AM, barrows said:

There are many approaches which could be used to apply these substances to cables.  The molded blocks could be drilled through, and then cables threaded through the holes.  It is likely possible that flexible sheets could be made as well.  Dark Matter in its current form is encapsulated in a flexible epoxy matrix.  But for it to be made in  flexible sheet would likely require less of the active compounds.  One thing in the making of these is that I really wanted to use much higher quantity of the active compounds than are used by similar products and achieving that requires some cubic area.

 

If one was manufacturing cables, there are various methods to incorporate Dark Matter.  In fact I am aware of at least one cable manufacturer that applies similar materials to their power cables in the form of a can, or block, around a portion of the cable length which contains the compound(s).  But I am not here to (specifically) discuss other company's products which may be similar.  

 

Edit: So I suppose if you wanted to take the sheet approach, you'd build a little block wall of these things.  They could have made quite thick sheets to avoid the need for this, but then they'd presumably be more expensive.  Thus if some RF infiltration of sensitive circuitry is unavoidable in your system without substantial cost, you'd want to see if you could purchase the minimum number of cubes to put that circuitry in shadow at lower cost.

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2 minutes ago, Jud said:

I had mentioned this earlier in the thread.  Here was @barrows' reply:

 

On 7/21/2018 at 4:31 PM, barrows said:

One thing in the making of these is that I really wanted to use much higher quantity of the active compounds than are used by similar products and achieving that requires some cubic area.

A cubic mile of the stuff won't do you any good if it isn't between the radiation source and the item in need of protection.

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2 minutes ago, mansr said:

A cubic mile of the stuff won't do you any good if it isn't between the radiation source and the item in need of protection.

 

Right, thus my edit (don't know if you'd seen that when you replied):

 

7 minutes ago, Jud said:

Edit: So I suppose if you wanted to take the sheet approach, you'd build a little block wall of these things.  They could have made quite thick sheets to avoid the need for this, but then they'd presumably be more expensive.  Thus if some RF infiltration of sensitive circuitry is unavoidable in your system without substantial cost, you'd want to see if you could purchase the minimum number of cubes to put that circuitry in shadow at lower cost.

 

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9 minutes ago, Jud said:

Edit: So I suppose if you wanted to take the sheet approach, you'd build a little block wall of these things.  They could have made quite thick sheets to avoid the need for this, but then they'd presumably be more expensive.  Thus if some RF infiltration of sensitive circuitry is unavoidable in your system without substantial cost, you'd want to see if you could purchase the minimum number of cubes to put that circuitry in shadow at lower cost.

A better approach would probably be to use as many layers of a thinner sheet as are needed. No gaps between cubes that way, and sheets could be made (somewhat) flexible.

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10 minutes ago, mansr said:

A better approach would probably be to use as many layers of a thinner sheet as are needed. No gaps between cubes that way, and sheets could be made (somewhat) flexible.

 

I can definitely see a role for you on the design team.  😉 

 

A potential disadvantage to the sheet approach:  If you have something that acts like a point source and is to one side of the rest of the circuitry, a block or two may do.  With sheets, you might always wind up using multiple applications.

 

Edit: Hey, what about blocks *and* sheets?  😄

 

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11 minutes ago, Jud said:

A potential disadvantage to the sheet approach:  If you have something that acts like a point source and is to one side of the rest of the circuitry, a block or two may do.  With sheets, you might always wind up using multiple applications.

The absorber will be more effective placed near the target. Even if you have a point source, with a cube placed near it, diffraction will allow some radiation to reach a distant target. Moreover, the source of interference might be something like a nearby cell tower that you can't address at the origin.

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16 minutes ago, pkane2001 said:

 

Spray bottle, like insulation foam?

 

 

you can buy bucket of RAM online - you'd need to see if it is sprayable or use brush & roller

 

BTW, more likely emitters are acting as line sources, not point sources - so don't forget the geometry can effect deviations form the inverse square law

 

 

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1 hour ago, mansr said:

Yes, but it must be placed such that the sensitive circuit is within the shadow cast by the absorber. Seems to me a flat sheet would be rather more efficient than a cube in achieving this.

It appears to me that you are still thinking of Dark Matter as if it were a shield?  Dark Matter reduces RF energy-the idea is that one places it at sources of high RF, and it reduces that energy.  The result being that there is now less RF energy present which will propagate into sensitive circuits.

Think of my example of placing it where AC wiring enters a chassis (or better yet, internally where the AC wires enter the chassis).  Now I have seen spectral analysis of AC lines in a few locations (back when I worked for PS Audio, and we had a spectrum analyzer) and there often is quite a bit of high frequency trash on the AC line.  By placing Dark Matter at the AC input of the component, that RF is reduced where it is in a high concentration before it has a chance to propagate into sensitive circuits.

I am not suggesting it eliminates all RF energy or anything, nor that it "attracts" RF energy, it acts on RF which is passing through it, and reduces it.  It is just another device in the effort to reduce the effects of noise on system performance.

 

The form factor is as it is for both ease in making it, and for flexibility in where and how it can be used.  It would be very fragile if made into flat sheets, likely too fragile to be reasonable.  

If one is looking for something in a flat sheet form, there are a number of industrial products which work quite well for this already available, the only drawback is that they are composed of ferrites, and I do not like ferrites around analog circuitry.  The sheets are a bit more expensive as well.

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6 minutes ago, barrows said:

It appears to me that you are still thinking of Dark Matter as if it were a shield?  Dark Matter reduces RF energy-the idea is that one places it at sources of high RF, and it reduces that energy.  The result being that there is now less RF energy present which will propagate into sensitive circuits.

Call it what you will, it can only interact with radiation that hits it. Whatever passes beside it is unaffected.

 

6 minutes ago, barrows said:

Think of my example of placing it where AC wiring enters a chassis (or better yet, internally where the AC wires enter the chassis).  Now I have seen spectral analysis of AC lines in a few locations (back when I worked for PS Audio, and we had a spectrum analyzer) and there often is quite a bit of high frequency trash on the AC line.  By placing Dark Matter at the AC input of the component, that RF is reduced where it is in a high concentration before it has a chance to propagate into sensitive circuits.

Now you're talking about frequencies carried along a wire rather than as EM waves. To stop those, you typically use a choke. A cube placed beside a wire does not an efficient choke make.

 

6 minutes ago, barrows said:

I am not suggesting it eliminates all RF energy or anything, nor that it "attracts" RF energy, it acts on RF which is passing through it, and reduces it.  It is just another device in the effort to reduce the effects of noise on system performance.

Just what are you suggesting that it does? It's not a shield, and it's not a choke, and it's not a tiny black hole in a box, so what is it?

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On 7/21/2018 at 3:47 PM, plissken said:

 

I may have missed where the return policy is for these devices. 

There is not one.  Not sure where anyone got this idea?  A return policy on something this affordable would not be sensible business.  I prefer to offer this at an affordable price, rather than using the approach of pricing it so high that it is acceptable business to take the time and effort required to deal with a 10%-15% return rate.

This is personal business decision, and I will not make any judgement on those companies which  do otherwise.

 

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I think you said there was a return policy early in the thread.

 

mansr - it would be most effective if it was in between source and receptor, but some ray tracing and using the view factors will convince you it might reduce RF even if not in the direct beam

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@mansr.  I am not sure how many more times or how many more ways I can describe this.  I know you to be a smart and reasonable guy, so i am a bit confused as to your lack of getting it?

 

Right, not a choke

 

Right, not a shield

 

It couples with RF energy and converts some of that energy to heat, by conservation of energy, there is then less RF present.

 

This is similar to @wgscott's water analogy, essentially, but much more practical than putting a salt water aquarium inside  a component!

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3 minutes ago, Ralf11 said:

mansr - it would be most effective if it was in between source and receptor, but some ray tracing and using the view factors will convince you it might reduce RF even if not in the direct beam

Sure, it might reduce emissions that would otherwise be reflected by something onto the target. It won't affect line of sight paths not passing through the device.

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3 minutes ago, barrows said:

It couples with RF energy and converts some of that energy to heat, by conservation of energy, there is then less RF present.

Fine, but in order to "couple," it must be exposed to the RF energy (radiation) in the first place.

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