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In Reply to: RE: Test of Once-Removed Theory posted by May Belt on June 29, 2007 at 04:04:04
Hello May,
I'm afraid I have to admit that this "Once-Removed" theory is a bit more than I can understand. Can you explain or do you have any ideas of why it works and effects the sound? All this time I thought the "magic brick" worked by deading the vibrations of the transformers and the tubes, plus absorbing or effecting the magnetic fields from the transformers.
I'll be making my own DIY "magic brick" but cannot help but wonder if the type of metal used matters? If so what's metal is best, iron, steel, brass, aluminium etc? My plans are to get a bar of whatever metal is best and then veneer a wooden outer layer on it. I don't want the metal to scratch my transformers so I will be adding a layer of felt on the bottom. But if the layers matter will this have a postive or negative effect on the sound? Or maybe I should I forego the wood veneer and just put felt on the bottom of the metal bar?
Thetubeguy1954
Follow Ups:
If you are going to make your own DIY "magic brick" and if you are going to test the two explanations put forward for why the "magic brick" improved the sound, and if one of the explanations was that the chunk of iron inside the "magic brick" absorbed the magnetic field created by the transformer in the equipment, then you have to also use a chunk of iron!!
You say that you don't want the metal to scratch your transformers. Why do you want to put the metal directly onto the transformers ? In the majority of cases, the "magic brick" was placed on top of the equipment's outer CASE !!
You are quite correct in wondering if an additional layer of felt would affect the sound. The answer is yes, as will a second layer of felt as will a third layer of felt !!!
To begin to understand so much, you have to move away from "something affecting the audio signal" or "something affecting the acoustic air pressure waves in the room".
Quite simply, instead of searching for a wooden case in which to place the chunk of iron, use a plain (unprinted) cardboard box !!!
Regards,
May Belt.
MB: If you are going to test the two explanations put forward for why the "magic brick" improved the sound, and if one of the explanations was that the chunk of iron inside the "magic brick" absorbed the magnetic field created by the transformer in the equipment, then you have to also use a chunk of iron!!
TG1954: Of course you're 100% correct "IF" I wanted to make my DIY "magic brick" exactly like VPIs it would have to be iron. My goal is not to simply create an exact DIY copy of VPI's brick. Instead I'm hoping to discover why it worked and then possibly improve it's performance. I'm not very technically adept and I thought there might be other metals known to absorb ot affect magnetic fields even better than iron. If that was the case I'd want to use that metal instead of iron. The idea being that it "might" cause an even greater, better effect. I was hoping you might know which metal is best at absorbing or influencing magnetic fields.
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MB: You say that you don't want the metal to scratch your transformers. Why do you want to put the metal directly onto the transformers ? In the majority of cases, the "magic brick" was placed on top of the equipment's outer CASE !!
TG1954: Unfortunately my transformers are "exposed", yes they're covered by metal cylinder covers but I don't want the covers scratched either. I provided a picture of my amp from the front and side so you can see what I mean. So I'd have to place my DIY brick on top of these covers. Hence the need/desire for felt.
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MB: You are quite correct in wondering if an additional layer of felt would affect the sound. The answer is yes, as will a second layer of felt as will a third layer of felt !!!
TG1954: Ok that's what I'd thought you were going to say.
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MB: To begin to understand so much, you have to move away from "something affecting the audio signal" or "something affecting the acoustic air pressure waves in the room".
TG1954: I'm willing to try and understand that something else besides "affecting the audio signal" or "affecting the acoustic air pressure waves in the room" is happening. Can you begin to help me understand what you're suggesting is actually occuring instead?
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MB: Quite simply, instead of searching for a wooden case in which to place the chunk of iron, use a plain (unprinted) cardboard box !!!
TG1954: Great suggestion. I'll start with that.
Thetubeguy1954
We are making mountains out of molehills!
If you want to improve on the VPI brick, be sure to radius the corners of the laminated steel or iron plates. Of course the thickness of the case matters: magnetic fields weaken with distance also.
Again, seriously examine a transformer. The better ones have more and thinner laminations in order to 'catch' more lines of magnetic force, as each lamination will pass one line of magnetic force. Magnetism would rather travel through ferrous objects than through air. The field traveling through the laminations will induce a current. A copper foil tape will speed this current flow especially if placed occasionally within the iron lams. Grounding the copper will 'sink' that current induced speeding the flow even more.
You may want to check the websites for people like Co-netics, who manufacture mu metal. They have useful tips and advice for magnetic shielding and channeling.
Stu
"The better ones have more and thinner laminations in order to 'catch' more lines of magnetic force, as each lamination will pass one line of magnetic force."
Stu, the transformer has laminations to reduce eddy currents, that's all. Don't forget that lines of magnetic force don't really exist, they're just a mental model to help visualize the magnetic flux density and vector. So, actually a thicker lam will have a lower reluctance and more "lines of force" than a thin one, but it also has lower resistance and thus more eddy current loss.
Regards, Rick
disagree, unfortunately. Why else would manufacturers use multiple laminations in a transformer if one solid piece of metal would be superior? The only time you see solid pieces is in ferrite core material.
Stu
Hi Stu,
I didn't mean to imply that laminations aren't necessary, they are. Without them the eddy current losses kill efficiency and bandwidth. The point I was trying to make was that it's the total effective cross-sectional area, not the number of laminations that determine the flux capacity.
Regards, Rick
Now I understand why you said you would be placing the DIY "magic brick" directly on top of the transformer.
Aside from your desire to make a DIY "magic brick", how many feet does your amplifier sit on ? Four ? I also notice from your photograph that there is a (TV?) stand behind the amplifier - with four feet !!
Now, experiment with the (peculiar) odd and even rule. If your amplifier has four feet, place a plain piece of paper under ONE (only ONE)of the four feet. Listen for a short period of time, then remove the piece of paper. I think when you remove the paper, you will find that you can no longer listen with the same pleasure !!
Carrying on with the experiments place a plain piece of paper under ONE of the four feet of the TV stand, also under ONE of any other four feet of equipment !! Listen for a short time, then remove any one of the pieces of paper ! You will be surprised at the deterioration in the sound !
Nothing to do with vibrations, nothing to do with magnetism, nothing to do with 'something affecting the audio signal', but something to do with how the human being is reacting to their environment !!!!!!!
Regards,
May Belt.
MB: Now I understand why you said you would be placing the DIY "magic brick" directly on top of the transformer.
TG1954: I thought a photo of what the amp looked like would clear that up.
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MB: Aside from your desire to make a DIY "magic brick", how many feet does your amplifier sit on ? Four ? I also notice from your photograph that there is a (TV?) stand behind the amplifier - with four feet !!
TG1954: My amp sits on 3 cones. 2 in the back 1 in the front. These days it sits in a dedicated audio room on a stand between and behind 2 speakers.
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MB: Now, experiment with the (peculiar) odd and even rule. If your amplifier has four feet, place a plain piece of paper under ONE (only ONE)of the four feet. Listen for a short period of time, then remove the piece of paper. I think when you remove the paper, you will find that you can no longer listen with the same pleasure !! Carrying on with the experiments place a plain piece of paper under ONE of the four feet of the TV stand, also under ONE of any other four feet of equipment !! Listen for a short time, then remove any one of the pieces of paper ! You will be surprised at the deterioration in the sound !
TG1954: My CD player (BlueNote Stibbert) picture above has four feet. I'll check out this experiment you mentioned above with this component.
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MB: Nothing to do with vibrations, nothing to do with magnetism, nothing to do with 'something affecting the audio signal', but something to do with how the human being is reacting to their environment !!!!!!!
TG1954: Well May as I've always advocated that one of the reasons why audio equipment measurements and the specs they provide don't correlate with what we hear is due to the human ear/brain and our perceptions being involved, I can believe that some things will affect and influence those perceptions. So I will be starting with the "odd and even rule" you spoke of above.
Thetubeguy1954
By inadvertently using three cones (I will explain the use of the word inadvertently later) you have dealt with the problem of four (even numbers) feet.
Obviously, whoever produced the cones you use must have HEARD the beneficial effect of using three instead of four (or they would have recommended the use of four cones!!!) If you used four cones, the sound would be perceived as 'worse' and you would either have to add a fifth cone or remove the fourth cone.The reason why I use the word inadvertently is because it would not have been a logical step for you to deliberately chose to use only three cones. You either used the number three because it 'sounded' better with three cones or it had been recommended by the producers of the cones that you should only use three (because it would 'sound' better)!!
If the explanation given is that three cones 'deal with' vibrations better - therefore 'dealing with' any adverse effect on the audio signal better, all you have to do is to remove the three cones from under the working amplifier (the sound will now be perceived to have deteriorated) and place the three cones under an identical but PASSIVE amplifier - just sitting passively on a shelf - not connected to the audio system and not connected to the AC power supply - and back will come the 'good' sound !!!!
There is NO audio signal travelling through the PASSIVE amplifier to be adversely affected and yet you will have the 'better' sound back !!
Regards,
May Belt.
By inadvertently using three cones (I will explain the use of the word inadvertently later) you have dealt with the problem of four (even numbers) feet.
Obviously, whoever produced the cones you use must have HEARD the beneficial effect of using three instead of four (or they would have recommended the use of four cones!!!) If you used four cones, the sound would be perceived as 'worse' and you would either have to add a fifth cone or remove the fourth cone.
The reason why I use the word inadvertently is because it would not have been a logical step for you to deliberately chose to use only three cones. You either used the number three because it 'sounded' better with three cones or it had been recommended by the producers of the cones that you should only use three (because it would 'sound' better)!!
If the explanation given is that three cones 'deal with' vibrations better - therefore 'dealing with' any adverse effect on the audio signal better, all you have to do is to remove the three cones from under the working amplifier (the sound will now be perceived to have deteriorated) and place the three cones under an identical but PASSIVE amplifier - just sitting passively on a shelf - not connected to the audio system and not connected to the AC power supply - and back will come the 'good' sound !!!!
There is NO audio signal travelling through the PASSIVE amplifier to be adversely affected and yet you will have the 'better' sound back !!
Regards,
May Belt.
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