Pour ma part il me semble avoir prouvé que ce ne sont pas les vibrations qui polluent mais bien les cem confinés par l'alu car il suffit de poser une feuille d'alu alimentaire sur la platine recouverte du capot ctp pour retomber dans les travers du capot d'origine...
A ce propos il serait très judicieux de déplacer le transfo a l'extérieur du lecteur pour éviter la pollution cem et les vibrations (vissé sur la carte electronique!!!) puis de compartimenter l'appareil avec de l'alu de part et d'autre de la mécanique tout en ayant un capot transparent à la cem. On pourrait même orienter les cloisons compartimentrices vers le haut pour "refleter" la pollution interne vers les nuages et éviter qu'elle ne joue au ping pong avec les flancs...
Sinon le top du top serait d'absorber mais la plaque de ce matériau coute aux environ de 300 euros pour du 40x40 cm
Au fait chez brinkmann on fait de même sur les amplis...
http://www.brinkmann-audio.de/main.php? ... ed&lang=en
ET voici un extrait du concepteur des produits nva:
Q: Why don't you use screws?
A: It all started because when I first put the circuit together, I was listening to the amplifier in early bread boarded state, and I was very happy with the circuit. I designed a case, I put it in the case, and it was not as good. I could never understand this, so I started to investigate. The first thing I came up with was that it was steel that was the major problem. You see, a case of steel has a very strong effect on the sound. My theory on this is that there is a lot of magnetic field, that is not only coming off the transformer, but it comes off all AC circuits, comes off the capacitors, comes off the transistors. Now, with a steel case, it cannot get out of the amplifier, just bounces around inside, that turns the sound muddy and loses information. Our next case was made of aluminum, a good change, but I still was not entirely happy. I still could not understand why the original sounded better. Then I had an idea, to actually form the case, almost like a carved shell in one whole lump, that was better again. Then we made a case with no electrical connections between the panels, that worked better. I started to think: `Why is it better?', and the only thing I could think of was the screws. So the next stage was to think: `If it is the screws, then it could also be the electrical connections between the panels, because when you break the whole amplifier, you have no case'. So we designed a glued case, where the actual panels have no electrical connections between them at all, the case itself is anodized, the glues are electrical insulators - so it created a case, that electrically wasn't a case. There is a disadvantage to it, as you cannot put an amplifier of this type near to a phono stage - you know, the field is getting out very easily, creating induced noise, but it made such a sonic difference. The next stage was to look inside the amplifier, I said, OK, how can we remove more screws. We then came to the conclusion that we could actually glue the capacitors down, we could glue the circuit board down, we even found a thermally conductive glue, to glue the output devices down, so we don't need any screws there. And then the amplifier sounded better again. It gives you more of the information of the music, gives you more insight into the music, lets you see how the musicians want to play with each other. My theory is that the whole planet creates electro-magnetical field, which is the poles. Whenever you use a screwdriver to do up a screw, that screwdriver becomes magnetic. If you use it as much to undo, as to do up, it demagnatizes. So I told myself, something is going on here. I also have a theory about twisted cables. They create a magnetic field, and I don't like that. Our NVA cable, when we tried to twist it, the sound became worse. And as soon as you twist the cable, the cable becomes directional. If you don't twist the cable, it is no longer directional. We couldn't glue the transformer because it was too heavy, so we had to bolt it. Basically, it was the process of trying to create a case that has no sonic signature.
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Q: But isn't it easy to get interference when the case cannot block it out?
A: This I agree. You see everything is compromises. If you allow everything to get out, then everything can get in. We suffer from it, but we suffer from it mostly in analogue. The thing that gets most affected by it is the phono stage. Whenever we got the the Heathrow show in London, we always had a room, which was overlooking the forcourt of the hotel. Whenever a taxi came, you could hear him talk to base. We have a dealer who has a taxi office right next to his shop. He cannot use my amplifiers with a disc stage on them, because they've got an AM transmitter. Whenever they switch on the AM transmitter, there will be a big `bang' coming out of the speaker. So it is a great disadvantage, but this is a good compromise to my mind, because it make the music better. There are very few people who live next to transmitters, or who live next to taxi offices. If I've got customers that have that kind of problem, I'll help them out.
Source:
http://nva.sclnz.com/